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1

Identification of mycobacterial alpha-glucan as a novel ligand for DC-SIGN: involvement of mycobacterial capsular polysaccharides in host immune modulation.  

PubMed

Mycobacterium tuberculosis possesses a variety of immunomodulatory factors that influence the host immune response. When the bacillus encounters its target cell, the outermost components of its cell envelope are the first to interact. Mycobacteria, including M. tuberculosis, are surrounded by a loosely attached capsule that is mainly composed of proteins and polysaccharides. Although the chemical composition of the capsule is relatively well studied, its biological function is only poorly understood. The aim of this study was to further assess the functional role of the mycobacterial capsule by identifying host receptors that recognize its constituents. We focused on alpha-glucan, which is the dominant capsular polysaccharide. Here we demonstrate that M. tuberculosis alpha-glucan is a novel ligand for the C-type lectin DC-SIGN (dendritic cell-specific ICAM-3-grabbing nonintegrin). By using related glycogen structures, we show that recognition of alpha-glucans by DC-SIGN is a general feature and that the interaction is mediated by internal glucosyl residues. As for mannose-capped lipoarabinomannan, an abundant mycobacterial cell wall-associated glycolipid, binding of alpha-glucan to DC-SIGN stimulated the production of immunosuppressive IL-10 by LPS-activated monocyte-derived dendritic cells. By using specific inhibitors, we show that this IL-10 induction was DC-SIGN-dependent and also required acetylation of NF-kappaB. Finally, we demonstrate that purified M. tuberculosis alpha-glucan, in contrast to what has been reported for fungal alpha-glucan, was unable to activate TLR2. PMID:19783687

Geurtsen, Jeroen; Chedammi, Sunita; Mesters, Joram; Cot, Marlčne; Driessen, Nicole N; Sambou, Tounkang; Kakutani, Ryo; Ummels, Roy; Maaskant, Janneke; Takata, Hiroki; Baba, Otto; Terashima, Tatsuo; Bovin, Nicolai; Vandenbroucke-Grauls, Christina M J E; Nigou, Jérôme; Puzo, Germain; Lemassu, Anne; Daffé, Mamadou; Appelmelk, Ben J

2009-10-15

2

Tailoring enzymes acting on carrier protein-tethered substrates in natural product biosynthesis.  

PubMed

Carrier proteins (CPs) are integral components of fatty acid synthases, polyketide synthases, and nonribosomal peptide synthetases and play critical roles in the biosynthesis of fatty acids, polyketides, and nonribosomal peptides. An emerging role CPs play in natural product biosynthesis involves tailoring enzymes that act on CP-tethered substrates. These enzymes provide a new opportunity to engineer natural product diversity by exploiting CPs to increase substrate promiscuity for the tailoring steps. This chapter describes protocols for in vitro biochemical characterization of SgcC3 and SgcC that catalyze chlorination and hydroxylation of SgcC2-tethered (S)-?-tyrosine and analogues in the biosynthesis of the enediyne chromophore of the chromoprotein C-1027. These protocols are applicable to mechanistic characterization and engineered exploitation of other tailoring enzymes that act on CP-tethered substrates in natural product biosynthesis and structural diversification. The ultimate goal is to use the in vitro findings to guide in vivo engineering of designer natural products. PMID:23034236

Lin, Shuangjun; Huang, Tingting; Shen, Ben

2012-01-01

3

Enzyme  

MedlinePLUS

Enzymes are complex proteins that cause a specific chemical change in all parts of the body. For ... use them. Blood clotting is another example of enzymes at work. Enzymes are needed for all body ...

4

Klotho: a novel phosphaturic substance acting as an autocrine enzyme in the renal proximal tubule  

PubMed Central

Klotho has profound effects on phosphate metabolism, but the mechanisms of how Klotho affects phosphate homeostasis is unknown. We detected Klotho in the proximal tubule cell, brush border, and urinary lumen, where phosphate homeostasis resides. Increasing Klotho in the kidney and urine chronically by transgenic overexpression or acutely by intravenous infusion caused hypophosphatemia, phosphaturia from decreased proximal phosphate reabsorption, and decreased activity and protein of the principal renal phosphate transporter NaPi-2a. The phosphaturic effect was present in FGF23-null mice, indicating a direct action distinct from Klotho’s known role as a coreceptor for FGF23. Direct inhibition of NaPi-2a by Klotho was confirmed in cultured cells and in cell-free membrane vesicles characterized by acute inhibition of transport activity followed by decreased cell surface protein. Transport inhibition can be mimicked by recombinant ?-glucuronidase and is associated with proteolytic degradation and reduced surface NaPi-2a. The inhibitory effect of Klotho on NaPi-2a was blocked by ?-glucuronidase inhibitor but not by protease inhibitor. Klotho is a novel phosphaturic substance that acts as an enzyme in the proximal tubule urinary lumen by modifying glycans, which cause decreased transporter activity, followed by proteolytic degradation and possibly internalization of NaPi-2a from the apical membrane.—Hu, M. C., Shi, M., Zhang, J., Pastor, J., Nakatani, T., Lanske, B., Shawkat Razzaque, M., Rosenblatt, K. P., Baum, M. G., Kuro-o, M., Moe, O. W. Klotho: a novel phosphaturic substance acting as an autocrine enzyme in the renal proximal tubule. PMID:20466874

Hu, Ming Chang; Shi, Mingjun; Zhang, Jianning; Pastor, Johanne; Nakatani, Teruyo; Lanske, Beate; Razzaque, M. Shawkat; Rosenblatt, Kevin P.; Baum, Michel G.; Kuro-o, Makoto; Moe, Orson W.

2010-01-01

5

Klotho: a novel phosphaturic substance acting as an autocrine enzyme in the renal proximal tubule.  

PubMed

Klotho has profound effects on phosphate metabolism, but the mechanisms of how Klotho affects phosphate homeostasis is unknown. We detected Klotho in the proximal tubule cell, brush border, and urinary lumen, where phosphate homeostasis resides. Increasing Klotho in the kidney and urine chronically by transgenic overexpression or acutely by intravenous infusion caused hypophosphatemia, phosphaturia from decreased proximal phosphate reabsorption, and decreased activity and protein of the principal renal phosphate transporter NaPi-2a. The phosphaturic effect was present in FGF23-null mice, indicating a direct action distinct from Klotho's known role as a coreceptor for FGF23. Direct inhibition of NaPi-2a by Klotho was confirmed in cultured cells and in cell-free membrane vesicles characterized by acute inhibition of transport activity followed by decreased cell surface protein. Transport inhibition can be mimicked by recombinant beta-glucuronidase and is associated with proteolytic degradation and reduced surface NaPi-2a. The inhibitory effect of Klotho on NaPi-2a was blocked by beta-glucuronidase inhibitor but not by protease inhibitor. Klotho is a novel phosphaturic substance that acts as an enzyme in the proximal tubule urinary lumen by modifying glycans, which cause decreased transporter activity, followed by proteolytic degradation and possibly internalization of NaPi-2a from the apical membrane. PMID:20466874

Hu, Ming Chang; Shi, Mingjun; Zhang, Jianning; Pastor, Johanne; Nakatani, Teruyo; Lanske, Beate; Razzaque, M Shawkat; Rosenblatt, Kevin P; Baum, Michel G; Kuro-o, Makoto; Moe, Orson W

2010-09-01

6

Fumarate Analogs Act as Allosteric Inhibitors of the Human Mitochondrial NAD(P)+-Dependent Malic Enzyme  

PubMed Central

Human mitochondrial NAD(P)+-dependent malic enzyme (m-NAD(P)-ME) is allosterically activated by the four-carbon trans dicarboxylic acid, fumarate. Previous studies have suggested that the dicarboxylic acid in a trans conformation around the carbon-carbon double bond is required for the allosteric activation of the enzyme. In this paper, the allosteric effects of fumarate analogs on m-NAD(P)-ME are investigated. Two fumarate-insensitive mutants, m-NAD(P)-ME_R67A/R91A and m-NAD(P)-ME_K57S/E59N/K73E/D102S, as well as c-NADP-ME, were used as the negative controls. Among these analogs, mesaconate, trans-aconitate, monomethyl fumarate and monoethyl fumarate were allosteric activators of the enzyme, while oxaloacetate, diethyl oxalacetate, and dimethyl fumarate were found to be allosteric inhibitors of human m-NAD(P)-ME. The IC50 value for diethyl oxalacetate was approximately 2.5 mM. This paper suggests that the allosteric inhibitors may impede the conformational change from open form to closed form and therefore inhibit m-NAD(P)-ME enzyme activity. PMID:24911153

Yang, Pai-Chun; Lin, Chi-Li; Liu, Guang-Yaw; Hung, Hui-Chih

2014-01-01

7

A natural vanishing act: the enzyme-catalyzed degradation of carbon nanomaterials.  

PubMed

Over the past three decades, revolutionary research in nanotechnology by the scientific, medical, and engineering communities has yielded a treasure trove of discoveries with diverse applications that promise to benefit humanity. With their unique electronic and mechanical properties, carbon nanomaterials (CNMs) represent a prime example of the promise of nanotechnology with applications in areas that include electronics, fuel cells, composites, and nanomedicine. Because of toxicological issues associated with CNMs, however, their full commercial potential may not be achieved. The ex vitro, in vitro, and in vivo data presented in this Account provide fundamental insights into the biopersistence of CNMs, such as carbon nanotubes and graphene, and their oxidation/biodegradation processes as catalyzed by peroxidase enzymes. We also communicate our current understanding of the mechanism for the enzymatic oxidation and biodegradation. Finally, we outline potential future directions that could enhance our mechanistic understanding of the CNM oxidation and biodegradation and could yield benefits in terms of human health and environmental safety. The conclusions presented in this Account may catalyze a rational rethinking of CNM incorporation in diverse applications. For example, armed with an understanding of how and why CNMs undergo enzyme-catalyzed oxidation and biodegradation, researchers can tailor the structure of CNMs to either promote or inhibit these processes. In nanomedical applications such as drug delivery, the incorporation of carboxylate functional groups could facilitate biodegradation of the nanomaterial after delivery of the cargo. On the other hand, in the construction of aircraft, a CNM composite should be stable to oxidizing conditions in the environment. Therefore, pristine, inert CNMs would be ideal for this application. Finally, the incorporation of CNMs with defect sites in consumer goods could provide a facile mechanism that promotes the degradation of these materials once these products reach landfills. PMID:22824066

Kotchey, Gregg P; Hasan, Saad A; Kapralov, Alexander A; Ha, Seung Han; Kim, Kang; Shvedova, Anna A; Kagan, Valerian E; Star, Alexander

2012-10-16

8

Transcriptional analysis of selected cellulose-acting enzymes encoding genes of the white-rot fungus Dichomitus squalens on spruce wood and microcrystalline cellulose.  

PubMed

The recent discovery of oxidative cellulose degradation enhancing enzymes has considerably changed the traditional concept of hydrolytic cellulose degradation. The relative expression levels of ten cellulose-acting enzyme encoding genes of the white-rot fungus Dichomitus squalens were studied on solid-state spruce wood and in microcrystalline Avicel cellulose cultures. From the cellobiohydrolase encoding genes, cel7c was detected at the highest level and showed constitutive expression whereas variable transcript levels were detected for cel7a, cel7b and cel6 in the course of four-week spruce cultivation. The cellulolytic enzyme activities detected in the liquid cultures were consistent with the transcript levels. Interestingly, the selected lytic polysaccharide monooxygenase (LPMO) encoding genes were expressed in both cultures, but showed different transcription patterns on wood compared to those in submerged microcrystalline cellulose cultures. On spruce wood, higher transcript levels were detected for the lpmos carrying cellulose binding module (CBM) than for the lpmos without CBMs. In both cultures, the expression levels of the lpmo genes were generally higher than the levels of cellobiose dehydrogenase (CDH) encoding genes. Based on the results of this work, the oxidative cellulose cleaving enzymes of D. squalens have essential role in cellulose degrading machinery of the fungus. PMID:24394946

Rytioja, Johanna; Hildén, Kristiina; Hatakka, Annele; Mäkelä, Miia R

2014-11-01

9

The Catalytic Scaffold fo the Haloalkanoic Acid Dehalogenase Enzyme Superfamily Acts as a Mold for the Trigonal Bipyramidal Transition State  

SciTech Connect

The evolution of new catalytic activities and specificities within an enzyme superfamily requires the exploration of sequence space for adaptation to a new substrate with retention of those elements required to stabilize key intermediates/transition states. Here, we propose that core residues in the large enzyme family, the haloalkanoic acid dehalogenase enzyme superfamily (HADSF) form a 'mold' in which the trigonal bipyramidal transition states formed during phosphoryl transfer are stabilized by electrostatic forces. The vanadate complex of the hexose phosphate phosphatase BT4131 from Bacteroides thetaiotaomicron VPI-5482 (HPP) determined at 1.00 Angstroms resolution via X-ray crystallography assumes a trigonal bipyramidal coordination geometry with the nucleophilic Asp-8 and one oxygen ligand at the apical position. Remarkably, the tungstate in the complex determined to 1.03 Angstroms resolution assumes the same coordination geometry. The contribution of the general acid/base residue Asp-10 in the stabilization of the trigonal bipyramidal species via hydrogen-bond formation with the apical oxygen atom is evidenced by the 1.52 Angstroms structure of the D10A mutant bound to vanadate. This structure shows a collapse of the trigonal bipyramidal geometry with displacement of the water molecule formerly occupying the apical position. Furthermore, the 1.07 Angstroms resolution structure of the D10A mutant complexed with tungstate shows the tungstate to be in a typical 'phosphate-like' tetrahedral configuration. The analysis of 12 liganded HADSF structures deposited in the protein data bank (PDB) identified stringently conserved elements that stabilize the trigonal bipyramidal transition states by engaging in favorable electrostatic interactions with the axial and equatorial atoms of the transferring phosphoryl group.

Lu,Z.; Dunaway-Mariano, D.; Allen, K.

2008-01-01

10

The catecholamine biosynthetic enzyme dopamine ?-hydroxylase (DBH): first genome-wide search positions trait-determining variants acting additively in the proximal promoter.  

PubMed

Dopamine beta-hydroxylase (DBH) is the biosynthetic enzyme catalyzing formation of norepinephrine. Changes in DBH expression or activity have been implicated in the pathogenesis of cardiovascular and neuropsychiatric disorders. Genetic determination of DBH enzymatic activity and its secretion are only incompletely understood. We began with a genome-wide association search for loci contributing to DBH activity in human plasma. Initially, in a population sample of European ancestry, we identified the proximal DBH promoter as a region harboring three common trait-determining variants (top hit rs1611115, P = 7.2 × 10(-51)). We confirmed their effects on transcription and showed that the three variants each acted additively on gene expression. Results were replicated in a population sample of Native American descent (top hit rs1611115, P = 4.1 × 10(-15)). Jointly, DBH variants accounted for 57% of DBH trait variation. We further identified a genome-wide significant SNP at the LOC338797 locus on chromosome 12 as trans-quantitative trait locus (QTL) (rs4255618, P = 4.62 × 10(-8)). Conditional analyses on DBH identified a third genomic region contributing to DBH variation: a likely cis-QTL adjacent to DBH in SARDH (rs7040170, P = 1.31 × 10(-14)) on chromosome 9q. We conclude that three common SNPs in the DBH promoter act additively to control phenotypic variation in DBH levels, and that two additional novel loci (SARDH and LOC338797) may also contribute to the expression of this catecholamine biosynthetic trait. Identification of DBH variants with strong effects makes it possible to take advantage of Mendelian randomization approaches to test causal effects of this intermediate trait on disease. PMID:24986918

Mustapic, Maja; Maihofer, Adam X; Mahata, Manjula; Chen, Yuqing; Baker, Dewleen G; O'Connor, Daniel T; Nievergelt, Caroline M

2014-12-01

11

ENZYME: Enzyme Nomenclature Database  

NSDL National Science Digital Library

Recently updated, the ENZYME: Enzyme Nomenclature Database is based mainly on recommendations by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (IUBMB) and "describes each type of characterized enzyme for which an EC (Enzyme Commission) number has been provided." An online user manual describes how to access and use the database, which may be searched by EC number, enzyme class, official description or alternative name(s), chemical compound, or cofactor. Typical returns include Names, Reaction catalyzed, Comments, Human Genetic Diseases, and a host of hyperlinked cross-references. ENZYME is provided by the Swiss Institute of Bioinformatics.

12

Catalyzed enzyme electrodes  

DOEpatents

An enzyme electrode is prepared with a composite coating on an electrical conductor. The composite coating is formed from a casting solution of a perfluorosulfonic acid polymer, an enzyme, and a carbon supported catalyst. The solution may be cast directly on the conductor surface or may be formed as a membrane and applied to the surface. The perfluorosulfonic acid ionomer formed from the casting solution provides an insoluble biocompatible protective matrix for the enzyme and acts to retain the enzyme for long term availability in the electrode structure. The carbon supported catalyst provides catalytic sites throughout the layer for the oxidation of hydrogen peroxide from the enzyme reactions. The carbon support then provides a conductive path for establishing an electrical signal to the electrical conductor. In one embodiment, the electrical conductor is a carbon cloth that permits oxygen or other gas to be introduced to the perfluorosulfonic polymer to promote the enzyme reaction independent of oxygen in the solution being tested.

Zawodzinski, Thomas A. (Los Alamos, NM); Wilson, Mahlon S. (Los Alamos, NM); Rishpon, Judith (Ramat-Aviv, IL); Gottesfeld, Shimshon (Los Alamos, NM)

1993-01-01

13

Enzyme Reactions  

NSDL National Science Digital Library

This video shows an enzyme reaction lab. The teacher demonstrates how the enzyme, catalase, reacts with hydrogen peroxide (a substrate found in cells). The teacher first demonstrates a normal enzyme reaction. He or she then goes on to show how manipulating temperature and pH will affect the reaction of an enzyme.

Minerva Deland School

2011-10-03

14

Enzyme Kinetics  

NSDL National Science Digital Library

This resrouce provides detailed protocols for performing a laboratory exercise in enzyme kinetics. The activity of enzymes are characterized both by reaction rates and the effect of different concentrations of substrates.

Carl Stiefbold (University of Oregon; )

1998-01-01

15

Enzyme Kinetics.  

ERIC Educational Resources Information Center

Conveys an appreciation of enzyme kinetic analysis by using a practical and intuitive approach. Discusses enzyme assays, kinetic models and rate laws, the kinetic constants (V, velocity, and Km, Michaels constant), evaluation of V and Km from experimental data, and enzyme inhibition. (CW)

Moe, Owen; Cornelius, Richard

1988-01-01

16

Enzyme Informatics  

PubMed Central

Over the last 50 years, sequencing, structural biology and bioinformatics have completely revolutionised biomolecular science, with millions of sequences and tens of thousands of three dimensional structures becoming available. The bioinformatics of enzymes is well served by, mostly free, online databases. BRENDA describes the chemistry, substrate specificity, kinetics, preparation and biological sources of enzymes, while KEGG is valuable for understanding enzymes and metabolic pathways. EzCatDB, SFLD and MACiE are key repositories for data on the chemical mechanisms by which enzymes operate. At the current rate of genome sequencing and manual annotation, human curation will never finish the functional annotation of the ever-expanding list of known enzymes. Hence there is an increasing need for automated annotation, though it is not yet widespread for enzyme data. In contrast, functional ontologies such as the Gene Ontology already profit from automation. Despite our growing understanding of enzyme structure and dynamics, we are only beginning to be able to design novel enzymes. One can now begin to trace the functional evolution of enzymes using phylogenetics. The ability of enzymes to perform secondary functions, albeit relatively inefficiently, gives clues as to how enzyme function evolves. Substrate promiscuity in enzymes is one example of imperfect specificity in protein-ligand interactions. Similarly, most drugs bind to more than one protein target. This may sometimes result in helpful polypharmacology as a drug modulates plural targets, but also often leads to adverse side-effects. Many cheminformatics approaches can be used to model the interactions between druglike molecules and proteins in silico. We can even use quantum chemical techniques like DFT and QM/MM to compute the structural and energetic course of enzyme catalysed chemical reaction mechanisms, including a full description of bond making and breaking. PMID:23116471

Alderson, Rosanna G.; Ferrari, Luna De; Mavridis, Lazaros; McDonagh, James L.; Mitchell, John B. O.; Nath, Neetika

2012-01-01

17

Molecular Scissors: RNA Enzymes Go Commercial  

Microsoft Academic Search

When Thomas Cech of the University of Colorado discovered in 1982 that RNA can act as an enzyme, catalyzing specific biological reactions, the result surprised molecular biologists. Only proteins, they thought, could act as enzymes. The work not only led to a Nobel Prize for Cech, it prompted prophecies of a new kind of genetic engineering - one based on

Ann Gibbons

1991-01-01

18

Enzymes, Industrial  

Technology Transfer Automated Retrieval System (TEKTRAN)

Enzymes serve key roles in numerous biotechnology processes and products that are commonly encountered in the forms of food and beverages, cleaning supplies, clothing, paper products, transportation fuels, pharmaceuticals, and monitoring devices. Enzymes can display regio- and stereo-specificity, p...

19

Soil Enzymes  

Technology Transfer Automated Retrieval System (TEKTRAN)

The functionality and resilience of natural and managed ecosystems mainly rely on the metabolic abilities of microbial communities, the main source of enzymes in soils. Enzyme mediated reactions are critical in the decomposition of organic matter, cycling of nutrients, and in the breakdown of herbic...

20

Enzyme Action  

NSDL National Science Digital Library

In this activity that can be used as a lab or demonstration, learners use Lactaid® and lactose to demonstrate the concept of enzyme action. Learners test a drop of milk and Lactaid® for the presence of glucose using glucose test paper. Learners also discover the color range of glucose test paper readings. In addition, learners construct paper models to help visualize enzyme action.

Jane Crumlish

2009-01-01

21

Glutathione degradation by the alternative pathway (DUG pathway) in Saccharomyces cerevisiae is initiated by (Dug2p-Dug3p)2 complex, a novel glutamine amidotransferase (GATase) enzyme acting on glutathione.  

PubMed

The recently identified, fungi-specific alternative pathway of glutathione degradation requires the participation of three genes, DUG1, DUG2, and DUG3. Dug1p has earlier been shown to function as a Cys-Gly-specific dipeptidase. In the present study, we describe the characterization of Dug2p and Dug3p. Dug3p has a functional glutamine amidotransferase (GATase) II domain that is catalytically important for glutathione degradation as demonstrated through mutational analysis. Dug2p, which has an N-terminal WD40 and a C-terminal M20A peptidase domain, has no peptidase activity. The previously demonstrated Dug2p-Dug3p interaction was found to be mediated through the WD40 domain of Dug2p. Dug2p was also shown to be able to homodimerize, and this was mediated by its M20A peptidase domain. In vitro reconstitution assays revealed that Dug2p and Dug3p were required together for the cleavage of glutathione into glutamate and Cys-Gly. Purification through gel filtration chromatography confirmed the formation of a Dug2p-Dug3p complex. The functional complex had a molecular weight that corresponded to (Dug2p-Dug3p)(2) in addition to higher molecular weight oligomers and displayed Michaelis-Menten kinetics. (Dug2p-Dug3p)(2) had a K(m) for glutathione of 1.2 mm, suggesting a novel GATase enzyme that acted on glutathione. Dug1p activity in glutathione degradation was found to be restricted to its Cys-Gly peptidase activity, which functioned downstream of the (Dug2p-Dug3p)(2) GATase. The DUG2 and DUG3 genes, but not DUG1, were derepressed by sulfur limitation. Based on these studies and the functioning of GATases, a mechanism is proposed for the functioning of the Dug proteins in the degradation of glutathione. PMID:22277648

Kaur, Hardeep; Ganguli, Dwaipayan; Bachhawat, Anand K

2012-03-16

22

Enzyme Reactions  

NSDL National Science Digital Library

The enzyme reaction rate activity allows students to simulate the effects of variables such as temperature and pH on the reaction rate of the enzyme catalase. This computer simulation is best used after the students have done a wet lab experiment. The value of the simulation is that it requires the students to interpret and analyze the graphical representation of data and it enables the running of mutiple experiments in a short amount of time.

Maryland Virtual High School

23

Food Enzymes  

ERIC Educational Resources Information Center

Many students view biology and chemistry as two unrelated, separate sciences; how these courses are generally taught in high schools may do little to change that impression. The study of enzymes provide a great opportunity for both biology and chemistry teachers to share with students the interdisciplinary nature of science. This article describes…

McBroom, Rachel; Oliver-Hoyo, Maria T.

2007-01-01

24

Pancreatic Enzymes  

MedlinePLUS

... the formation of toxic substances due to incomplete digestion of proteins. Increased risk for intestinal infections. Amylase Amylase breaks down carbohydrates (starch) into sugars which are more easily absorbed by the body. This ... needed for digestion. Having an insufficient amount of pancreatic enzymes is ...

25

Primary enzyme quantitation  

DOEpatents

The disclosure relates to the quantitation of a primary enzyme concentration by utilizing a substrate for the primary enzyme labeled with a second enzyme which is an indicator enzyme. Enzyme catalysis of the substrate occurs and results in release of the indicator enzyme in an amount directly proportional to the amount of primary enzyme present. By quantifying the free indicator enzyme one determines the amount of primary enzyme present.

Saunders, G.C.

1982-03-04

26

Restriction Enzymes  

NSDL National Science Digital Library

Watson and Crick's description, in 1953, of the double helical structure of the DNA molecule opened the door to a new era in biological understanding and research. Scientists, now knowing the molecular structure of the hereditary molecule, could begin both to elucidate and to manipulate its function. These new studies were, however, dependent on the discovery and use of the many enzymes that can modify or join existing DNA molecules, or aid in the synthesis of new DNA molecules. Includes background article, student activities/demonstratons, graphics, glossary and related references.

BEGIN:VCARD VERSION:2.1 FN:Pamela Peters N:Peters; Pamela ORG:Genentech, Inc. REV:2005-04-14 END:VCARD

1995-06-01

27

Acting Atoms.  

ERIC Educational Resources Information Center

Describes a fun game in which students act as electrons, protons, and neutrons. This activity is designed to help students develop a concrete understanding of the abstract concept of atomic structure. (DKM)

Farin, Susan Archie

1997-01-01

28

ACT Test  

MedlinePLUS

... Pagnani, G. et. al. (Updated 2009 May 29). Massachusetts General Hospital Activated Clotting Time performed on the Medtronic ACT PlusTM. Massachusetts General Hospital. [On-line information]. PDF available for ...

29

PROTEOLYTIC ENZYMES  

PubMed Central

1. The literature on conditions affecting the activity of proteolytic enzymes has been reviewed. 2. Experimental data on the control of the activity of trypsin, leucoprotease, papain, serum antiprotease, leucopeptidase, and pancreatic peptidase have been presented. These data indicate that: (a) The polymorphonuclearleucocytes of the cat contain abundant proteinase and peptidase active at neutral pH; those of the rabbit lack proteinase active at neutral pH. (b) Reducing agents, including several biologically important thiol-sulfhydryl compounds and ascorbic acid, inhibit the activity of leucoprotease and trypsin. For each reductant the degree of inhibition is proportional to the reducing capacity of the medium. (c) p-Aminobenzoic acid, sulfonamides (especially sulfathiazole), and many diphenyl sulfones inhibit the activity of leucoprotease. (d) Serum, plasma, several heavy metals, ammonium salts, asparagine, thiourea, heparin, glutamic acid, tyrothricin, calcium chloride, and bile salts and bile acids also inhibit the activity of leucoprotease, and in most cases of trypsin too. (e) Preparations of tryptic digests of proteins, and egg white trypsin inhibitor, inhibit trypsin to a much greater degree than leucoprotease. (f) Mild oxidizing agents increase the activity of leucoprotease and trypsin. (g) Oxidizing agents and some inhibitors of sulfhydryl groups inhibit the antiproteolytic activity of the serum. It is suggested that serum antiprotease may consist (chiefly) of reducing agents, including thiol-sulfhydryl peptides which exert their antiproteolytic activity by virtue of the presence of sulfhydryl groups. (h) The antiproteolytic activity of the serum is progressively weakened by exposure to a hydrogen ion concentration below pH 6.5 or above pH 9.7. Because of this the pH optima of leucoprotease and trypsin are shifted in the presence of serum from pH of 7 and 8 to pH of 6 to 6.5, and the range of activity of these enzymes is slightly widened, in both acid and alkaline reactions. (i) Reducing agents increase the activity of leucopeptidase and pancreatic peptidase. Serum, sulfathiazole, and thiourea have little or no effect. 3. The significance of the oxidation-reduction system in the control of the activity of leucoprotease, trypsin, serum antiprotease, leucopeptidase, and pancreatic peptidase has been emphasized. PMID:19873458

Grob, David

1946-01-01

30

Balancing Act  

ERIC Educational Resources Information Center

For some administrators and planners, designing and building education facilities may sometimes seem like a circus act--trying to project a persona of competence and confidence while juggling dozens of issues. Meanwhile, the audience--students, staff members and taxpayers--watch and wait with anticipation in hopes of getting what they paid for and…

Kennedy, Mike

2007-01-01

31

BIOCHEMISTRY: Remote Enzyme Microsurgery  

NSDL National Science Digital Library

Enzymes enhance the rate of chemical reactions. Useful electrophiles for use in these reactions are few in the standard amino acid building blocks of enzymes. This perspective discusses "enzyme microsurgery" for construction of an electrophile.

J. Martin Bollinger (Pennsylvania State University; Department of Chemistry)

2010-03-12

32

Acting Out  

NSDL National Science Digital Library

This activity (on pages 21-32 of PDF) has learners act out several classic brain teasers. Instead of moving checkers or pennies around on a table, learners play the role of the different pieces of the puzzle, and have to move themselves around. The lesson plan includes printable pictures of different characters than can be worn by the learners. Answers to the puzzles are provided so the facilitator can guide learners towards the solution.

OMSI

2008-01-01

33

Enzyme kinetics at high enzyme concentration  

Microsoft Academic Search

We re-visit previous analyses of the classical Michaelis-Menten substrate-enzyme reaction and, with the aid of the reverse\\u000a quasi-steady-state assumption, we challenge the approximation d[C]\\/dt ? 0 for the basic enzyme reaction at high enzyme concentration. For the first time, an approximate solution for the concentrations\\u000a of the reactants uniformly valid in time is reported. Numerical simulations are presented to verify

S. Schnell; P. K. Maini

2000-01-01

34

Insolubilization process increases enzyme stability  

NASA Technical Reports Server (NTRS)

Enzymes complexed with polymeric matrices contain properties suggesting application to enzyme-controlled reactions. Stability of insolubilized enzyme derivatives is markedly greater than that of soluble enzymes and physical form of insolubilized enzymes is useful in column and batch processes.

Billingham, J.; Lyn, J.

1971-01-01

35

Introduction Pancreatic cholesterol esterase (CEase), an enzyme,  

E-print Network

535 Introduction Pancreatic cholesterol esterase (CEase), an enzyme, which is also known as bile cholesterol esters, fat-soluble vitamins, triglycerides, and phospholipids.1,2 CEase is secreted from cholesterol level.6,7 Therefore, CEase may function in these roles and act as cholesterol transfer protein

Lee, Keun Woo

36

Inhibition Enzyme Sensor for Nicotine, Nicotinamide and Nicotinic Acid Determination  

NASA Astrophysics Data System (ADS)

Nicotine, nicotinic acid and nicotinamide were tested in pharmaceutical products using an inhibition enzyme sensor consisting of a hydrogen peroxide amperometric electrode coupled to a functionalised nylon membrane chemically bonding the enzymes butyrylcholinesterase and choline oxidase; a butyrylcholine standard solution in glycine buffer acted as substrate.

Campanella, L.; Cocco, R.; Favero, G.; Sammartino, M. P.; Tomassetti, M.

2000-12-01

37

Enzyme-Coated Carbon Nanotubes as Single-Molecule Biosensors  

E-print Network

Enzyme-Coated Carbon Nanotubes as Single-Molecule Biosensors Koen Besteman, Jeong-O Lee, Frank G. M. The enzyme-coated tube is found to act as a pH sensor with large and reversible changes in conductance upon

Dekker, Cees

38

FERULOYL ESTERASE - A KEY ENZYME IN BIOMASS DEGRADATION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Feruloyl esterase forms a part of the enzyme complex that acts collectively and synergistically to completely hydrolyze xylan to its monomers. The enzyme has found potential uses in a wide variety of applications of interest to the agri-food and pharmaceutical industries. This review describes the...

39

Flow-Cell Fibre-Optic Enzyme Sensor for Phenols  

Microsoft Academic Search

A solid-state fibre-optic luminescent oxygen sensor was used for flow-through measurements. It acts as a transducer in a new flow-cell enzyme sensor arrangement. This arrangement comprises a flow path, sample injector, microcolumn with the immobilized enzyme, oxygen membrane and fibre-optic connector joined together to form an integral unit. Laccase enzyme was used as a recognition system which provided specific oxidation

Dmitry B. Papkovsky; Andrey L. Ghindilis; Ilya N. Kurochkin

1993-01-01

40

Enzyme responsive acetaminophen hydrogels  

E-print Network

Utilization of enzyme catalysis as a tool to disassemble self-assembled hydrogels to control the release encapsulated drug provides an opportunity to design a wide range of enzyme-specific low-molecular-weight hydrogelators ...

Vemula, Praveen

41

Act resilient.  

PubMed

Attendees have reported changing from being fearful to serene, from listless to energized, from disengaged to connected, and becoming markedly less anxious in a few weeks. Anecdotally, self-reported stress levels have been reduced by over 50% after just one class. Attendees learn not to be afraid of their feelings by working with emotions in a playful manner. When a person can act angry, but separate himself from his personal story, the emotional energy exists in a separate form that is not attached to specific events, and can be more easily dealt with and neutralized. Attendees are taught to "take out the emotional trash" through expressive comedy. They become less intimated by their own emotional intensity and triggers as they learn how even metaphorical buckets of anger, shame, guilt and hurt can be emotionally emptied. The added benefit is that this is accomplished without the disclosure of personal information of the requirement to reexperience past pain which can trigger its own cascade of stress. PMID:24706248

Joseph, Genie; Bice-Stephens, Wynona

2014-01-01

42

Novel enzymes for the degradation of cellulose  

PubMed Central

The bulk terrestrial biomass resource in a future bio-economy will be lignocellulosic biomass, which is recalcitrant and challenging to process. Enzymatic conversion of polysaccharides in the lignocellulosic biomass will be a key technology in future biorefineries and this technology is currently the subject of intensive research. We describe recent developments in enzyme technology for conversion of cellulose, the most abundant, homogeneous and recalcitrant polysaccharide in lignocellulosic biomass. In particular, we focus on a recently discovered new type of enzymes currently classified as CBM33 and GH61 that catalyze oxidative cleavage of polysaccharides. These enzymes promote the efficiency of classical hydrolytic enzymes (cellulases) by acting on the surfaces of the insoluble substrate, where they introduce chain breaks in the polysaccharide chains, without the need of first “extracting” these chains from their crystalline matrix. PMID:22747961

2012-01-01

43

Enzyme Nomenclature 1998  

NSDL National Science Digital Library

The Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB) has made available this online version of Enzyme Nomenclature 1998. NC-IUBMB is currently accepting recommendations for enzyme nomenclature of Oxidoreductases, Transferases, Hydrolases, Lyases, Isomerases, and Ligases. A list of approved peptidases is available. December 31, 1998 is the deadline for submission of enzyme nomenclature recommendations.

International Union of Biochemistry and Molecular Biology. Nomenclature Committee.

1998-01-01

44

Developments in Enzyme Technology.  

ERIC Educational Resources Information Center

Enzyme technology has a well-established industrial base, with applications that have survived competition. The most prominent applications of enzymes in biotechnology are examined with an explanation of some theoretical background. Topics include extending an enzyme's useful life, partition and diffusion, industrial uses, and therapeutic uses.…

Chaplin, M. F.

1984-01-01

45

Profiling the orphan enzymes.  

PubMed

The emergence of Next Generation Sequencing generates an incredible amount of sequence and great potential for new enzyme discovery. Despite this huge amount of data and the profusion of bioinformatic methods for function prediction, a large part of known enzyme activities is still lacking an associated protein sequence. These particular activities are called "orphan enzymes". The present review proposes an update of previous surveys on orphan enzymes by mining the current content of public databases. While the percentage of orphan enzyme activities has decreased from 38% to 22% in ten years, there are still more than 1,000 orphans among the 5,000 entries of the Enzyme Commission (EC) classification. Taking into account all the reactions present in metabolic databases, this proportion dramatically increases to reach nearly 50% of orphans and many of them are not associated to a known pathway. We extended our survey to "local orphan enzymes" that are activities which have no representative sequence in a given clade, but have at least one in organisms belonging to other clades. We observe an important bias in Archaea and find that in general more than 30% of the EC activities have incomplete sequence information in at least one superkingdom. To estimate if candidate proteins for local orphans could be retrieved by homology search, we applied a simple strategy based on the PRIAM software and noticed that candidates may be proposed for an important fraction of local orphan enzymes. Finally, by studying relation between protein domains and catalyzed activities, it appears that newly discovered enzymes are mostly associated with already known enzyme domains. Thus, the exploration of the promiscuity and the multifunctional aspect of known enzyme families may solve part of the orphan enzyme issue. We conclude this review with a presentation of recent initiatives in finding proteins for orphan enzymes and in extending the enzyme world by the discovery of new activities. PMID:24906382

Sorokina, Maria; Stam, Mark; Médigue, Claudine; Lespinet, Olivier; Vallenet, David

2014-01-01

46

Profiling the orphan enzymes  

PubMed Central

The emergence of Next Generation Sequencing generates an incredible amount of sequence and great potential for new enzyme discovery. Despite this huge amount of data and the profusion of bioinformatic methods for function prediction, a large part of known enzyme activities is still lacking an associated protein sequence. These particular activities are called “orphan enzymes”. The present review proposes an update of previous surveys on orphan enzymes by mining the current content of public databases. While the percentage of orphan enzyme activities has decreased from 38% to 22% in ten years, there are still more than 1,000 orphans among the 5,000 entries of the Enzyme Commission (EC) classification. Taking into account all the reactions present in metabolic databases, this proportion dramatically increases to reach nearly 50% of orphans and many of them are not associated to a known pathway. We extended our survey to “local orphan enzymes” that are activities which have no representative sequence in a given clade, but have at least one in organisms belonging to other clades. We observe an important bias in Archaea and find that in general more than 30% of the EC activities have incomplete sequence information in at least one superkingdom. To estimate if candidate proteins for local orphans could be retrieved by homology search, we applied a simple strategy based on the PRIAM software and noticed that candidates may be proposed for an important fraction of local orphan enzymes. Finally, by studying relation between protein domains and catalyzed activities, it appears that newly discovered enzymes are mostly associated with already known enzyme domains. Thus, the exploration of the promiscuity and the multifunctional aspect of known enzyme families may solve part of the orphan enzyme issue. We conclude this review with a presentation of recent initiatives in finding proteins for orphan enzymes and in extending the enzyme world by the discovery of new activities. Reviewers This article was reviewed by Michael Galperin, Daniel Haft and Daniel Kahn. PMID:24906382

2014-01-01

47

Fluorimetric assay of phospholipase A acting on biomembrane phospholipids.  

PubMed

A sensitive phospholipase A assay suitable for organelle activities is described. Activation of the enzyme produces an increase in membrane lysophospholipids. The amino groups of extracted lipids were derivatized with 4-fluoro-7-nitrobenzo-2-oxa-1,3-diazole and the amounts of phosphatidylethanolamine and its lysoform were quantitated using HPLC equipped with a SiO2 column and a fluorescence detector. The procedure was tested with porcine enzyme acting on liposomes and mitochondria, and with endogenous mitochondrial enzyme. PMID:2487787

Saris, N E; Somerharju, P

1989-01-01

48

[Pseudodeficiency of lysosomal enzymes].  

PubMed

Genetically determined enzyme deficiency causing failure of the lysosomal apparatus is called lysosomal disease. In normal cell the activity of lysosomal enzymes exceeds many times the requirements of the cell. In some individuals due to gene mutation the activity of an intracellular enzyme is only slightly higher than in patients with lysosomal disease but much lower than in the general population, although without evident metabolic and clinical consequences. This situation is called enzyme pseudodeficiency. As yet cases have been reported of the pseudodeficiency of beta-galactocerebrosidase, beta-glucoronidase, beta-glucosidase, beta-hexosoaminidase A and arylosulfatase A. The character of the mutation is called in the case of the two last enzymes and a laboratory method is available for differentiation of pseudodeficiency from the actual lysosomal disease. It is not known whether in pseudodeficiency of an enzyme clinical manifestations could appear in older age. PMID:7596481

Czartoryska, B

1995-01-01

49

Rational enzyme redesign  

SciTech Connect

Protein engineering is first a means of elucidating structure-function relations in an enzyme, and second, a means of changing a protein to make it serve a different, but generally related, purpose. In principle, one may change the functional characteristics of an enzyme by altering its substrate specificity, kinetics, optimum range of activity, and chemical mechanism. Obviously one cannot make all possible combinations of amino acid changes for even the smallest enzyme, so the essential question is which changes to make. The intent of rational protein/enzyme redesign is to alter a protein/enzyme in a timely and premeditated fashion. This article provides an outline of the process of rational enzyme redesign.

Ornstein, R.L.

1994-05-01

50

Pancreatic enzyme replacement  

Microsoft Academic Search

The effect of the addition of sodium bicarbonate, aluminum hydroxide, magnesium hydroxide, calcium carbonate, or cimetidine to supplemental pancreatic enzyme therapy was investigated in patients with severe exocrine pancreatic insufficiency. Steatorrhea was reduced with the administration of three enzyme tablets with meals (73 vs 29 g\\/24 hr). The coadministration of enzyme tablets with either sodium bicarbonate (16.6 g\\/24 hr,P=0.08), or

David Y. Graham

1982-01-01

51

A Hands-On Classroom Simulation to Demonstrate Concepts in Enzyme Kinetics  

ERIC Educational Resources Information Center

A classroom exercise is described to introduce enzyme kinetics in an undergraduate biochemistry or chemistry course. The exercise is a simulation in which a student acts as an enzyme that "catalyzes" the unscrewing of a nut from a bolt. With other students assisting, the student enzyme carries out reactions with bolt-nut substrates under different…

Junker, Matthew

2010-01-01

52

Influencing Enzymes: A Lesson on Enzyme Reactions  

NSDL National Science Digital Library

This teaching resource was developed by a K-12 science teacher in the American Physiological SocietyÂ?s 2007 Frontiers in Physiology Program. For more information on this program, please visit www.frontiersinphys.org. Students will investigate the catabolic properties of the enzyme amylase and its role in digestion of breaking down starch molecules. Prior to this activity, students should be able to identify the structural and functional properties of carbohydrates and proteins. Upon completion of this activity, students will be able to predict the effect of different environments on enzyme activity.

Camia Steinmann (Clear Creek High School)

2007-08-01

53

Restriction Enzyme Mapping Lab  

NSDL National Science Digital Library

This laboratory activity, by the Biotechnology Education and Training Sequence Investment (BETSI) project at Southwestern College, walks students and educators through the procedure of restriction enzyme mapping. Restriction enzymes are found in bacteria and "cleave the double helix of DNA at specific places." This activity, which is broken up into two parts, allows students to observe this process by presenting specific procedure steps and illustrations to guide them. There is also a worksheet for students to complete: Analysis of a Restriction Enzyme Digest of a Plasmid. This is a helpful activity for any biotechnology classroom to give students hands-on experiences with enzymes and the reconstruction of recombinant DNA molecules.

54

Dissipative Dynamics of Enzymes  

NASA Astrophysics Data System (ADS)

We explore enzyme conformational dynamics at sub-Ĺ resolution, specifically, temperature effects. The ensemble-averaged mechanical response of the folded enzyme is viscoelastic in the whole temperature range between the warm and cold denaturation transitions. The dissipation parameter ? of the viscoelastic description decreases by a factor of 2 as the temperature is raised from 10 to 45 °C ; the elastic parameter K shows a similar decrease. Thus, when probed dynamically, the enzyme softens for increasing temperature. Equilibrium mechanical experiments with the DNA spring (and a different enzyme) also show, qualitatively, a small softening for increasing temperature.

Ariyaratne, Amila; Wu, Chenhao; Tseng, Chiao-Yu; Zocchi, Giovanni

2014-11-01

55

Food and feed enzymes.  

PubMed

Humans have benefited from the unique catalytic properties of enzymes, in particular for food production, for thousands of years. Prominent examples include the production of fermented alcoholic beverages, such as beer and wine, as well as bakery and dairy products. The chapter reviews the historic background of the development of modern enzyme technology and provides an overview of the industrial food and feed enzymes currently available on the world market. The chapter highlights enzyme applications for the improvement of resource efficiency, the biopreservation of food, and the treatment of food intolerances. Further topics address the improvement of food safety and food quality. PMID:23873095

Fraatz, Marco Alexander; Rühl, Martin; Zorn, Holger

2014-01-01

56

Molecular scissors: RNA enzymes go commercial  

SciTech Connect

When Thomas Cech of the University of Colorado discovered in 1982 that RNA can act as an enzyme, catalyzing specific biological reactions, the result surprised molecular biologists. Only proteins, they thought, could act as enzymes. The work not only led to a Nobel Prize for Cech, it prompted prophecies of a new kind of genetic engineering - one based on RNA instead of the conventional DNA. Foreign governments launched research efforts, and researchers scrambled to file patents. The stakes were so high that American and Australian researchers became embroiled in a dispute over patent rights for catalytic RNA. Last week the US Patent Office awarded Cech and the University of Colorado an unusually broad patent for the use and synthesis of enzymatic RNA - also known as ribozymes. The significance of the patent stems from Cech's unexpected observation that preribosomal RNA can cut and splice itself, removing sequences not needed for biological function.

Gibbons, A.

1991-02-01

57

Enzyme Database - BRENDA  

NSDL National Science Digital Library

BRENDA is the main collection of enzyme functional data available to the scientific community. It is available free of charge for via the internet (www.brenda-enzymes.info) and as an in-house database for commercial users (requests to our distributor Biobase).

Institute of Biochemistry and Bioinformatics at the Technical University of Braunschweig, Germany

58

Lignin-Degrading Enzymes  

Microsoft Academic Search

The substantial potential applications of lignin-degrading microbes and enzymes have spurred research on lignin biodegradation in recent years. As described here, that research has led to the discovery in the basidiomycete Phanerochaete chrysosporium of the first lignin-degrading enzymes and elucidation of their mode of action. A family of powerful extracellular peroxidase isoenzymes has been the focus of most investigations. The

T. K. Kirk

1987-01-01

59

Enzyme-Catalyzed Processes in Organic Solvents  

Microsoft Academic Search

Three different lipases (porcine pancreatic, yeast, and mold) can vigorously act as catalysts in a number of nearly anhydrous organic solvents. Various transesterification reactions catalyzed by porcine pancreatic lipase in hexane obey Michaelis-Menten kinetics. The dependence of the catalytic activity of the enzyme in organic media on the pH of the aqueous solution from which it was recovered is bell-shaped,

Aleksey Zaks; Alexander M. Klibanov

1985-01-01

60

Industrial Enzymes and Biocatalysis  

NASA Astrophysics Data System (ADS)

All life processes are the result of enzyme activity. In fact, life itself, whether plant or animal, involves a complex network of enzymatic reactions. An enzyme is a protein that is synthesized in a living cell. It catalyzes a thermodynamically possible reaction so that the rate of the reaction is compatible with the numerous biochemical processes essential for the growth and maintenance of a cell. The synthesis of an enzyme thus is under tight metabolic regulations and controls that can be genetically or environmentally manipulated sometimes to cause the overproduction of an enzyme by the cell. An enzyme, like chemical catalysts, in no way modifies the equilibrium constant or the free energy change of a reaction.

McAuliffe, Joseph C.; Aehle, Wolfgang; Whited, Gregory M.; Ward, Donald E.

61

Cellulose degradation by oxidative enzymes  

PubMed Central

Enzymatic degradation of plant biomass has attracted intensive research interest for the production of economically viable biofuels. Here we present an overview of the recent findings on biocatalysts implicated in the oxidative cleavage of cellulose, including polysaccharide monooxygenases (PMOs or LPMOs which stands for lytic PMOs), cellobiose dehydrogenases (CDHs) and members of carbohydrate-binding module family 33 (CBM33). PMOs, a novel class of enzymes previously termed GH61s, boost the efficiency of common cellulases resulting in increased hydrolysis yields while lowering the protein loading needed. They act on the crystalline part of cellulose by generating oxidized and non-oxidized chain ends. An external electron donor is required for boosting the activity of PMOs. We discuss recent findings concerning their mechanism of action and identify issues and questions to be addressed in the future. PMID:24688656

Dimarogona, Maria; Topakas, Evangelos; Christakopoulos, Paul

2012-01-01

62

Enzyme encapsulated hollow silica nanospheres for intracellular biocatalysis.  

PubMed

Hollow silica nanospheres (HSN) with low densities, large interior spaces and permeable silica shells are suitable for loading enzymes in the cavity to carry out intracellular biocatalysis. The porous shell can protect the encapsulated enzymes against proteolysis and attenuate immunological response. We developed a microemulsion-templating method for confining horseradish peroxidase (HRP) in the cavity of HSN. This simple one-pot enzyme encapsulation method allows entrapping of the enzyme, which retains high catalytic activity. Compared with HRP supported on solid silica spheres, HRP@HSN with thin porous silica shells displayed better enzyme activity. The small HRP@HSN (?50 nm in diameter), giving satisfactory catalytic activity, can act as an intracellular catalyst for the oxidation of the prodrug indole-3-acetic acid to produce toxic free radicals for killing cancer cells. We envision this kind of hollow nanosystem could encapsulate multiple enzymes or other synergistic drugs and function as therapeutic nanoreactors. PMID:24694065

Chang, Feng-Peng; Hung, Yann; Chang, Jen-Hsuan; Lin, Chen-Han; Mou, Chung-Yuan

2014-05-14

63

Chondroitinase: A promising therapeutic enzyme.  

PubMed

Abstract Even after 20 years of granting orphan status for chondroitinase by US FDA, there is no visible outcome in terms of clinical use. The reasons are many. One of them could be lack of awareness regarding the biological application of the enzyme. The biological activity of chondroitinase is due to its ability to act on chondroitin sulfate proteoglycans (CSPGs). CSPGs are needed for normal functioning of the body. An increase or decrease in the level of CSPGs results in various pathological conditions. Chondroitinase is useful in conditions where there is an increase in the level of CSPGs, namely spinal cord injury, vitreous attachment and cancer. Over the last decade, various animal studies showed that chondroitinase could be a good drug candidate. Research focusing on developing a suitable carrier system for delivering chondroitinase needs to be carried out so that pharmacological activity observed in vitro and preclinical studies could be translated to clinical use. Further studies on distribution of chondroitinase as well need to be focused so that chondroitinase with desired attributes could be discovered. The present review article discusses about various biological applications of chondroitinase, drug delivery systems to deliver the enzyme and distribution of chondroitinase among microbes. PMID:25319196

Kasinathan, Narayanan; Volety, Subrahmanyam M; Josyula, Venkata Rao

2014-10-16

64

Commercial production of microbial enzymes  

SciTech Connect

The advantages and uses of industrially produced microbial enzymes are described. The processes involved in the production of these enzymes, cultivation techniques, enzyme extraction, enzyme purification and immobilization are outlined. Both the history of enzyme technology and its future development are discussed.

Munro, I.G.

1985-01-01

65

Congenital erythrocyte enzyme deficiencies.  

PubMed

Congenital hemolytic anemias resulting from PK, PFK, and G6PD enzyme deficiencies have been reported in domestic animals. Dogs with PFK deficiency may have episodes of intravascular hemolysis with hemoglobinuria in addition to a persistent compensated hemolytic anemia. Patients with mild G6PD deficiency are not anemic but may show increased susceptibility to oxidant-induced erythrocyte injury. Persistent methemoglobinemia has been reported in dogs and cats with methemoglobin reductase enzyme deficiency. Affected animals have cyanotic-appearing mucous membranes but show no or only mild clinical signs attributable to hypoxemia. Enzyme assays are usually done after acquired causes of hemolytic anemia and methemoglobinemia have been ruled out. PMID:8863387

Harvey, J W

1996-09-01

66

Emerging bacterial enzyme targets.  

PubMed

The treatment of bacterial infections is increasingly complicated by the ability of bacteria to develop resistance to antimicrobial agents, as well as by the emergence of new pathogens with the potential for rapid global spread. Thus, there is a critical need for novel antibacterial agents and new strategies to advance the drug discovery process. In the post-genomic era, comparative genomics, functional genomics and proteomics will play important roles in identifying new enzyme targets for the discovery of novel antibacterial agents. This review will discuss bacterial enzyme targets, specifically focusing on enzymes involved in fatty acid and cell wall biosynthesis. PMID:17328230

Su, Zhengding; Honek, John F

2007-02-01

67

Enzyme nanoband electrodes  

SciTech Connect

Enzyme nanoelectrodes have been constructed by immobilizing glucose oxidase, alcohol oxidase or tyrosinase onto ultrathin carbon films (of 35-50 nm thickness). The enzyme immobilization is accomplished via entrapment within electropolymerized poly(o-phenylenediamine) coatings. Cyclic voltammetry and controlled-potential amperometry are used to characterize the performance of the new nanoscopic biosensors under different preparation and operation conditions. The resulting electrodes offer convenient and rapid measurements of millimolar substrate concentrations, and (to the best of the authors' knowledge) are the smallest enzyme probes reported to date. 10 refs., 7 figs.

Wang, J.; Naser, N. (New Mexico State Univ., Las Cruces (United States)); Renschler, C.L. (Sandia National Labs., Albuquerque, NM (United States))

1993-07-01

68

Enzyme catalysed tandem reactions.  

PubMed

To transfer to the laboratory, the excellent efficiency shown by enzymes in Nature, biocatalysis, had to mimic several synthetic strategies used by the living organisms. Biosynthetic pathways are examples of tandem catalysis and may be assimilated in the biocatalysis field for the use of isolated multi-enzyme systems in the homogeneous phase. The concurrent action of several enzymes that work sequentially presents extraordinary advantages from the synthetic point of view, since it permits a reversible process to become irreversible, to shift the equilibrium reaction in such a way that enantiopure compounds can be obtained from prochiral or racemic substrates, reduce or eliminate problems due to product inhibition or prevent the shortage of substrates by dilution or degradation in the bulk media, etc. In this review we want to illustrate the developments of recent studies involving in vitro multi-enzyme reactions for the synthesis of different classes of organic compounds. PMID:23490810

Oroz-Guinea, Isabel; García-Junceda, Eduardo

2013-04-01

69

RNA as an Enzyme.  

ERIC Educational Resources Information Center

Reviews current findings that explain RNA's function as an enzyme in addition to being an informational molecule. Highlights recent research efforts and notes changes in the information base on RNA activity. Includes models and diagrams of RNA activity. (ML)

Cech, Thomas R.

1986-01-01

70

Enzyme inhibition by antibodies.  

PubMed

The interest in the inhibition of enzymes by their specific antibodies stems mainly from the fact that these systems can serve as suitable models in the study of neutralization of biologically active molecules in general. The interaction of enzymes with their specific antibodies generally leads to a reduction in their enzymatic activity. The mechanism of this inhibition is rarely a direct combination of the antibodies with the catalytic site, but is rather due to steric hindrance, namely, barring the access to the active site. In several systems the mechanism of the antibody effect is by conformational changes which it induces on the enzyme. In these cases, the interaction with the antibody may result either in inhibition or in enhancement of the enzymatic activity. In every instance, however, the effect of the antibody is dependent on its narrow specificity, namely, on the regions of the enzyme to which it is directed. The extent of inhibition or enhancement is, therefore, a reflection of the nature and distribution of the various antigenic determinants on the enzyme molecule. Antibodies specific exclusively to defined regions of an enzyme molecule can be prepared. This has been performed for both lysozyme and staphylococcal nuclease by two procedures: a) Selective separation of the relevant antibodies from the anti-enzyme serum by an immunoadsorbent containing a particular immunologically active fragment of the enzyme. b) The use of an isolated antigenic fragment of the enzyme, or a conjugate of it, for immunization. The antibodies thus prepared, specific toward a unique defined region of the lysozyme molecule (residues 60-83, denoted "loop") recognize the structural conformation of the fragment and are reactive with the intact enzyme molecule. Furthermore, a chemically synthesized loop-like derivative was proved immunologically identical with the natural fragment, and when forming a part of a completely synthetic conjugate, elicited conformation-specific antibodies, reactive with native lysozyme. These findings are relevant to the topic of an immunological approach to fertility control from two different viewpoints: In the first place they are informative regarding the specific inhibition by antibodies of sperm enzymes which partake in the fertilization process. Secondly, they encourage the synthetic approach for induction of an immune response toward hormones which are crucial in fertilization or implantation. PMID:47683

Arnon, R

1975-01-01

71

Enzymes and Their Functions  

NSDL National Science Digital Library

In this module, developed as part of Cornell's Learning Initiative in Medicine and Bioengineering (CLIMB), students will learn about enzymes and how their activities are affected by different environmental factors. Following an introductory activity, students will conduct an experiment using amylase (enzyme) and starch (substrate) as an example. This module includes a teacher's guide with learning objectives and classroom activities; student activity sheets are included. CLIMB is part of the NSF GK-12 program.

CLIMB: Cornell's Learning Initiative in Medicine and Bioengineering

72

Overproduction of ligninolytic enzymes  

SciTech Connect

Methods, compositions, and systems for overproducing ligninolytic enzymes from the basidiomycetous fungus are described herein. As described, the method can include incubating a fungal strain of Cerrena unicolor IBB 303 in a fermentation system having growth medium which includes lignocellulosic material and then cultivating the fungal strain in the fermentation system under conditions wherein the fungus expresses the ligninolytic enzymes. In some cases, the lignocellulosic material is mandarin peel, ethanol production residue, walnut pericarp, wheat bran, wheat straw, or banana peel.

Elisashvili, Vladimir; Kachlishvili, Eva; Torok, Tamas

2014-06-17

73

Multi-enzyme kinetic analysis of glycolipid biosynthesis  

Microsoft Academic Search

Gangliosides are acidic glycosphingolipids synthesized sequentially by a series of glycosyltransferases acting in parallel biosynthetic pathways. While most glycosyltransferases are highly specific, some, however, may catalyze equivalent steps in each pathway using different gangliosides as substrates (e.g. N-acetylgalactosaminyltransferase, sialyltransferase-IV). A multi-enzyme kinetic analysis was developed on the condition that serial enzymatic reactions operate below substrate saturation. A multi-enzyme kinetic analysis

Erhard Bieberich; Robert K Yu

1999-01-01

74

Aminoglycoside Modifying Enzymes  

PubMed Central

Aminoglycosides have been an essential component of the armamentarium in the treatment of life-threatening infections. Unfortunately, their efficacy has been reduced by the surge and dissemination of resistance. In some cases the levels of resistance reached the point that rendered them virtually useless. Among many known mechanisms of resistance to aminoglycosides, enzymatic modification is the most prevalent in the clinical setting. Aminoglycoside modifying enzymes catalyze the modification at different ?OH or ?NH2 groups of the 2-deoxystreptamine nucleus or the sugar moieties and can be nucleotidyltranferases, phosphotransferases, or acetyltransferases. The number of aminoglycoside modifying enzymes identified to date as well as the genetic environments where the coding genes are located is impressive and there is virtually no bacteria that is unable to support enzymatic resistance to aminoglycosides. Aside from the development of new aminoglycosides refractory to as many as possible modifying enzymes there are currently two main strategies being pursued to overcome the action of aminoglycoside modifying enzymes. Their successful development would extend the useful life of existing antibiotics that have proven effective in the treatment of infections. These strategies consist of the development of inhibitors of the enzymatic action or of the expression of the modifying enzymes. PMID:20833577

Ramirez, Maria S.; Tolmasky, Marcelo E.

2010-01-01

75

Sulfite-oxidizing enzymes.  

PubMed

Sulfite-oxidizing enzymes (SOEs) are molybdenum enzymes that exist in almost all forms of life where they carry out important functions in protecting cells and organisms against sulfite-induced damage. Due to their nearly ubiquitous presence in living cells, these enzymes can be assumed to be evolutionarily ancient, and this is reflected in the fact that the basic domain architecture and fold structure of all sulfite-oxidizing enzymes studied so far are similar. The Mo centers of all SOEs have five-coordinate square pyramidal coordination geometry, which incorporates a pyranopterin dithiolene cofactor. However, significant differences exist in the quaternary structure of the enzymes, as well as in the kinetic properties and the nature of the electron acceptors used. In addition, some SOEs also contain an integral heme group that participates in the overall catalytic cycle. Catalytic turnover involves the paramagnetic Mo(V) oxidation state, and EPR spectroscopy, especially high-resolution pulsed EPR spectroscopy, provides detailed information about the molecular and electronic structure of the Mo center and the Mo-based sulfite oxidation reaction. PMID:25261289

Kappler, Ulrike; Enemark, John H

2015-03-01

76

Recovery Act Milestones  

SciTech Connect

Every 100 days, the Department of Energy is held accountable for a progress report on the American Recovery and Reinvestment Act. Update at 200 days, hosted by Matt Rogers, Senior Advisor to Secretary Steven Chu for Recovery Act Implementation.

Rogers, Matt

2009-01-01

77

ACTS Aeronautical Experiments  

NASA Technical Reports Server (NTRS)

This paper discusses a series of aeronautical experiments that utilize the advanced communication technology satellite (ACTS). As part of the ongoing effort to investigate commercial applications of ACTS technologies, NASA's Jet Propulsion Laboratory and various industry/government partners have developed a series of experiments that utilize the ACTS mobile terminal (AMT) and the broadband aeronautical terminal to investigate aeronautical uses of the ACTS. This paper discusses these experiments including the experiment configurations, technologies, results and future implications.

Agan, Martin J.; Nakamura, Daniel I.; Campbell, Alan D.; Sternowski, Robert H.; Whiting, Wendy A.; Shameson, Leon

1996-01-01

78

The ENZYME database in 2000  

Microsoft Academic Search

The ENZYME database is a repository of information related to the nomenclature of enzymes. In recent years it has became an indispensable resource for the development of metabolic databases. The current version contains information on 3705 enzymes. It is available through the ExPASy WWW server (http:\\/\\/www. expasy.ch\\/enzyme\\/ ).

Amos Bairoch

2000-01-01

79

Forgetting ACT UP  

ERIC Educational Resources Information Center

When ACT UP is remembered as the pinnacle of postmodern activism, other forms and forums of activism that were taking place during that time--practices that were linked, related, just modern, in dialogue or even opposition to ACT UP's "confrontational activism"--are forgotten. In its time, ACT UP was embedded in New York City, and a larger world,…

Juhasz, Alexandra

2012-01-01

80

Fun with Enzymes  

NSDL National Science Digital Library

In this activity, the high school students will design and carry out a procedure to observe and understand how enzymatic reactions are affected by different pH levels, different temperatures, and various substrate and enzyme concentrations. This lab can fit in nicely with a unit on biochemistry or macromolecules. Upon completion of this activity, students will be able to understand how pH, temperature and concentration affect the rate of a reaction, make solutions of different enzyme and/or substrate concentrations, and understand the importance of physiological pH and enzymes. This teaching resource was developed by a K-12 science teacher in the American Physiological SocietyÂ?s 2007 Frontiers in Physiology Program. For more information on this program, please visit www.frontiersinphys.org.

Dawn DeMayo (Montclair High School)

2007-08-01

81

Hfq stimulates the activity of the CCA-adding enzyme  

PubMed Central

Background The bacterial Sm-like protein Hfq is known as an important regulator involved in many reactions of RNA metabolism. A prominent function of Hfq is the stimulation of RNA polyadenylation catalyzed by E. coli poly(A) polymerase I (PAP). As a member of the nucleotidyltransferase superfamily, this enzyme shares a high sequence similarity with an other representative of this family, the tRNA nucleotidyltransferase that synthesizes the 3'-terminal sequence C-C-A to all tRNAs (CCA-adding enzyme). Therefore, it was assumed that Hfq might not only influence the poly(A) polymerase in its specific activity, but also other, similar enzymes like the CCA-adding enzyme. Results Based on the close evolutionary relation of these two nucleotidyltransferases, it was tested whether Hfq is a specific modulator acting exclusively on PAP or whether it also influences the activity of the CCA-adding enzyme. The obtained data indicate that the reaction catalyzed by this enzyme is substantially accelerated in the presence of Hfq. Furthermore, Hfq binds specifically to tRNA transcripts, which seems to be the prerequisite for the observed effect on CCA-addition. Conclusion The increase of the CCA-addition in the presence of Hfq suggests that this protein acts as a stimulating factor not only for PAP, but also for the CCA-adding enzyme. In both cases, Hfq interacts with RNA substrates, while a direct binding to the corresponding enzymes was not demonstrated up to now (although experimental data indicate a possible interaction of PAP and Hfq). So far, the basic principle of these stimulatory effects is not clear yet. In case of the CCA-adding enzyme, however, the presented data indicate that the complex between Hfq and tRNA substrate might enhance the product release from the enzyme. PMID:17949481

Scheibe, Marion; Bonin, Sonja; Hajnsdorf, Eliane; Betat, Heike; Mörl, Mario

2007-01-01

82

Enzyme immunoassay for methamphetamine.  

PubMed

A competitive enzyme immunoassay for methamphetamine with alkaline phosphatase labeled methamphetamine, Sepharose-antibody and p-nitrophenylphosphate as substrate was developed. The anti-methamphetamine antisera produced in rabbits by immunization with N-(4-aminobutyl) methamphetamine-BSA conjugate were specific for methamphetamine and showed low cross-reactivities with p-OH methamphetamine and amphetamine (metabolites of methamphetamine). The range of methamphetamine measurable by the enzyme immunoassay was 1 to 300 ng/tube. According to the assay, methamphetamine could be detected from urine and extract of hair. PMID:6343585

Aoki, K; Kuroiwa, Y

1983-01-01

83

STUDIES ON ENZYME ACTION  

PubMed Central

The ester-hydrolyzing or lipase actions of extracts and whole solids of trout eggs and whole trout of different ages were tested on ten simple esters by the method described in previous papers. Differences in solubility of the enzyme materials of the eggs were found. The "pictures" of the relative enzyme actions changed from a type found with immature eggs to a type which became constant for the fish after they had eaten for 2 weeks. After this, the type did not change up to the age of 4 to 5 years (the oldest trout studied). The absolute ester-hydrolyzing actions of the materials were also presented and discussed. PMID:19872363

Falk, K. George; Noyes, Helen Miller; Lorberblatt, I.

1927-01-01

84

Restriction Enzyme Analysis  

NSDL National Science Digital Library

Restriction mapping is a cornerstone of modern-day biotechnology. During this three-day exercise, students will digest samples of DNA with three different restriction enzymes. The DNA samples will be electrophoresed and the resulting fragments photographed under and ultraviolet transilluminator. Attached readings and activities will help explain the process of restriction enzyme analysis and how it is used in the DNA fingerprinting procedure. This 17-page pdf contains teacher information for presenting the activity, the complete procedure of the laboratory, and two student activities.

85

Monitoring enzyme kinetic behavior of enzyme-quantum dot bioconjugates  

NASA Astrophysics Data System (ADS)

Luminescent semiconductor nanocrystals or quantum dots (QDs) hold tremendous promise for in vivo biosensing, cellular imaging, theranostics, and smart molecular sensing probes due to their small size and favorable photonic properties such as resistance to photobleaching, size-tunable PL, and large effective Stokes shifts. Herein, we demonstrate how QD-based bioconjugates can be used to enhance enzyme kinetics. Enzyme-substrate kinetics are analyzed for solutions containing both alkaline phosphatase enzymes and QDs with enzyme-to- QD molar ratios of 2, 12, and 24 as well as for a solution containing the same concentration of enzymes but without QDs. The enzyme kinetic paramters Vmax, KM, and Kcat/KM are extracted from the enzyme progress curves via the Lineweaver-Burk plot. Results demonstrate an approximate increase in enzyme efficiency of 5 - 8% for enzymes immobilized on the QD versus free in solution without QD immobilization.

Claussen, Jonathan C.; Walper, Scott A.; Susumu, Kimihiro; Ancona, Mario G.; Medintz, Igor L.

2014-05-01

86

DNA photoreactivating enzyme from human tissues.  

PubMed

Photoreactivating enzyme activity has been quantitated in human fetal skin, kidney, lung, liver, brain and intestine, and in neonatal human foreskin. In all the tissues examined there were at least two activities: one nominally greater than 10,000 Da, and one nominally less than 10,000 Da. Both can photolyze pyrimidine dimers in DNA using only light of wavelengths greater than 320 nm, thus excluding tryptophan-mediated dimer splitting as an important mechanism for these activities. The activities are inactivated by digestion with trypsin or pronase, and decreased partially or totally by heating to 65 degrees C. The activities from all six tissues, as well as that from neonatal foreskin, act catalytically in dimer photolysis. The properties of macromolecular size, heat lability, protease sensitivity and catalytic pyrimidine dimer photolysis by a non-tryptophan-mediated mechanism correspond to those of a true photoreactivating enzyme. PMID:2509660

Ogut, S E; D'Ambrosio, S M; Samuel, M; Sutherland, B M

1989-10-01

87

Toying with Enzyme Catalysis.  

ERIC Educational Resources Information Center

Describes a set of manipulatives that are used to establish a secure understanding of the concepts related to the environmental factors that affect the activities of enzymes. Includes a description of the model components and procedures for construction of the model. (DDR)

Richards, Debbie

1998-01-01

88

The mononuclear molybdenum enzymes  

Microsoft Academic Search

Molybdenum is widely available to biological systems due to the solubility of its high-valent oxides in water and is found in two basic forms: as an integral component of the multinuclear M center of nitrogenases and as the mononuclear active sites of a much more diverse group of enzymes that in general function catalytically to transfer an oxygen atom either

Russ Hille

1996-01-01

89

The Enzyme Function Initiative†  

PubMed Central

The Enzyme Function Initiative (EFI) was recently established to address the challenge of assigning reliable functions to enzymes discovered in bacterial genome projects; in this Current Topic we review the structure and operations of the EFI. The EFI includes the Superfamily/Genome, Protein, Structure, Computation, and Data/Dissemination Cores that provide the infrastructure for reliably predicting the in vitro functions of unknown enzymes. The initial targets for functional assignment are selected from five functionally diverse superfamilies (amidohydrolase, enolase, glutathione transferase, haloalkanoic acid dehalogenase, and isoprenoid synthase), with five superfamily-specific Bridging Projects experimentally testing the predicted in vitro enzymatic activities. The EFI also includes the Microbiology Core that evaluates the in vivo context of in vitro enzymatic functions and confirms the functional predictions of the EFI. The deliverables of the EFI to the scientific community include: 1) development of a large-scale, multidisciplinary sequence/structure-based strategy for functional assignment of unknown enzymes discovered in genome projects (target selection, protein production, structure determination, computation, experimental enzymology, microbiology, and structure-based annotation); 2) dissemination of the strategy to the community via publications, collaborations, workshops, and symposia; 3) computational and bioinformatic tools for using the strategy; 4) provision of experimental protocols and/or reagents for enzyme production and characterization; and 5) dissemination of data via the EFI’s website, enzymefunction.org. The realization of multidisciplinary strategies for functional assignment will begin to define the full metabolic diversity that exists in nature and will impact basic biochemical and evolutionary understanding, as well as a wide range of applications of central importance to industrial, medicinal and pharmaceutical efforts. PMID:21999478

Gerlt, John A.; Allen, Karen N.; Almo, Steven C.; Armstrong, Richard N.; Babbitt, Patricia C.; Cronan, John E.; Dunaway-Mariano, Debra; Imker, Heidi J.; Jacobson, Matthew P.; Minor, Wladek; Poulter, C. Dale; Raushel, Frank M.; Sali, Andrej; Shoichet, Brian K.; Sweedler, Jonathan V.

2011-01-01

90

Enzyme linked immunoassay with stabilized polymer saccharide enzyme conjugates  

DOEpatents

An improvement in enzyme linked immunoassays is disclosed wherein the enzyme is in the form of a water soluble polymer saccharide conjugate which is stable in hostile environments. The conjugate comprises the enzyme which is linked to the polymer at multiple points through saccharide linker groups. 19 figs.

Callstrom, M.R.; Bednarski, M.D.; Gruber, P.R.

1997-11-25

91

Enzyme Molar Fractions: A Powerful Tool for Understanding Enzyme Kinetics.  

ERIC Educational Resources Information Center

Deduces the relationship between reduced velocity and molar fractions for productive enzyme complexes; obtains the mathematical expression of molar fractions for an enzyme with two specific binding sites per molecule; and proposes a useful plot to follow the dependence of enzyme molar fractions with the concentration of one of its ligands. (JN)

Serra, Juan L.; And Others

1986-01-01

92

Enzyme linked immunoassay with stabilized polymer saccharide enzyme conjugates  

DOEpatents

An improvement in enzyme linked immunoassays is disclosed wherein the enzyme is in the form of a water soluble polymer saccharide conjugate which is stable in hostile environments. The conjugate comprises the enzyme which is linked to the polymer at multiple points through saccharide linker groups.

Callstrom, Matthew R. (Columbus, OH); Bednarski, Mark D. (Berkeley, CA); Gruber, Patrick R. (St. Paul, MN)

1997-01-01

93

Red cell enzymes.  

PubMed

Mutations leading to red cell enzyme deficiencies can be associated with diverse phenotypes that range from hemolytic anemia, methemoglobinemia, polycythemia, and neurological and developmental abnormalities. While most of these mutations occur sporadically, some such as common glucose-6-phosphate dehydrogenase (G6PD) mutants are endemic and rarely cause disease. Common G6PD mutants likely reached their prevalence because they provide some protection against severe malarial complications. In this review G6PD, pyruvate kinase, 5' nucleotidase, and cytochrome b5 reductase deficiencies will be discussed in greater detail. Limitations of commonly used screening tests for detection of these disorders will also be emphasized, as well as emerging knowledge about non-enzymatic function of the glycolytic enzymes. PMID:16304354

Prchal, Josef T; Gregg, Xylina T

2005-01-01

94

Act II of the Sunshine Act.  

PubMed

To coincide with the introduction in the United States of the Sunshine Act, Genevieve Pham-Kanter discusses what we need to look for to fight hidden bias and deliberate or unconscious corruption. Please see later in the article for the Editors' Summary. PMID:25369363

Pham-Kanter, Genevieve

2014-11-01

95

Pyridoxal Phosphate as a Tag to Identify Enzymes Within the “PLP-ome”  

E-print Network

The main objective of this research was to develop a protocol in which pyridoxal phosphate (PLP) would act as a tag to identify PLP-dependent enzymes from complex mixtures or cell lysates. Following the purification of a PLP-dependent enzyme (Cys...

Messer, Kayla J.

2012-07-16

96

Molecular Control of Nitrate Reductase and Other Enzymes Involved in Nitrate Assimilation  

Microsoft Academic Search

Nitrate acts as both a nutrient and a signal in plants. Nitrate induces gene expression of enzymes for its metabolism into amino acids but also has other effects on plant metabolism and development. Familiar nitrate-induced enzymes are nitrate and nitrite reductases, nitrate transporters, glutamine synthetase, glutamate synthase, ferredoxin and ferredoxin NADP+ reductase. Microarray analysis of nitrate-stimulated gene expression has identified

Wilbur H. Campbell

97

Nuclear Shield: A Multi-Enzyme Task-Force for Nucleus Protection  

Microsoft Academic Search

BackgroundIn eukaryotic cells the nuclear envelope isolates and protects DNA from molecules that could damage its structure or interfere with its processing. Moreover, selected protection enzymes and vitamins act as efficient guardians against toxic compounds both in the nucleoplasm and in the cytosol. The observation that a cytosolic detoxifying and antioxidant enzyme i.e. glutathione transferase is accumulated in the perinuclear

Raffaele Fabrini; Alessio Bocedi; Valentina Pallottini; Lorena Canuti; Michele de Canio; Andrea Urbani; Valeria Marzano; Tommaso Cornetta; Pasquale Stano; Anna Giovanetti; Lorenzo Stella; Antonella Canini; Giorgio Federici; Giorgio Ricci; Sue Cotterill

2010-01-01

98

Contact Dermatitis in Home Helps Following the Use of Enzyme Detergents  

PubMed Central

Twelve women in the home help service in Nottingham developed dermatitis after using enzyme detergents. A survey based on a questionary showed an incidence of 5% among those using them. The enzyme appears to act as a primary irritant. PMID:5435187

Ducksbury, Christina F. J.; Dave, V. K.

1970-01-01

99

Quorum quenching enzymes.  

PubMed

Bacteria use cell-to-cell communication systems based on chemical signal molecules to coordinate their behavior within the population. These quorum sensing systems are potential targets for antivirulence therapies, because many bacterial pathogens control the expression of virulence factors via quorum sensing networks. Since biofilm maturation is also usually influenced by quorum sensing, quenching these systems may contribute to combat biofouling. One possibility to interfere with quorum sensing is signal inactivation by enzymatic degradation or modification. Such quorum quenching enzymes are wide-spread in the bacterial world and have also been found in eukaryotes. Lactonases and acylases that hydrolyze N-acyl homoserine lactone (AHL) signaling molecules have been investigated most intensively, however, different oxidoreductases active toward AHLs or 2-alkyl-4(1H)-quinolone signals as well as other signal-converting enzymes have been described. Several approaches have been assessed which aim at alleviating virulence, or biofilm formation, by reducing the signal concentration in the bacterial environment. These involve the application or stimulation of signal-degrading bacteria as biocontrol agents in the protection of crop plants against soft-rot disease, the use of signal-degrading bacteria as probiotics in aquaculture, and the immobilization or entrapment of quorum quenching enzymes or bacteria to control biofouling in membrane bioreactors. While most approaches to use quorum quenching as antivirulence strategy are still in the research phase, the growing number of organisms and enzymes known to interfere with quorum sensing opens up new perspectives for the development of innovative antibacterial strategies. PMID:25220028

Fetzner, Susanne

2015-05-10

100

Purification and characterization of a tuliposide-converting enzyme from bulbs of Tulipa gesneriana.  

PubMed

An enzyme that catalyzes the stoichiometric conversion of 6-tuliposide into tulipalin was purified and characterized from bulbs of Tulipa gesneriana. The enzyme appeared to be a dimer, the relative molecular mass (Mr) of each subunit being 34,900; it had maximum activity and stability at neutral pH and moderate temperature. The enzyme preferentially acted on such glucose esters as 6-tuliposides, and to a lesser extent on p-nitrophenylacetate. PMID:19661715

Kato, Yasuo; Shoji, Kazuaki; Ubukata, Makoto; Shigetomi, Kengo; Sato, Yukio; Nakajima, Noriyuki; Ogita, Shinjiro

2009-08-01

101

Medicinal Chemistry and Enzyme Kinetics  

E-print Network

Medicinal Chemistry and Enzyme Kinetics Elizabeth Amin and C. R. Wagner, Medicinal Chemistry Jiali Stankovich, Jiali Gao, and Donald G. Truhlar, University of Minnesota February 2007 Enzyme Kinetics Kinetic isotope effects Variational transition state theory Multidimensional tunneling Ensemble averaging

Truhlar, Donald G

102

Treating Wastewater With Immobilized Enzymes  

NASA Technical Reports Server (NTRS)

Experiments show enzymes are immobilized on supporting materials to make biocatalyst beds for treatment of wastewater. With suitable combination of enzymes, concentrations of various inorganic and organic contaminants, including ammonia and urea, reduced significantly.

Jolly, Clifford D.

1991-01-01

103

Original article Lipogenic enzyme activities  

E-print Network

Original article Lipogenic enzyme activities in subcutaneous adipose tissue and skeletal muscle, lipogenic enzyme activities and expression of GLUT4 mRNA were determined in subcutaneous adipose tissue. In adipose tissue, acetyl-CoA-carboxylase (CBX), fatty acid synthase (FAS), malic enzyme (ME), glucose-6

Paris-Sud XI, Université de

104

Silica-Immobilized Enzyme Reactors  

Microsoft Academic Search

Recent studies have demonstrated the applicability and versatility of immobilized enzyme reactors (IMERs) for chemical and biochemical synthesis and analysis. The majority of IMER systems rely on enzymes immobilized to packed matrices within flow-through devices. This review focuses primarily on the use of silica as a support for enzyme immobilization and specific applications of the resulting silica-based IMERs. A number

Heather R. Luckarift

2008-01-01

105

The Catalytic Function of Enzymes.  

ERIC Educational Resources Information Center

Discusses: structure of the enzyme molecule; active site; reaction mechanism; transition state; factors affecting enzyme reaction rates, concentration of enzyme; concentration of substrate; product concentration; temperature effects and pH effects; factors causing a lowering of activation energy; proximity and orientation effects; substrate strain…

Splittgerber, Allan G.

1985-01-01

106

Public Health Act, 1961   

E-print Network

An Act to amend the provisions of the Public Health Act, 1936, relating to building byelaws, to make such amendments of the law relating to public health and the functions of county councils and other local authorities as are commonly made in local...

Her Majesty's Stationary Office

1961-01-01

107

Direct in situ observation of synergism between cellulolytic enzymes during the biodegradation of crystalline cellulose fibers.  

PubMed

High-resolution atomic force microscopy (AFM) was used to image the real-time in situ degradation of crystalline by three types of T. reesei cellulolytic enzymes-TrCel6A, TrCel7A, and TrCel7B-and their mixtures. TrCel6A and TrCel7A are exo-acting cellobiohydrolases processing cellulose fibers from the nonreducing and reducing ends, respectively. TrCel7B is an endoglucanase that hydrolyzes amorphous cellulose within fibers. When acting alone on native cellulose fibers, each of the three enzymes is incapable of significant degradation. However, mixtures of two enzymes exhibited synergistic effects. The degradation effects of this synergism depended on the order in which the enzymes were added. Faster hydrolysis rates were observed when TrCel7A (exo) was added to fibers pretreated first with TrCel7B (endo) than when adding the enzymes in the opposite order. Endo-acting TrCel7B removed amorphous cellulose, softened and swelled the fibers, and exposed single microfibrils, facilitating the attack by the exo-acting enzymes. AFM images revealed that exo-acting enzymes processed the TrCel7B-pretreated fibers preferentially from one specific end (reducing or nonreducing). The most efficient (almost 100%) hydrolysis was observed with the mixture of the three enzymes. In this mixture, TrCel7B softened the fiber and TrCel6A and TrCel7A were directly observed to process it from the two opposing ends. This study provides high-resolution direct visualization of the nature of the synergistic relation between T. reesei exo- and endo-acting enzymes digesting native crystalline cellulose. PMID:24195649

Wang, Jingpeng; Quirk, Amanda; Lipkowski, Jacek; Dutcher, John R; Clarke, Anthony J

2013-12-01

108

Microbial Enzymes with Special Characteristics for Biotechnological Applications  

PubMed Central

This article overviews the enzymes produced by microorganisms, which have been extensively studied worldwide for their isolation, purification and characterization of their specific properties. Researchers have isolated specific microorganisms from extreme sources under extreme culture conditions, with the objective that such isolated microbes would possess the capability to bio-synthesize special enzymes. Various Bio-industries require enzymes possessing special characteristics for their applications in processing of substrates and raw materials. The microbial enzymes act as bio-catalysts to perform reactions in bio-processes in an economical and environmentally-friendly way as opposed to the use of chemical catalysts. The special characteristics of enzymes are exploited for their commercial interest and industrial applications, which include: thermotolerance, thermophilic nature, tolerance to a varied range of pH, stability of enzyme activity over a range of temperature and pH, and other harsh reaction conditions. Such enzymes have proven their utility in bio-industries such as food, leather, textiles, animal feed, and in bio-conversions and bio-remediations. PMID:24970183

Nigam, Poonam Singh

2013-01-01

109

A sensitive enzyme electrode for phenol monitoring  

SciTech Connect

Tyrosinase (EC.1.14.18.1) was immobilized onto graphite electrodes, which had been modified with tetracyanoquinodimethane (TCNQ). The response time, 12 or 35 s, was dependent on the enzyme immobilization technique used. The electrodes showed a linear calibration function up to 25 or 65 {mu}M phenol, and a sensitivity of 0.36 or 2.2 A/M was achieved which was also dependent on the enzyme immobilization technique used. The detection limit for phenol was 0.23 {mu}M. The electrodes acted from potentials of {minus}200 to +180 mV (vs. a saturated Ag/AgCl electrode). The electrode signal was independent of pH within the pH range 4.5-6.0. The enzyme electrode responded to phenol (100%), p-cresol (93%) and catechol (330%), but not to o-cresol and L-tyrosine. The electrodes showed a stability for more than one week. The electrodes can be utilized for the sensitive assay of phenol in water.

Kulys, J.; Schmid, R.D. (GBF-Gesellschaft fuer Biotechnologische Forschung mbH, Braunschweig (West Germany))

1990-01-01

110

Protein Crystal Malic Enzyme  

NASA Technical Reports Server (NTRS)

Malic Enzyme is a target protein for drug design because it is a key protein in the life cycle of intestinal parasites. After 2 years of effort on Earth, investigators were unable to produce any crystals that were of high enough quality and for this reason the structure of this important protein could not be determined. Crystals obtained from one STS-50 were of superior quality allowing the structure to be determined. This is just one example why access to space is so vital for these studies. Principal Investigator is Larry DeLucas.

1992-01-01

111

Industrial use of immobilized enzymes.  

PubMed

Although many methods for enzyme immobilization have been described in patents and publications, relatively few processes employing immobilized enzymes have been successfully commercialized. The cost of most industrial enzymes is often only a minor component in overall process economics, and in these instances, the additional costs associated with enzyme immobilization are often not justified. More commonly the benefit realized from enzyme immobilization relates to the process advantages that an immobilized catalyst offers, for example, enabling continuous production, improved stability and the absence of the biocatalyst in the product stream. The development and attributes of several established and emerging industrial applications for immobilized enzymes, including high-fructose corn syrup production, pectin hydrolysis, debittering of fruit juices, interesterification of food fats and oils, biodiesel production, and carbon dioxide capture are reviewed herein, highlighting factors that define the advantages of enzyme immobilization. PMID:23436023

DiCosimo, Robert; McAuliffe, Joseph; Poulose, Ayrookaran J; Bohlmann, Gregory

2013-08-01

112

The ACT domain family.  

PubMed

A novel ligand-binding domain, named the 'ACT domain', was recently identified by a PSI-BLAST search. The archetypical ACT domain is the C-terminal regulatory domain of 3-phosphoglycerate dehydrogenase (3PGDH), which folds with a ferredoxin-like betaalphabetabetaalphabeta topology. A pair of ACT domains form an eight-stranded antiparallel sheet with two molecules of the allosteric inhibitor serine bound in the interface. The ACT domain is found in a variety of contexts and is proposed to be a conserved regulatory ligand binding fold. Rat phenylalanine hydroxylase has a regulatory domain with a similar fold, but different ligand-binding mode. Putative ACT domains in some proteins of unknown structure (e.g. acetohydroxyacid synthase regulatory subunits) may also fold like the 3PGDH regulatory domain. The regulatory domain of threonine deaminase, although not a member of the ACT sequence family, is similar in structure to the paired 3PGDH regulatory domains. Repeats of ACT-like domains can create nonequivalent ligand-binding sites with the potential for complex regulatory patterns. The structures and mechanisms of such systems have only begun to be examined. PMID:11751050

Chipman, D M; Shaanan, B

2001-12-01

113

RNA EDITING BY ADENOSINE DEAMINASES THAT ACT ON RNA  

E-print Network

RNA EDITING BY ADENOSINE DEAMINASES THAT ACT ON RNA Brenda L. Bass Department of Biochemistry-mail: bbass@howard.genetics.utah.edu Key Words double-stranded RNA, inosine, deaminase, neurotransmission f An Overview of RNA Editing by Adenosine Deamination . . . . . . . . . . . . . . 818 THE ENZYME FAMILY

Bass, Brenda L.

114

PHYSIOLOGY: Sister Act  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Particular fibroblast growth factors function as metabolic hormones and act through a certain signaling cascade design to control specific states of homeostasis.

David D. Moore (Baylor College of Medicine; Department of Molecular and Cellular Biology)

2007-06-08

115

Disabilities Act in Action.  

ERIC Educational Resources Information Center

Eight true or false questions explore implications of the Americans with Disabilities Act of 1990. Topics include AIDS, drug abuse, undue hardship, reasonable accommodation, and company size affected by the law. (SK)

Daynes, Kristine S.

1990-01-01

116

Pool & Spa Safety Act  

MedlinePLUS

... Stories Pool Safely Home Consumer Product Safety Commission, CPSC CPSC Home The Pool & Spa Safety Act Contact Information About PoolSafely.gov and CPSC The U.S. Consumer Product Safety Commission (CPSC) is ...

117

Assertive Community Treatment (ACT)  

MedlinePLUS

... Treatment FACT SHEET NAMI • The National Alliance on Mental Illness • 1 (800) 950-NAMI • www.nami.org 3803 ... be very effective in the treatment of severe mental illness. ACT is aimed at providing comprehensive multidisciplinary care ...

118

ACTS mobile SATCOM experiments  

NASA Technical Reports Server (NTRS)

Over the last decade, the demand for reliable mobile satellite communications (satcom) for voice, data, and video applications has increased dramatically. As consumer demand grows, the current spectrum allocation at L-band could become saturated. For this reason, NASA and the Jet Propulsion Laboratory are developing the Advanced Communications Technology Satellites (ACTS) mobile terminal (AMT) and are evaluating the feasibility of K/Ka-band (20/30 GHz) mobile satcom to meet these growing needs. U.S. industry and government, acting as co-partners, will evaluate K/Ka-band mobile satcom and develop new technologies by conducting a series of applications-oriented experiments. The ACTS and the AMT testbed will be used to conduct these mobile satcom experiments. The goals of the ACTS Mobile Experiments Program and the individual experiment configurations and objectives are further presented.

Abbe, Brian S.; Frye, Robert E.; Jedrey, Thomas C.

1993-01-01

119

Public Health Service Act  

Cancer.gov

The Public Health Service was established by act of July 16, 1798 (ch. 77, 1 Stat. 605), authorizing marine hospitals for the care of American merchant seamen. Subsequent legislation has vastly broadened the scope of its activities.

120

7 CFR 58.436 - Rennet, pepsin, other milk clotting enzymes and flavor enzymes.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436 Section 58.436 Agriculture ...58.436 Rennet, pepsin, other milk clotting enzymes and flavor enzymes. Enzyme preparations used...

2011-01-01

121

7 CFR 58.436 - Rennet, pepsin, other milk clotting enzymes and flavor enzymes.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436 Section 58.436 Agriculture ...58.436 Rennet, pepsin, other milk clotting enzymes and flavor enzymes. Enzyme preparations used...

2010-01-01

122

7 CFR 58.436 - Rennet, pepsin, other milk clotting enzymes and flavor enzymes.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436 Section 58.436 Agriculture ...58.436 Rennet, pepsin, other milk clotting enzymes and flavor enzymes. Enzyme preparations used...

2013-01-01

123

7 CFR 58.436 - Rennet, pepsin, other milk clotting enzymes and flavor enzymes.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436 Section 58.436 Agriculture ...58.436 Rennet, pepsin, other milk clotting enzymes and flavor enzymes. Enzyme preparations used...

2012-01-01

124

7 CFR 58.436 - Rennet, pepsin, other milk clotting enzymes and flavor enzymes.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436 Section 58.436 Agriculture ...58.436 Rennet, pepsin, other milk clotting enzymes and flavor enzymes. Enzyme preparations used...

2014-01-01

125

Stabilization of the cellulase enzyme complex as enzyme nanoparticle.  

PubMed

The native Celluclast BG cellulase enzyme complex consists of different enzymes which can also degrade great substrate molecules as native celluloses. This enzyme complex has been covered by a very thin, a few nanometers thick, polymer layer, in order to improve its stability. It has been proved that the polymer layer around the enzyme molecules does not hinder the digestion as great substrates as crystalline cellulose polymer. The stability of the prepared enzyme nanoparticles (PE) could significantly be increased comparing to that of the native one what was proved by results of the total cellulose activity measured. The pretreated enzyme complex holds its activity often a few magnitudes of orders longer in time than that of the native enzyme complex (enzyme without pretreatment). It retains its activity at least ten times longer than that of the native one, at a temperature range between 20 and 37 °C. The pretreated enzyme complex can have about 50 % of its original activity during 12 h of incubation at even 80 °C, while the native cellulase one totally lost it during 6 h incubation time. The activity of PE has not been significantly reduced even at extreme pH values, namely in the pH range of 1.5 to 12. PMID:22956300

Hegedüs, Imre; Hancsók, Jen?; Nagy, Endre

2012-11-01

126

Enzyme molecules in solitary confinement.  

PubMed

Large arrays of homogeneous microwells each defining a femtoliter volume are a versatile platform for monitoring the substrate turnover of many individual enzyme molecules in parallel. The high degree of parallelization enables the analysis of a statistically representative enzyme population. Enclosing individual enzyme molecules in microwells does not require any surface immobilization step and enables the kinetic investigation of enzymes free in solution. This review describes various microwell array formats and explores their applications for the detection and investigation of single enzyme molecules. The development of new fabrication techniques and sensitive detection methods drives the field of single molecule enzymology. Here, we introduce recent progress in single enzyme molecule analysis in microwell arrays and discuss the challenges and opportunities. PMID:25221867

Liebherr, Raphaela B; Gorris, Hans H

2014-01-01

127

de novo computational enzyme design.  

PubMed

Recent advances in systems and synthetic biology as well as metabolic engineering are poised to transform industrial biotechnology by allowing us to design cell factories for the sustainable production of valuable fuels and chemicals. To deliver on their promises, such cell factories, as much as their brick-and-mortar counterparts, will require appropriate catalysts, especially for classes of reactions that are not known to be catalyzed by enzymes in natural organisms. A recently developed methodology, de novo computational enzyme design can be used to create enzymes catalyzing novel reactions. Here we review the different classes of chemical reactions for which active protein catalysts have been designed as well as the results of detailed biochemical and structural characterization studies. We also discuss how combining de novo computational enzyme design with more traditional protein engineering techniques can alleviate the shortcomings of state-of-the-art computational design techniques and create novel enzymes with catalytic proficiencies on par with natural enzymes. PMID:24794534

Zanghellini, Alexandre

2014-10-01

128

Enzymes Help Us Digest Food  

NSDL National Science Digital Library

Experiments with the enzyme lactase and discussion questions help students to learn about enzyme function, enzyme specificity, and the molecular basis of lactose intolerance. Students also learn about the scientific method by interpreting evidence to test hypotheses and designing the second and third experiments to answer specific scientific questions about lactase. (An alternative version of the Student Handout gives specific instructions for all three of the experiments.)

Jennifer Doherty

129

Immobilized Cell and Enzyme Technology  

NASA Astrophysics Data System (ADS)

The development of immobilized enzyme and cell technology is summarized. Industrial processes for sucrose inversion, penicillin deacylation and glucose isomerization using immobilized enzymes are described. An alternative process for glucose isomerization using immobilized cells, and some other industrial applications of immobilized cells are indicated. Recent developments in immobilized enzyme and cell technology are assessed and the relative merits of the different biochemical catalyst forms are considered.

Dunnill, P.

1980-08-01

130

Thermostable Enzymes in Lignocellulose Hydrolysis  

Microsoft Academic Search

Thermostable enzymes offer potential benefits in the hydrolysis of lignocellulosic substrates; higher\\u000a specific activity decreasing the amount of enzymes, enhanced stability allowing improved hydrolysis performance\\u000a and increased flexibility with respect to process configurations, all leading to improvement of the overall\\u000a economy of the process. New thermostable cellulase mixtures were composed of cloned fungal enzymes for\\u000a hydrolysis experiments. Three thermostable cellulases,

Liisa Viikari; Marika Alapuranen; Terhi Puranen; Jari Vehmaanperä; Matti Siika-aho

131

Self-powered enzyme micropumps Samudra Sengupta1, Debabrata Patra1, Isamar Ortiz-Rivera1, Arjun Agrawal1, Sergey Shklyaev2,  

E-print Network

by the presence of specific analytes, which enables the design of enzyme-based devices that act both as sensor and pump. Finally, we show proof-of-concept enzyme-powered devices that autonomously deliver small a novel enzyme-based platform that combines sensing and microfluidic pumping into a single self

132

Integrated microdroplet-based system for enzyme synthesis and sampling  

NASA Astrophysics Data System (ADS)

Microdroplet-based microfluidic devices are emerging as powerful tools for a wide range of biochemical screenings and analyses. Monodispersed aqueous microdroplets from picoliters to nanoliters in volume are generated inside microfluidic channels within an immiscible oil phase. This results in the formation of emulsions which can contain various reagents for chemical reactions and can be considered as discrete bioreactors. In this paper an integrated microfluidic platform for the synthesis, screening and sorting of libraries of an organophosphate degrading enzyme is presented. The variants of the selected enzyme are synthesized from a DNA source using in-vitro transcription and translation method. The synthesis occurs inside water-in-oil emulsion droplets, acting as bioreactors. Through a fluorescence based detection system, only the most efficient enzymes are selected. All the necessary steps from the enzyme synthesis to selection of the best genes (producing the highest enzyme activity) are thus integrated inside a single and unique device. In the second part of the paper, an innovative design of the microfluidic platform is presented, integrating an electronic prototyping board for ensuring the communication between the various components of the platform (camera, syringe pumps and high voltage power supply), resulting in a future handheld, user-friendly, fully automated device for enzyme synthesis, screening and selection. An overview on the capabilities as well as future perspectives of this new microfluidic platform is provided.

Lapierre, Florian; Best, Michel; Stewart, Robert; Oakeshott, John; Peat, Thomas; Zhu, Yonggang

2013-12-01

133

Enzyme actuated bioresponsive hydrogels  

NASA Astrophysics Data System (ADS)

Bioresponsive hydrogels are emerging with technological significance in targeted drug delivery, biosensors and regenerative medicine. Conferred with the ability to respond to specific biologically derived stimuli, the design challenge is in effectively linking the conferred biospecificity with an engineered response tailored to the needs of a particular application. Moreover, the fundamental phenomena governing the response must support an appropriate dynamic range and limit of detection. The design of these systems is inherently complicated due to the high interdependency of the governing phenomena that guide the sensing, transduction, and the actuation response of hydrogels. To investigate the dynamics of these materials, model systems may be used which seek to interrogate the system dynamics by uni-variable experimentation and limit confounding phenomena such as: polymer-solute interactions, polymer swelling dynamics and biomolecular reaction-diffusion concerns. To this end, a model system, alpha-chymotrypsin (Cht) (a protease) and a cleavable peptide-chromogen (pro-drug) covalently incorporated into a hydrogel, was investigated to understand the mechanisms of covalent loading and release by enzymatic cleavage in bio-responsive delivery systems. Using EDC and Sulfo-NHS, terminal carboxyl groups of N-succinyl-Ala-Ala-Pro-Phe p-nitroanilide, a cleavable chromogen, were conjugated to primary amines of a hydrated poly(HEMA)-based hydrogel. Hydrogel discs were incubated in buffered Cht causing enzyme-mediated cleavage of the peptide and concomitant release of the chromophore for monitoring. To investigate substrate loading and the effects of hydrogel morphology on the system, the concentration of the amino groups (5, 10, 20, and 30 mol%) and the cross-linked density (1, 5, 7, 9 and 12 mol%) were independently varied. Loading-Release Efficiency of the chromogen was shown to exhibit a positive relation to increasing amino groups (AEMA). The release rates demonstrated a negative relation to increasing cross-linked density attributed to decreasing void fractions and increasing tortuosities. The diffusion coefficient of Cht, D0, Cht, was determined to be 6.9 +/- 0.5 x 10-7 cm2 s -1, and the range of Deff of Cht for 1 to 12 mol% TEGDA was determined to 6.9 x10-8 to 0.1 x 10 -8cm2 s-1. We show how these parameters may be optimized and used to achieve programmed release rates in engineered bio-responsive systems. The field of bioresponsive hydrogels is continuing to expand as the need for such materials persists. Future work will enable more control over the loading and release of therapeutic and diagnostic moieties. Continued research regarding in enzymatically actuated hydrogels will involve pre-polymerization loading methodologies; in silico diffusion-reaction multiphysics modeling; enzyme actuated degradation of the polymer; and substation of various mediating enzyme, cleavable peptides, and release molecules.

Wilson, Andrew Nolan

134

Freedom of Information Act  

NSDL National Science Digital Library

The Freedom of Information Act (FOIA) website, part of the National Archives and Record Administration (NARA) has been making it easy for journalists, scholars, activists, or any interested party with the statutory right, to get U.S. government information in executive branch agency records. Visitors interested in getting some information, should first read the "FOIA Reference Guide", which can be accessed via the link in the menu on the top left side of any page. The "FOIA Reference Guide" provides the proper way to make a FOIA request. Users can learn more about "Other FOIA Resources" via the link in the menu on the left side, in the bottom corner. There are a couple of links to other government agencies' information on FOIA, as well as a link to a pamphlet called "Your Right To Federal Records" and a link to "A Citizen's Guide to Using the Freedom of Information Act and Privacy Act of 1974 to Request Government Records".

135

Fair Labor Standards Act (FLSA) Fair Labor Standards Act (FLSA)  

E-print Network

Fair Labor Standards Act (FLSA) June 2014 #12;Fair Labor Standards Act (FLSA) 1 The purpose. The Fair Labor Standards Act was passed in 1938 Established a minimum wage Delaware $7.75/hour Provided standards Equal Pay Workweek Overtime Pay Record Keeping Youth Employment #12;Fair Labor Standards Act 2

Firestone, Jeremy

136

Making the Rate: Enzyme Dynamics  

ERIC Educational Resources Information Center

An enzyme exercise to address the problem of students inability to visualize chemical reaction at the molecular level is described. This exercise is designed as a dry lab exercise but can be modified into a classroom activity then can be augmented by a wet lab procedure, thereby providing students with a practical exposure to enzyme function.

Ragsdale, Frances R.

2004-01-01

137

Enzyme technology and bioprocess engineering  

Microsoft Academic Search

The impact of directed evolution and site-specific mutagenesis on the industrial utility of enzymatic catalysis through the modification of enzyme structure and function is clearly an important area of research in bioprocess engineering. High-throughput screening for novel or improved enzyme activities, both by more efficiently exploring nature's diversity and by creating new diversity in the test tube, allows new bioprocesses

Sven Panke; Marcel G Wubbolts

2002-01-01

138

Restriction Enzymes and DNA Fingerprinting  

NSDL National Science Digital Library

The discovery of restriction enzymes and their applications in DNA analysis has proven to be essential for biologists and chemists. This lesson focuses on restriction enzymes and their applications to DNA analysis and DNA fingerprinting. Use this lesson and its associated activity in conjunction with biology lessons on DNA analysis and DNA replication.

National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs,

139

Enzyme Investigations for Introductory Courses  

NSDL National Science Digital Library

This resource is a detailed manual for instructing a laboratory exercise in cellular physiology and enzyme kinetic. For example, students will ascertain how various factors (temperature, pH, substrate and enzyme concentration) affect the rate of reaction. This exercise is suitable for introductory courses in cellular biology, physiology, or courses requiring a moderate understanding of biochemistry.

Ruthanne B. Pitkin (Shippensburg University; )

1992-01-01

140

Recent advances in enzyme assays  

Microsoft Academic Search

Enzyme assays for high-throughput screening and enzyme engineering, which are often based on derivatives of coumarin, nitrophenol, fluorescein, nitrobenzofurazane or rhodamine dyes, can be divided into two categories: those that depend on labelled substrates, and those that depend on sensing the reactions of unmodified substrates. Labelled substrates include, for example, fluorogenic and chromogenic substrates that generate a reporter molecule by

Jean-Philippe Goddard; Jean-Louis Reymond

2004-01-01

141

Enzyme Catalysis in Organic Synthesis  

Microsoft Academic Search

The present state of enzyme catalysis and the prospects for its introduction in organic synthesis are examined. The physicochemical approaches whereby the yield of the desired product can be increased under conditions favourable for biocatalysis (at the optimum of the catalytic activity and stability of the enzyme) are analysed. Together with classical equilibrium and kinetic preparative methods, the thermodynamic features

K. Martinek; A. N. Semenov

1981-01-01

142

Safety Regulations of Food Enzymes  

Microsoft Academic Search

Summary The majority of industrial enzymes available at present is used in food industry. Safe- ty regulations of food enzymes differ among countries, including fundamental aspects, whether a pre-market approval is needed and on the level of details, e.g. what particular information manufacturers have to provide in the course of safety evaluation. Occupa- tional safety concerns focus on allergenic properties

Armin Spök

143

An oxidative enzyme boosting the enzymatic conversion of recalcitrant polysaccharides.  

PubMed

Efficient enzymatic conversion of crystalline polysaccharides is crucial for an economically and environmentally sustainable bioeconomy but remains unfavorably inefficient. We describe an enzyme that acts on the surface of crystalline chitin, where it introduces chain breaks and generates oxidized chain ends, thus promoting further degradation by chitinases. This enzymatic activity was discovered and further characterized by using mass spectrometry and chromatographic separation methods to detect oxidized products generated in the absence or presence of H(2)(18)O or (18)O(2). There are strong indications that similar enzymes exist that work on cellulose. Our findings not only demonstrate the existence of a hitherto unknown enzyme activity but also provide new avenues toward more efficient enzymatic conversion of biomass. PMID:20929773

Vaaje-Kolstad, Gustav; Westereng, Bjřrge; Horn, Svein J; Liu, Zhanliang; Zhai, Hong; Sřrlie, Morten; Eijsink, Vincent G H

2010-10-01

144

Positron emitter labeled enzyme inhibitors  

SciTech Connect

This invention involves a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide inactivators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography.

Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.; Langstrom, B.

1990-04-03

145

Positron emitter labeled enzyme inhibitors  

DOEpatents

This invention involves a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide inactivators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography.

Fowler, Joanna S. (Bellport, NY); MacGregor, Robert R. (Sag Harbor, NY); Wolf, Alfred P. (Setauket, NY); Langstrom, Bengt (Upsala, SE)

1990-01-01

146

Positron emitter labeled enzyme inhibitors  

DOEpatents

This invention involved a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide in activators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography. 2 figs.

Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.

1987-05-22

147

The USA PATRIOT Act.  

ERIC Educational Resources Information Center

Explains the USA PATRIOT (Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism) Act, passed after the September 11 terrorist attacks, and its implications for libraries and patron records. Considers past dealings with the FBI; court orders; search warrants; wiretaps; and subpoenas. Includes:…

Minow, Mary; Coyle, Karen; Kaufman, Paula

2002-01-01

148

Improving America's Schools Act  

NASA Technical Reports Server (NTRS)

The Improving America's Schools ACT (IASA) emphasizes coherent systemic education reform, with Goals 2000 setting common standards for IASA and the recently authorized School-to-Work Program. IASA addresses the need to raise academic achievement, increase opportunities to learn, improve professional development, increase community involvement, utilize instructional applications of technology, and improve assessment, and allow more local flexibility in the use of funds.

Cradler, John; Bridgforth, Elizabeth

1995-01-01

149

An adenosine-to-inosine tRNA-editing enzyme that can perform C-to-U deamination of DNA  

E-print Network

for viability. Enzymes mediating tRNA adenosine deamination in bacteria and yeast contain cytidine deaminase-binding pocket: (i) the adenosine deaminases acting on RNAs (ADARs) and (ii) the polynucle- otide cytidineAn adenosine-to-inosine tRNA-editing enzyme that can perform C-to-U deamination of DNA Mary Anne T

Papavasiliou, F. Nina

150

Immobilization of enzymes masks their active site  

Microsoft Academic Search

We studied the effect of immobilizing cellulase to carboxycellulose sodium by radiation polymerization on the masking of the active site of the enzyme. Masking of the enzyme during the preparation of immobilized enzyme was assayed at tow temperature. The activity of immobilized enzyme was retained during repeated batch reactions, indicating that the enzyme was firmly trapped in the polymer matrix.

Minoru Kumakura; Isao Kaetsu

1984-01-01

151

MECHANISMS OF LYSOSOMAL ENZYME RELEASE FROM HUMAN LEUKOCYTES  

PubMed Central

In order to study mechanisms underlying selective enzyme release from human leukocytes during phagocytosis, the effects were studied of compounds which affect microtubule integrity or the accumulation of cyclic nucleotides. Human leukocytes selectively extrude lysosomal enzymes (?-glucuronidase) from viable cells during phagocytosis of zymosan or immune complexes, or upon encounter with immune complexes dispersed along a non-phagocytosable surface such as a millipore filter. In each circumstance, lysosomal enzyme release was reduced by previous treatment of cells with pharmacological doses of drugs which disrupt microtubules (e.g. 10-3–10-5 M colchicine) or with agents which affect accumulation of adenosine 3'5'-monophosphate (cAMP) (e.g. 10-3 M cyclic nucleotides and 2.8 x 10-4–2.8 x 10-6 M prostaglandin E (PGE) and A (PGA) compounds). Preincubation of cells with 5 µg/ml cytochalasin B resulted in complete inhibition of zymosan ingestion, but not of adherence of zymosan particles to plasma membranes or selective enzyme release. In this system, in which enzyme release was independent of particle uptake, preincubation of cells with colchicine, vinblastine, dibutyryl cAMP, or PGE1 also reduced extrusion of lysosomal enzymes. When cell suspensions were incubated with membrane-lytic crystals of monosodium urate (MSU), cytoplasmic as well as lysosomal enzymes were released with subsequent death of the cells. However, enzyme release followed phagocytosis of crystals (as measured by enhanced C-1 oxidation of glucose) and was due to "perforation from within" of the lysosomal membrane, rather than lysis by crystals of the plasma membrane. Enzyme release after MSU ingestion was also reduced when cells were treated with pharmacological doses of the test agents. When cells were killed by Triton X-100, acting on the plasma membrane, C-1 oxidation of glucose was abolished and enzyme release could not be inhibited pharmacologically. These observations suggest that lysosomal enzyme release from human phagocytes can be an active process which accompanies plasma membrane stimulation, is independent of cell death, and may be controlled by cyclic nucleotides and agents which affect microtubules. PMID:4125373

Zurier, Robert B.; Hoffstein, Sylvia; Weissmann, Gerald

1973-01-01

152

Enzyme activity determination using ultrasound  

NASA Astrophysics Data System (ADS)

Here are presented the results of a novel approach to the measurement of enzyme reaction rates in which ultrasound velocity measurement is used. Our results show enzyme activity is observable, in the acoustic context, and that furthermore this offers the potential to estimate the rate of reaction over different substrate concentrations and temperatures. Findings are corroborated with optical microscopy and rheological measurements. Ultrasound velocity measurement can be performed without the need for aliquot extraction and offers an efficient, non-invasive and dynamic method to monitor enzyme activity.

Holmes, M. J.; Southworth, T.; Watson, N. G.; Povey, M. J. W.

2014-04-01

153

The Wilderness Act Handbook  

NSDL National Science Digital Library

From the Wilderness Society, this 40th anniversary edition of _The Wilderness Act Handbook_ was released in May of 2004. The Handbook "sets forth the relevant laws, regulations, and policies that govern the creation, expansion, and management of the National Wilderness Preservation System. The Wilderness Act is printed out in its entirety, along with interpretation and excerpts from and analysis of subsequent legislation that has influenced the designation or management of wilderness." The 90-page pdf document contains sections on Designating New Wilderness Areas, Wilderness Management and Stewardship, National Wildlife Refuge Wilderness, National Forest Wilderness, Wilderness Myths, and more. The Handbook includes a Wilderness Reading List as well. A text-only version of the Handbook is also available for download.

154

Toxic Substances Control Act  

SciTech Connect

This Reference Book contains a current copy of the Toxic Substances Control Act and those regulations that implement the statute and appear to be most relevant to DOE activities. The document is provided to DOE and contractor staff for informational purposes only and should not be interpreted as legal guidance. Questions concerning this Reference Book may be directed to Mark Petts, EH-231 (202/586-2609).

Not Available

1992-05-15

155

The ACTS multibeam antenna  

NASA Technical Reports Server (NTRS)

The Advanced Communications Technology Satellite (ACTS) to be launched in 1993 introduces several new technologies including a multibeam antenna (MBA) operating at Ka-band. The satellite is introduced briefly, and then the MBA, consisting of electrically similar 30 GHz received and 20 GHz transmit offset Cassegrain systems utilizing orthogonal linear polarizations, is described. Dual polarization is achieved by using one feed assembly for each polarization in conjunction with nested front and back subreflectors, the gridded front subreflector acting as a window for one polarization and a reflector for the other. The antennas produce spot beams with approximately 0.3 deg beamwidth and gains of approximately 50 dbi. High surface accuracy and high edge taper produce low sidelobe levels and high cross-polarization isolation. A brief description is given of several Ka-band components fabricated for ACTS. These include multiflare antenna feedhorns, beam-forming networks utilizing latching ferrite waveguide switches, a 30 GHz high mobility electron transmitter (HEMT) low-noise amplifier and a 20 GHz TWT power amplifier.

Regier, Frank A.

1992-01-01

156

A sweet new role for LCP enzymes in protein glycosylation.  

PubMed

The peptidoglycan that surrounds Gram-positive bacteria is affixed with a range of macromolecules that enable the microbe to effectively interact with its environment. Distinct enzymes decorate the cell wall with proteins and glycopolymers. Sortase enzymes covalently attach proteins to the peptidoglycan, while LytR-CpsA-Psr (LCP) proteins are thought to attach teichoic acid polymers and capsular polysaccharides. Ton-That and colleagues have discovered a new glycosylation pathway in the oral bacterium Actinomyces oris in which sortase and LCP enzymes operate on the same protein substrate. The A. oris?LCP protein has a novel function, acting on the cell surface to transfer glycan macromolecules to a protein, which is then attached to the cell wall by a sortase. The reactions are tightly coupled, as elimination of the sortase causes the lethal accumulation of glycosylated protein in the membrane. Since sortase enzymes are attractive drug targets, this novel finding may provide a convenient cell-based tool to discover inhibitors of this important enzyme family. PMID:25302626

Amer, Brendan R; Clubb, Robert T

2014-12-01

157

ENZYME TESTING LABS German Linguistic Tester  

E-print Network

ENZYME TESTING LABS German Linguistic Tester Under supervision of the Project Manager, the Tester as possible Please apply via our website: www.enzyme.org or contact us by email at jobs@enzyme.org #12;

158

ORGANOPHOSPHATE DEGRADING ENZYMES - PHASE I  

EPA Science Inventory

Agave BioSystems in collaboration with Carl A. Batt proposes to develop decon-nanoparticles, which will leverage ongoing opportunities in enzyme engineering and the fabrication of functionalized magnetic nanoparticles. Enhanced performance will be engineered into the system t...

159

Molybdenum enzymes in higher organisms  

PubMed Central

Recent progress in our understanding of the structural and catalytic properties of molybdenum-containing enzymes in eukaryotes is reviewed, along with aspects of the biosynthesis of the cofactor and its insertion into apoprotein. PMID:21516203

Hille, Russ; Nishino, Takeshi; Bittner, Florian

2010-01-01

160

Enzyme nomenclature: Functional or structural?  

E-print Network

Altman and colleagues (this issue) call attention to the inability of current standardized enzyme nomenclature to distinguish between enzymatic activities that reside in nonhomologous macromolecules. This issue is highlighted by the fact...

Gegenheimer, Peter Albert

2000-12-01

161

Regulation of Proteolysis by Human Deubiquitinating Enzymes  

PubMed Central

The post-translational attachment of one or several ubiquitin molecules to a protein generates a variety of targeting signals that are used in many different ways in the cell. Ubiquitination can alter the activity, localization, protein-protein interactions or stability of the targeted protein. Further, a very large number of proteins are subject to regulation by ubiquitin-dependent processes, meaning that virtually all cellular functions are impacted by these pathways. Nearly a hundred enzymes from five different gene families (the deubiquitinating enzymes or DUBs), reverse this modification by hydrolyzing the (iso)peptide bond tethering ubiquitin to itself or the target protein. Four of these families are thiol proteases and one is a metalloprotease. DUBs of the Ubiquitin C-terminal Hydrolase (UCH) family act on small molecule adducts of ubiquitin, process the ubiquitin proprotein, and trim ubiquitin from the distal end of a polyubiquitin chain. Ubiquitin Specific Proteases (USP) tend to recognize and encounter their substrates by interaction of the variable regions of their sequence with the substrate protein directly, or with scaffolds or substrate adapters in multiprotein complexes. Ovarian Tumor (OTU) domain DUBs show remarkable specificity for different Ub chain linkages and may have evolved to recognize substrates on the basis of those linkages. The Josephin family of DUBs may specialize in distinguishing between polyubiquitin chains of different lengths. Finally, the JAB1/MPN+/MOV34 (JAMM) domain metalloproteases cleave the isopeptide bond near the attachment point of polyubiquitin and substrate, as well as being highly specific for the K63 poly-Ub linkage. These DUBs regulate proteolysis by: directly interacting with and co-regulating E3 ligases; altering the level of substrate ubiquitination; hydrolyzing or remodeling ubiquitinated and poly-ubiquitinated substrates; acting in specific locations in the cell and altering the localization of the target protein; and acting on proteasome bound substrates to facilitate or inhibit proteolysis. Thus, the scope and regulation of the ubiquitin pathway is very similar to that of phosphorylation, with the DUBs serving the same functions as the phosphatase. PMID:23845989

Eletr, Ziad M.; Wilkinson, Keith D.

2013-01-01

162

Proteolytic enzymes of Phymatotrichum omnivorum  

E-print Network

PROTEOLYTIC ENZYMES OF PHYMATOTRICHUM OMNIVORUM A Thesis Alexis Burgum Submit'ted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE january 1964 Major Subject...: Biochemistry and Nutrition PROTEOLYTIC ENZYMES OF PHYMATOTRICHUM OMNIVORUM A Thesis by Alexis Burgum Approved as to style and content by: rman o ommr ee ea o epart t) e er m er em er em er /' r Member january 1964 ACKNOWLEDCEMENTS The author...

Burgum, Alexis August

1964-01-01

163

Amidases: versatile enzymes in nature  

Microsoft Academic Search

Amidases are ubiquitous enzymes and biological functions of these enzymes vary widely. In past five decades, they turned out\\u000a to be an attractive tool in industries for the synthesis of wide variety of carboxylic acids, hydroxamic acids and hydrazide,\\u000a which find applications in commodity chemicals synthesis, pharmaceuticals agrochemicals and waste water treatments etc. Their\\u000a proteins structures revealed that aliphatic amidases

Monica Sharma; Nitya Nand Sharma; Tek Chand Bhalla

2009-01-01

164

Americans with Disabilities Act and Architectural Barriers Act  

E-print Network

Americans with Disabilities Act and Architectural Barriers Act Accessibility Guidelines July 23 for standards used to enforce the ADA h O access for people with disabilities under the Americans with Disabilities Act (ADA). These guidelines update access requirements for a wide range of facilities in the pub

Mathis, Wayne N.

165

7 CFR 33.1 - Act.  

Code of Federal Regulations, 2014 CFR

...REGULATIONS ISSUED UNDER AUTHORITY OF THE EXPORT APPLE ACT Definitions § 33.1 Act. Act and Export Apple Act are synonymous and mean “An act...the foreign trade of the United States in apples to protect the reputation of...

2014-01-01

166

7 CFR 33.1 - Act.  

Code of Federal Regulations, 2012 CFR

...REGULATIONS ISSUED UNDER AUTHORITY OF THE EXPORT APPLE ACT Definitions § 33.1 Act. Act and Export Apple Act are synonymous and mean “An act...the foreign trade of the United States in apples to protect the reputation of...

2012-01-01

167

7 CFR 33.1 - Act.  

Code of Federal Regulations, 2013 CFR

...REGULATIONS ISSUED UNDER AUTHORITY OF THE EXPORT APPLE ACT Definitions § 33.1 Act. Act and Export Apple Act are synonymous and mean “An act...the foreign trade of the United States in apples to protect the reputation of...

2013-01-01

168

7 CFR 33.1 - Act.  

Code of Federal Regulations, 2011 CFR

...REGULATIONS ISSUED UNDER AUTHORITY OF THE EXPORT APPLE ACT Definitions § 33.1 Act. Act and Export Apple Act are synonymous and mean “An act...the foreign trade of the United States in apples to protect the reputation of...

2011-01-01

169

7 CFR 33.1 - Act.  

Code of Federal Regulations, 2010 CFR

...REGULATIONS ISSUED UNDER AUTHORITY OF THE EXPORT APPLE ACT Definitions § 33.1 Act. Act and Export Apple Act are synonymous and mean “An act...the foreign trade of the United States in apples to protect the reputation of...

2010-01-01

170

The Role of ACT-Like Subdomain in Bacterial Threonine Dehydratases  

PubMed Central

In bacteria, threonine dehydratases could convert L-threonine to 2-ketobutyrate. Some threonine dehydratases contain only a catalytic domain, while others contain an N-terminal catalytic domain and a C-terminal regulatory domain composed of one or two ACT-like subdomains. However, the role of the ACT-like subdomain in threonine dehydratases is not clear. Here, nine different bacterial threonine dehydratases were studied. Three of the nine contain no ACT-like subdomain, four of them contain a single ACT-like subdomain, and two of them contain two ACT-like subdomains. The nine genes encoding these threonine dehydratases were individually overexpressed in E. coli BL21(DE3), and the enzymes were purified to homogeneity. Activities of the purified enzymes were analyzed after incubation at different temperatures and different pHs. The results showed that threonine dehydratases with a single ACT-like subdomain are more stable at higher temperatures and a broad range of pH than those without ACT-like subdomain or with two ACT-like subdomains. Furthermore, the specific activity of threonine dehydratases increases with the increase of the number of ACT-like subdomains they contain. The results suggest that the ACT-like subdomain plays an important role in bacterial threonine dehydratases. PMID:24475306

Yu, Xuefei; Li, Yanyan; Wang, Xiaoyuan

2014-01-01

171

Cleaning Up Your Act  

NSDL National Science Digital Library

Cleaning Up Your Act Model Eliciting Activity (MEA) provides students with a real world engineering problem in which they must work as a team to design a procedure to select the best material for cleaning up an oil spill. The main focus of this MEA is to recognize the consequences of a catastrophic event, and understand the environmental and economical impact based on data analysis. Students will conduct individual and team investigations in order to arrive at a scientifically sound solution to the problem.

Donna King

2012-08-01

172

Quick acting gimbal joint  

NASA Technical Reports Server (NTRS)

The present invention relates to an adjustable linkage assembly for selectively retaining the position of one member pivotable with respect to another member. More specifically, the invention relates to a linkage assembly commonly referred to as a gimbal joint, and particularly to a quick release or quick acting gimbal joint. The assembly is relatively simple in construction, compact in size, and has superior locking strength in any selected position. The device can be quickly and easily actuated, without separate tooling, by inexperienced personnel or by computer controlled equipment. It also is designed to prevent inadvertent actuation.

Wood, William B. (inventor); Krch, Gary D. (inventor)

1993-01-01

173

Family and Medical Leave Act  

MedlinePLUS

... CARING FOR A CHILD: FAMILY & MEDICAL LEAVE ACT If your child's heart condition is serious and ... in the hospital, the Family and Medical Leave Act of 1993 requires that covered employers provide up ...

174

PROHIBITED ACTSPROHIBITED ACTS (a) GENERAL.-  

E-print Network

) and 10 of this Act, with respect to any endangered species of fish or wildlife listed pursuant to section) Except as provided in sections 6(g)(2) and 10 of this Act, with respect to any endangered species or in a controlled environment on the effective date of the Endangered Species Act Amendments of 1978; or #12;(ii

175

ACTS broadband aeronautical experiment  

NASA Technical Reports Server (NTRS)

In the last decade, the demand for reliable data, voice, and video satellite communication links between aircraft and ground to improve air traffic control, airline management, and to meet the growing demand for passenger communications has increased significantly. It is expected that in the near future, the spectrum required for aeronautical communication services will grow significantly beyond that currently available at L-band. In anticipation of this, JPL is developing an experimental broadband aeronautical satellite communications system that will utilize NASA's Advanced Communications Technology Satellite (ACTS) as a satellite of opportunity and the technology developed under JPL's ACTS Mobile Terminal (AMT) Task to evaluate the feasibility of using K/Ka-band for these applications. The application of K/Ka-band for aeronautical satellite communications at cruise altitudes is particularly promising for several reasons: (1) the minimal amount of signal attenuation due to rain; (2) the reduced drag due to the smaller K/Ka-band antennas (as compared to the current L-band systems); and (3) the large amount of available bandwidth. The increased bandwidth available at these frequencies is expected to lead to significantly improved passenger communications - including full-duplex compressed video and multiple channel voice. A description of the proposed broadband experimental system will be presented including: (1) applications of K/Ka-band aeronautical satellite technology to U.S. industry; (2) the experiment objectives; (3) the experiment set-up; (4) experimental equipment description; and (5) industrial participation in the experiment and the benefits.

Abbe, Brian S.; Jedrey, Thomas C.; Estabrook, Polly; Agan, Martin J.

1993-01-01

176

Hard ACTS to follow  

NASA Astrophysics Data System (ADS)

The Advanced Communications Technology Satellite (ACTS), the third phase of NASA's 30/20 GHz satellite communications program, is praised for its frugal usage of both the geosynchronous orbital arch and the frequency spectrum resources necessary for communications satellites. Its objective is to verify Ka-band satellite communications concepts and to develop a flight and ground system for validation of the multibeam communications proof-of-concept technologies. The ACTS ground segment (comprised of four types of terminals) is designed to compliment the spacecraft for the SS launch in 1989. Precise coordination between the ground and spacecraft segments is performed by the baseband processor (BBP), which is an in-orbit switchboard, and the tracking error word, which enables the ground terminals to remain synchronized with onboard timing. Fixed spot beams and scan beams, comprising the two types of spot beams used, both operate at the same frequency and hence, conserve frequency resources. In addition, the time division multiple access serves to enhance system efficiency. It is concluded that Ka-band satellites are a practical approach to the better usage of those resources potentially threatened by communications satellites. Comprehensive graphs and block diagrams of the system are included.

Moy, L.

1986-05-01

177

Molecular Biology Basics Planning Restriction Enzyme Digests  

E-print Network

Molecular Biology Basics Planning Restriction Enzyme Digests A. Checklist: Buffer type Addition of BSA Optimum temperature Number of units of enzyme B. Plan to digest DNA with an "excess" of enzyme activity. Plan for the "excess" to be divided between time of digestion and number of units of enzyme

Aris, John P.

178

Enzyme-Based Listericidal Nanocomposites  

PubMed Central

Cell lytic enzymes represent an alternative to chemical decontamination or use of antibiotics to kill pathogenic bacteria, such as listeria. A number of phage cell lytic enzymes against listeria have been isolated and possess listericidal activity; however, there has been no attempt to incorporate these enzymes onto surfaces. We report three facile routes for the surface incorporation of the listeria bacteriophage endolysin Ply500: covalent attachment onto FDA approved silica nanoparticles (SNPs), incorporation of SNP-Ply500 conjugates into a thin poly(hydroxyethyl methacrylate) film; and affinity binding to edible crosslinked starch nanoparticles via construction of a maltose binding protein fusion. These Ply500 formulations were effective in killing L. innocua (a reduced pathogenic surrogate) at challenges up to 105?CFU/ml both in non-growth sustaining PBS as well as under growth conditions on lettuce. This strategy represents a new route toward achieving highly selective and efficient pathogen decontamination and prevention in public infrastructure. PMID:23545700

Solanki, Kusum; Grover, Navdeep; Downs, Patrick; Paskaleva, Elena E.; Mehta, Krunal K.; Lee, Lillian; Schadler, Linda S.; Kane, Ravi S.; Dordick, Jonathan S.

2013-01-01

179

Evolutionary aspects of enzyme dynamics.  

PubMed

The role of evolutionary pressure on the chemical step catalyzed by enzymes is somewhat enigmatic, in part because chemistry is not rate-limiting for many optimized systems. Herein, we present studies that examine various aspects of the evolutionary relationship between protein dynamics and the chemical step in two paradigmatic enzyme families, dihydrofolate reductases and alcohol dehydrogenases. Molecular details of both convergent and divergent evolution are beginning to emerge. The findings suggest that protein dynamics across an entire enzyme can play a role in adaptation to differing physiological conditions. The growing tool kit of kinetics, kinetic isotope effects, molecular biology, biophysics, and bioinformatics provides means to link evolutionary changes in structure-dynamics function to the vibrational and conformational states of each protein. PMID:25210031

Klinman, Judith P; Kohen, Amnon

2014-10-31

180

Subcellular localization of pituitary enzymes  

NASA Technical Reports Server (NTRS)

A cytochemical procedure is reported for identifying subcellular sites of enzymes hydrolyzing beta-naphthylamine substrates, and to study the sites of reaction product localization in cells of various tissues. Investigations using the substrate Leu 4-methoxy-8-naphthylamine, a capture with hexonium pararosaniline, and the final chelation of osmium have identified the hydrolyzing enzyme of rat liver cells; this enzyme localized on cell membranes with intense deposition in the areas of the parcanaliculi. The study of cells in the anterior pituitary of the rat showed the deposition of reaction product on cell membrane; and on the membranes of secretion granules contained within the cell. The deposition of reaction product on the cell membrane however showed no increase or decrease with changes in the physiological state of the gland and release of secretion granules from specific cells.

Smith, R. E.

1970-01-01

181

Macromolecular juggling by ubiquitylation enzymes  

PubMed Central

The posttranslational modification of target proteins with ubiquitin and ubiquitin-like proteins is accomplished by the sequential action of E1, E2, and E3 enzymes. Members of the E1 and E3 enzyme families can undergo particularly large conformational changes during their catalytic cycles, involving the remodeling of domain interfaces. This enables the efficient, directed and regulated handover of ubiquitin from one carrier to the next one. We review some of these conformational transformations, as revealed by crystallographic studies. PMID:23800009

2013-01-01

182

Enzyme Catalysis in Organic Synthesis  

NASA Astrophysics Data System (ADS)

The present state of enzyme catalysis and the prospects for its introduction in organic synthesis are examined. The physicochemical approaches whereby the yield of the desired product can be increased under conditions favourable for biocatalysis (at the optimum of the catalytic activity and stability of the enzyme) are analysed. Together with classical equilibrium and kinetic preparative methods, the thermodynamic features and general methodological aspects of a new approach — enzymatic synthesis in two-phase systems comprising water and a water-immiscible organic solvent — are discussed in detail. The bibliography includes 170 references.

Martinek, K.; Semenov, A. N.

1981-08-01

183

Caught in the Act  

NASA Technical Reports Server (NTRS)

5 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a dust devil caught in the act of creating a dark streak on the floor of the large, south mid-latitude crater, Mendel. Dozens of other dark streaks mark the paths of earlier dust devils. Dust devil streaks at southern middle and high latitudes are seasonal features; they are erased each winter by thin deposits of dust and frost, and they are re-created each spring and summer by new dust devils.

Location near: 58.9oS, 199.4oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

2005-01-01

184

Triple acting radial seal  

DOEpatents

A triple acting radial seal used as an interstage seal assembly in a gas turbine engine, where the seal assembly includes an interstage seal support extending from a stationary inner shroud of a vane ring, the interstage seal support includes a larger annular radial inward facing groove in which an outer annular floating seal assembly is secured for radial displacement, and the outer annular floating seal assembly includes a smaller annular radial inward facing groove in which an inner annular floating seal assembly is secured also for radial displacement. A compliant seal is secured to the inner annular floating seal assembly. The outer annular floating seal assembly encapsulates the inner annular floating seal assembly which is made from a very low alpha material in order to reduce thermal stress.

Ebert, Todd A (West Palm Beach, FL); Carella, John A (Jupiter, FL)

2012-03-13

185

ACTS mobile propagation campaign  

NASA Technical Reports Server (NTRS)

Preliminary results are presented for three propagation measurement campaigns involving a mobile receiving laboratory and 20 GHz transmissions from the Advanced Communications Technology Satellite (ACTS). Four 1994 campaigns were executed during weekly periods in and around Austin, Texas in February and May, in Central Maryland during March, and in Fairbanks, Alaska and environs in June. Measurements tested the following effects at 20 GHz: (1) attenuation due to roadside trees with and without foliage, (2) multipath effects for scenarios in which line-of-sight paths were unshadowed, (3) fades due to terrain and roadside obstacles, (4) fades due to structures in urban environs, (5) single tree attenuation, and (6) effects of fading at low elevation angles (8 deg in Fairbanks, Alaska) and high elevation angles (55 deg in Austin, Texas). Results presented here cover sampled measurements in Austin, Texas for foliage and non-foliage cases and in Central Maryland for non-foliage runs.

Goldhirsh, Julius; Vogel, Wolfhard J.; Torrence, Geoffrey W.

1994-01-01

186

Thermodynamics of Enzyme-Catalyzed Reactions Database  

National Institute of Standards and Technology Data Gateway

SRD 74 Thermodynamics of Enzyme-Catalyzed Reactions Database (Web, free access)   The Thermodynamics of Enzyme-Catalyzed Reactions Database contains thermodynamic data on enzyme-catalyzed reactions that have been recently published in the Journal of Physical and Chemical Reference Data (JPCRD). For each reaction the following information is provided: the reference for the data, the reaction studied, the name of the enzyme used and its Enzyme Commission number, the method of measurement, the data and an evaluation thereof.

187

Enzyme-linked enzyme binding assay for Pin1 WW domain ligands  

PubMed Central

Peptidyl prolyl cis-trans isomerase (PPIase) interacting with NIMA-1 (Pin1) catalyzes the cis-trans isomerization of pSer/pThr–Pro amide bonds. Pin1 is a two-domain protein that represents a promising target for the treatment of cancer. Both domains of Pin1 bind the pSer/pThr–Pro motif; PPIase enzymatic activity occurs in the catalytic domain, and the WW domain acts as a recognition module for the pSer/pThr–Pro motif. An assay we call an Enzyme-Linked Enzyme Binding Assay (ELEBA), was developed to measure the Kd of ligands that bind selectively to the WW domain. A ligand specific for the WW domain of Pin1 was covalently immobilized in a 96-well plate. Commercially available Pin1 conjugated to horseradish peroxidase was used for chemiluminescent detection of ligands that block the association of the WW domain with immobilized ligand. The peptide ligands were derived from the cell cycle regulatory phosphatase, Cdc25c, residues 45-50. The Kd values for Fmoc–VPRpTPVGGGK–NH2 and Ac–VPRpTPV–NH2 were determined to be 36 ± 4 ?M and 110 ± 30 ?M respectively. The ELEBA offers a selective approach to detect ligands that bind to the Pin1 WW domain, even in the presence of the catalytic domain. This method may be applied to any dual specificity, multi-domain protein. PMID:20230769

Mercedes-Camacho, Ana Y.; Etzkorn, Felicia A.

2010-01-01

188

EzCatDB: the enzyme reaction database, 2015 update  

PubMed Central

The EzCatDB database (http://ezcatdb.cbrc.jp/EzCatDB/) has emphasized manual classification of enzyme reactions from the viewpoints of enzyme active-site structures and their catalytic mechanisms based on literature information, amino acid sequences of enzymes (UniProtKB) and the corresponding tertiary structures from the Protein Data Bank (PDB). Reaction types such as hydrolysis, transfer, addition, elimination, isomerization, hydride transfer and electron transfer have been included in the reaction classification, RLCP. This database includes information related to ligand molecules on the enzyme structures in the PDB data, classified in terms of cofactors, substrates, products and intermediates, which are also necessary to elucidate the catalytic mechanisms. Recently, the database system was updated. The 3D structures of active sites for each PDB entry can be viewed using Jmol or Rasmol software. Moreover, sequence search systems of two types were developed for the EzCatDB database: EzCat-BLAST and EzCat-FORTE. EzCat-BLAST is suitable for quick searches, adopting the BLAST algorithm, whereas EzCat-FORTE is more suitable for detecting remote homologues, adopting the algorithm for FORTE protein structure prediction software. Another system, EzMetAct, is also available to searching for major active-site structures in EzCatDB, for which PDB-formatted queries can be searched. PMID:25324316

Nagano, Nozomi; Nakayama, Naoko; Ikeda, Kazuyoshi; Fukuie, Masaru; Yokota, Kiyonobu; Doi, Takuo; Kato, Tsuyoshi; Tomii, Kentaro

2015-01-01

189

EzCatDB: the enzyme reaction database, 2015 update.  

PubMed

The EzCatDB database (http://ezcatdb.cbrc.jp/EzCatDB/) has emphasized manual classification of enzyme reactions from the viewpoints of enzyme active-site structures and their catalytic mechanisms based on literature information, amino acid sequences of enzymes (UniProtKB) and the corresponding tertiary structures from the Protein Data Bank (PDB). Reaction types such as hydrolysis, transfer, addition, elimination, isomerization, hydride transfer and electron transfer have been included in the reaction classification, RLCP. This database includes information related to ligand molecules on the enzyme structures in the PDB data, classified in terms of cofactors, substrates, products and intermediates, which are also necessary to elucidate the catalytic mechanisms. Recently, the database system was updated. The 3D structures of active sites for each PDB entry can be viewed using Jmol or Rasmol software. Moreover, sequence search systems of two types were developed for the EzCatDB database: EzCat-BLAST and EzCat-FORTE. EzCat-BLAST is suitable for quick searches, adopting the BLAST algorithm, whereas EzCat-FORTE is more suitable for detecting remote homologues, adopting the algorithm for FORTE protein structure prediction software. Another system, EzMetAct, is also available to searching for major active-site structures in EzCatDB, for which PDB-formatted queries can be searched. PMID:25324316

Nagano, Nozomi; Nakayama, Naoko; Ikeda, Kazuyoshi; Fukuie, Masaru; Yokota, Kiyonobu; Doi, Takuo; Kato, Tsuyoshi; Tomii, Kentaro

2015-01-01

190

Inhibitors of testosterone biosynthetic and metabolic activation enzymes.  

PubMed

The Leydig cells of the testis have the capacity to biosynthesize testosterone from cholesterol. Testosterone and its metabolically activated product dihydrotestosterone are critical for the development of male reproductive system and spermatogenesis. At least four steroidogenic enzymes are involved in testosterone biosynthesis: Cholesterol side chain cleavage enzyme (CYP11A1) for the conversion of cholesterol into pregnenolone within the mitochondria, 3?-hydroxysteroid dehydrogenase (HSD3B), for the conversion of pregnenolone into progesterone, 17?-hydroxylase/17,20-lyase (CYP17A1) for the conversion of progesterone into androstenedione and 17?-hydroxysteroid dehydrogenase (HSD17B3) for the formation of testosterone from androstenedione. Testosterone is also metabolically activated into more potent androgen dihydrotestosterone by two isoforms 5?-reductase 1 (SRD5A1) and 2 (SRD5A2) in Leydig cells and peripheral tissues. Many endocrine disruptors act as antiandrogens via directly inhibiting one or more enzymes for testosterone biosynthesis and metabolic activation. These chemicals include industrial materials (perfluoroalkyl compounds, phthalates, bisphenol A and benzophenone) and pesticides/biocides (methoxychlor, organotins, 1,2-dibromo-3-chloropropane and prochloraz) and plant constituents (genistein and gossypol). This paper reviews these endocrine disruptors targeting steroidogenic enzymes. PMID:22138857

Ye, Leping; Su, Zhi-Jian; Ge, Ren-Shan

2011-01-01

191

Novel cyanide-hydrolyzing enzyme from Alcaligenes xylosoxidans subsp. denitrificans  

SciTech Connect

A cyanide-metabolizing bacterium, strain DF3, isolated from soil was identified as Alcaligenes xylosoxidans subsp. denitrificans. Whole cells and cell extracts of strain DF3 catalyzed hydrolysis of cyanide to formate and ammonia (HCN + 2H{sub 2}O {r arrow} HCOOH + NH{sub 3}) without forming formamide as a free intermediate. The cyanide-hydrolyzing activity was inducibly produced in cells during growth in cyanide-containing media. Cyanate (OCN{sup {minus}}) and a wide range of aliphatic and aromatic nitriles were not hydrolyzed by intact cells of A. xylosoxidans subsp. denitrificans DF3. Strain DF3 hydrolyzed cyanide with great efficacy. Thus, by using resting induced cells at a concentration of 11.3 mg (dry weight) per ml, the cyanide concentration could be reduced from 0.97 M (approximately 25,220 ppm) to less than 77 nM (approximately 0.002 ppm) in 55 h. Enzyme purification established that cyanide hydrolysis by A. xylosoxidans subsp. denitrificans DF3 was due to a single intracellular enzyme. The molecular mass of the active enzyme (purity, {gt}97% as determined by amino acid sequencing) was estimated to be {gt}300,000 Da. The cyanide-hydrolyzing enzyme of A. xylosoxidans subsp. denitrificans DF3 was tentatively named cyanidase to distinguish it from known nitrilases (EC 3.5.5.1) which act on organic nitriles.

Ingvorsen, K.; Hojer-Pederson, B.; Godtfredsen, S.E. (Novo Nordisk A/S, Bagsvaerd (Denmark))

1991-06-01

192

Reproducible EnzymeReproducible Enzyme Assembly and CatalyticAssembly and Catalytic  

E-print Network

Reproducible EnzymeReproducible Enzyme Assembly and CatalyticAssembly and Catalytic Activity Accomplishments #12;Reproducible Enzyme Assembly and CatalyticReproducible Enzyme Assembly and Catalytic Activity in Reusable BioMEMSActivity in Reusable BioMEMS Accomplishment Pro-tagged Pfs enzymes are spatially assembled

Rubloff, Gary W.

193

Enzyme-enabled responsive surfaces for anti-contamination materials.  

PubMed

Many real-life stains have origins from biological matters including proteins, lipids, and carbohydrates that act as gluing agents binding along with other particulates or microbes to exposed surfaces of automobiles, furniture, and fabrics. Mimicking naturally occurring self-defensive processes, we demonstrate in this work that a solid surface carrying partially exposed enzyme granules protected the surface in situ from contamination by biological stains and fingerprints. Attributed to the activities of enzymes which can be made compatible with a wide range of materials, such anti-contamination and self-cleaning functionalities are highly selective and efficient toward sticky chemicals. This observation promises a new mechanism in developing smart materials with desired anti-microbial, self-reporting, self-cleaning, or self-healing functions. PMID:23335427

Wu, Songtao; Buthe, Andreas; Jia, Hongfei; Zhang, Minjuan; Ishii, Masahiko; Wang, Ping

2013-06-01

194

Effects of Environment on Enzymes  

NSDL National Science Digital Library

The purpose of this lesson is to help students understand the cellular environment needed for enzymes to work and how it relates to cell activity. This level 4 inquiry activity was developed by a K-12 science teacher in the American Physiological SocietyÂ?s 2010 Frontiers in Physiology Program. For more information on this program, please visit www.frontiersinphys.org.

Ms. Georgia Everett (Tri-Central Community Schools)

2011-04-01

195

Insolubilized enzymes for food synthesis  

NASA Technical Reports Server (NTRS)

Cellulose matrix with numerous enzyme-coated silica particles of colloidal size permanently bound at various sites within matrix was produced that has high activity and possesses requisite physical characteristics for filtration or column operations. Product also allows coupling step in synthesis of edible food to proceed under mild conditions.

Marshall, D. L.

1972-01-01

196

A Perspective on Enzyme Catalysis  

NSDL National Science Digital Library

The seminal hypotheses proposed over the years for enzymatic catalysis are scrutinized. The historical record is explored from both biochemical and theoretical perspectives. Particular attention is given to the impact of molecular motions within the protein on the enzyme's catalytic properties.

Stephen J. Benkovic (Pensylvania State University; Department of Chemistry)

2003-08-29

197

The enzymes associated with denitrification  

NASA Technical Reports Server (NTRS)

The enzymes involved in the reduction of nitrogenous oxides are thought to be intermediates in denitrification processes. This review examines the roles of nitrate reductase, nitrite reductases, nitric oxide reductase, mechanisms of N-N bond formation, and nitrous oxide reductases.

Hochstein, L. I.; Tomlinson, G. A.

1988-01-01

198

Rapid-Equilibrium Enzyme Kinetics  

ERIC Educational Resources Information Center

Rapid-equilibrium rate equations for enzyme-catalyzed reactions are especially useful because if experimental data can be fit by these simpler rate equations, the Michaelis constants can be interpreted as equilibrium constants. However, for some reactions it is necessary to use the more complicated steady-state rate equations. Thermodynamics is…

Alberty, Robert A.

2008-01-01

199

Antioxidant enzymes and human diseases  

Microsoft Academic Search

Objectives: To describe the importance of the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and catalase working together in human cells against toxic reactive oxygen species, their relationship with several pathophysiologic processes and their possible therapeutic implications.Conclusions: Reactive oxygen species (ROS) are involved in the cell growth, differentiation, progression, and death. Low concentrations of ROS may be beneficial or even indispensable

JosÉ M. MatÉs; Cristina Pérez-Gómez; Ignacio Núńez De Castro

1999-01-01

200

Rennin--a Neglected Enzyme?  

ERIC Educational Resources Information Center

Presents investigations to explore the substrate specificity, pH, concentration, and temperature relations of an enzyme with only inexpensive commercial rennet and basic laboratory equipment. Describes how the activities were carried out with a group of 15-year-old students. (CW)

Gill, John; Saunders, Terry

1987-01-01

201

Nutrition and Pancreatic Enzyme Replacement in People with Cystic Fibrosis  

MedlinePLUS

... CF digest and absorb their food. What Are Enzymes And How Do They Work? Pancreatic enzyme replacements ... have CF take pancreatic enzyme replacements. How Are Enzymes Given? Enzymes should be taken just before meals ...

202

A GENETIC ANALYSIS OF THE PTERIDINE BIOSYNTHETIC ENZYME, GUANOSINE TRIPHOSPHATE CYCLOHYDROLASE, IN DROSOPHILA MELANOGASTER  

Microsoft Academic Search

Strains with mutant eye color were surveyed for levels of GTP cyclohydro- lase (GTP CH), the first enzyme acting in the biosynthesis of pteridines, the pigments causing red eye color in Drosophila. Six strains were found to have reduced GTP CH activity. In five of the six strains, the reduction of activity is apparent only in the adult head of

WILLIAM J. MACKAY; JANIS M. O'DONNELL

203

Automethylation of protein ( d -aspartyl\\/ l -isoaspartyl) carboxyl methyltransferase, a response to enzyme aging  

Microsoft Academic Search

A question that is central to understanding the mechanisms of aging and cellular deterioration is whether enzymes involved in recognition and metabolism of spontaneously damaged proteins are themselves damaged, either becoming substrates for their own activity; or being unable to act upon themselves, initiating cascades of cellular damage. We show here byin vitro experiments that protein (d-aspartyl\\/l-isoaspartyl) carboxyl methyltransferase (PCM)

Jonathan A. Lindquist; Philip N. McFadden

1994-01-01

204

Characterization of fish-skin gelatin gels and films containing the antomicrobial enzyme lysozyme  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fish skins are rich in collagen and can be used to produce food-grade gelatin. Films cast from fish-skin gelatins are stable at room temperature and can act as a barrier when applied to foods. Lysozyme is a food-safe, antimicrobial enzyme that can also produce gels and films. When cold-water, fish-s...

205

Decreased Bone Density in Splenectomized Gaucher Patients Receiving Enzyme Replacement Therapy  

Microsoft Academic Search

ABSTRACTLittle is known about the effect of enzyme replacement therapy (ERT) on the bone abnormalities in Gaucher disease. Splenectomized Gaucher patients tend to suffer the most severe skeletal complications. We hypothesized that vitamin D supplementation would act synergistically with glucocerebrosidase infusions to increase bone density in splenectomized Gaucher patients. In a 24-month study, 29 splenectomized Gaucher patients were randomized to

Raphael Schiffmann; Henry Mankin; James M Dambrosia; Ramnik J Xavier; Constance Kreps; Suvimol C Hill; Norman W Barton; Daniel I Rosenthal

2002-01-01

206

Using amphiphilic pseudo amino acid composition to predict enzyme subfamily classes  

Microsoft Academic Search

Abstract Motivation: With the protein sequences entering into databanks at an explosive pace, it is important to timely determine the family or subfamily class for a newly-found enzyme molecule because this is directly related to the detailed information about what specific target it acts on, as well as to its catalytic process and biological function. Unfortunately, it is both time-consuming

Kuo-chen Chou

2005-01-01

207

Fast-Acting Valve  

NASA Technical Reports Server (NTRS)

A fast-acting valve includes an annular valve seat that defines an annular valve orifice between the edges of the annular valve seat, an annular valve plug sized to cover the valve orifice when the valve is closed, and a valve-plug holder for moving the annular valve plug on and off the annular valve seat. The use of an annular orifice reduces the characteristic distance between the edges of the valve seat. Rather than this distance being equal to the diameter of the orifice, as it is for a conventional circular orifice, the characteristic distance equals the distance between the inner and outer radii (for a circular annulus). The reduced characteristic distance greatly reduces the gap required between the annular valve plug and the annular valve seat for the valve to be fully open, thereby greatly reducing the required stroke and corresponding speed and acceleration of the annular valve plug. The use of a valve-plug holder that is under independent control to move the annular valve plug between its open and closed positions is important for achieving controllable fast operation of the valve.

Wojciechowski, Bogdan V. (Inventor); Pegg, Robert J. (Inventor)

2003-01-01

208

Acting to gain information  

NASA Technical Reports Server (NTRS)

This report is concerned with agents that act to gain information. In previous work, we developed agent models combining qualitative modeling with real-time control. That work, however, focused primarily on actions that affect physical states of the environment. The current study extends that work by explicitly considering problems of active information-gathering and by exploring specialized aspects of information-gathering in computational perception, learning, and language. In our theoretical investigations, we analyzed agents into their perceptual and action components and identified these with elements of a state-machine model of control. The mathematical properties of each was developed in isolation and interactions were then studied. We considered the complexity dimension and the uncertainty dimension and related these to intelligent-agent design issues. We also explored active information gathering in visual processing. Working within the active vision paradigm, we developed a concept of 'minimal meaningful measurements' suitable for demand-driven vision. We then developed and tested an architecture for ongoing recognition and interpretation of visual information. In the area of information gathering through learning, we explored techniques for coping with combinatorial complexity. We also explored information gathering through explicit linguistic action by considering the nature of conversational rules, coordination, and situated communication behavior.

Rosenchein, Stanley J.; Burns, J. Brian; Chapman, David; Kaelbling, Leslie P.; Kahn, Philip; Nishihara, H. Keith; Turk, Matthew

1993-01-01

209

Deep Seabed Mineral Resources Act  

Microsoft Academic Search

The Deep Seabed Mineral Resources Act, approved by the Senate Energy Committee in 1979, would permit U.S. mining interests to begin commercial recovery of hard minerals from the ocean floor. Under the proposed act, NOAA will regulate mining activities by issuing exploration licenses. The act demonstrates the U.S.'s dual commitment to a new and comprehensive internatonal law of the sea

1980-01-01

210

Simulating feedback and reversibility in substrate-enzyme reactions  

NASA Astrophysics Data System (ADS)

We extend discrete event models (DEM) of substrate-enzyme reactions to include regulatory feedback and reversible reactions. Steady state as well as transient systems are modeled and validated against ordinary differential equation (ODE) models. The approach is exemplified in a model of the first steps of glycolysis with the most common regulatory mechanisms. We find that in glycolysis, feedback and reversibility together act as a significant damper on the stochastic variations of the intermediate products as well as for the stochastic variation of the transit times. This suggests that these feedbacks have evolved to control both the overall rate of, as well as stochastic fluctuations in, glycolysis.

van Zwieten, D. A. J.; Rooda, J. E.; Armbruster, D.; Nagy, J. D.

2011-12-01

211

Enzymes and other agents that enhance cell wall extensibility  

NASA Technical Reports Server (NTRS)

Polysaccharides and proteins are secreted to the inner surface of the growing cell wall, where they assemble into a network that is mechanically strong, yet remains extensible until the cells cease growth. This review focuses on the agents that directly or indirectly enhance the extensibility properties of growing walls. The properties of expansins, endoglucanases, and xyloglucan transglycosylases are reviewed and their postulated roles in modulating wall extensibility are evaluated. A summary model for wall extension is presented, in which expansin is a primary agent of wall extension, whereas endoglucanases, xyloglucan endotransglycosylase, and other enzymes that alter wall structure act secondarily to modulate expansin action.

Cosgrove, D. J.

1999-01-01

212

Kinetic properties of a sex pheromone-degrading enzyme: the sensillar esterase of Antheraea polyphemus.  

PubMed

Behavioral and electrophysiological evidence has suggested that sex pheromone is rapidly inactivated within the sensory hairs soon after initiation of the action-potential spike. We report the isolation and characterization of a sex-pheromone-degrading enzyme from the sensory hairs of the silkmoth Antheraea polyphemus. In the presence of this enzyme at physiological concentration, the pheromone [(6E,11Z)-hexadecadienyl acetate] has an estimated half-life of 15 msec. Our findings suggest a molecular model for pheromone reception in which a previously reported pheromone-binding protein acts as a pheromone carrier, and an enzyme acts as a rapid pheromone inactivator, maintaining a low stimulus noise level within the sensory hairs. PMID:3001718

Vogt, R G; Riddiford, L M; Prestwich, G D

1985-12-01

213

Immobilization of enzymes masks their active site.  

PubMed

We studied the effect of immobilizing cellulase to carboxycellulose sodium by radiation polymerization on the masking of the active site of the enzyme. Masking of the enzyme during the preparation of immobilized enzyme was assayed at low temperature. The activity of immobilized enzyme was retained during repeated batch reactions, indicating that the enzyme was firmly trapped in the polymer matrix. Various compounds (designated monomers) were used to dissolve the carboxymethylcellulose; enzyme activity was affected by the nature of the monomer, by the monomer concentration, and by the solubility of the substrate in monomer. PMID:6722287

Kumakura, M; Kaetsu, I

1984-03-01

214

The ACT: Preparing for the ACT, 2007-2008  

ERIC Educational Resources Information Center

This booklet is intended to help students do their best on the ACT. It summarizes general test-taking strategies, describes the content of each test, provides specific tips for each, and lets students know what they can expect on test day. Included in this booklet are complete practice tests--"retired" ACT questions that were administered to…

ACT, Inc., 2007

2007-01-01

215

ACT Assessment 1996-1997: Preparing for the ACT Assessment.  

ERIC Educational Resources Information Center

The ACT Assessment is a measure of skills in English, mathematics, reading, and science reasoning necessary for college coursework. This booklet is intended to help students do their best on the ACT. It summarizes general test-taking strategies, describes the content of each of the tests, provides specific tips for each, and lets students know…

American Coll. Testing Program, Iowa City, IA.

216

7 CFR 35.1 - Act.  

Code of Federal Regulations, 2014 CFR

...STANDARD CONTAINER REGULATIONS EXPORT GRAPES AND PLUMS Definitions § 35.1 Act. Act or Export Grape and Plum Act means “An Act to promote the foreign trade of the United States in grapes and plums, to protect the...

2014-01-01

217

7 CFR 35.1 - Act.  

Code of Federal Regulations, 2011 CFR

...STANDARD CONTAINER REGULATIONS EXPORT GRAPES AND PLUMS Definitions § 35.1 Act. Act or Export Grape and Plum Act means “An Act to promote the foreign trade of the United States in grapes and plums, to protect the...

2011-01-01

218

7 CFR 35.1 - Act.  

Code of Federal Regulations, 2012 CFR

...STANDARD CONTAINER REGULATIONS EXPORT GRAPES AND PLUMS Definitions § 35.1 Act. Act or Export Grape and Plum Act means “An Act to promote the foreign trade of the United States in grapes and plums, to protect the...

2012-01-01

219

7 CFR 35.1 - Act.  

Code of Federal Regulations, 2010 CFR

...STANDARD CONTAINER REGULATIONS EXPORT GRAPES AND PLUMS Definitions § 35.1 Act. Act or Export Grape and Plum Act means “An Act to promote the foreign trade of the United States in grapes and plums, to protect the...

2010-01-01

220

7 CFR 35.1 - Act.  

Code of Federal Regulations, 2013 CFR

...STANDARD CONTAINER REGULATIONS EXPORT GRAPES AND PLUMS Definitions § 35.1 Act. Act or Export Grape and Plum Act means “An Act to promote the foreign trade of the United States in grapes and plums, to protect the...

2013-01-01

221

Mental Health Parity and Addiction Equity Act  

MedlinePLUS

... and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act of 2010 (collectively referred ... are applied indirectly in connection with the Affordable Care Act’s essential health benefit (EHB) requirements as noted below. Under the ...

222

[Euthanasia and medical act].  

PubMed

Right to life -as the prohibition of intentionally and arbitrarily taking life, even with authorization of the concerned one- is an internationally recognized right. In many countries, debate regarding euthanasia is more centered in its convenience, social acceptability and how it is regulated, than in its substantial legitimacy. Some argue that euthanasia should be included as part of clinical practice of health professionals, grounded on individual's autonomy claims-everyone having the liberty to choose how to live and how to die. Against this, others sustain that life has a higher value than autonomy, exercising autonomy without respecting the right to life would become a serious moral and social problem. Likewise, euthanasia supporters some-times claim a 'right to live with dignity', which must be understood as a personal obligation, referred more to the ethical than to the strictly legal sphere. In countries where it is already legalized, euthanasia practice has extended to cases where it is not the patient who requests this but the family or some healthcare professional, or even the legal system-when they think that the patient is living in a condition which is not worthy to live. Generalization of euthanasia possibly will end in affecting those who need more care, such as elder, chronically ill or dying people, damaging severely personal basic rights. Nature, purpose and tradition of medicine rule out the practice of euthanasia, which ought not be considered a medical act or legitimately compulsory for physicians. Today's medicine counts with effective treatments for pain and suffering, such as palliative care, including sedative therapy, which best preserves persons dignity and keeps safe the ethos of the medical profession. PMID:22051717

2011-05-01

223

Therapy with proteolytic enzymes in rheumatic disorders.  

PubMed

Plant extracts with a high content of proteolytic enzymes have been used in traditional medicine for a long time. Besides herbal proteinases, 'modern' enzyme therapy includes pancreatic enzymes. The therapeutic use of proteolytic enzymes is empirically based, but is also supported by scientific studies. This review provides an overview of preclinical and clinical trials of systemic enzyme therapy in rheumatic disorders. Studies of the use of proteolytic enzymes in rheumatic disorders have mostly been carried out on enzyme preparations consisting of combinations of bromelain, papain, trypsin and chymotrypsin. The precise mechanism of action of systemic enzyme therapy remains unresolved. The ratio of proteinases to antiproteinases, which is affected by rheumatic diseases, appears to be influenced by the oral administration of proteolytic enzymes, probably via induction of the synthesis of antiproteinases or a signal transduction of the proteinase-antiproteinase complex via specific receptors. Furthermore, there are numerous alterations of cytokine composition during therapy with orally administered enzymes resulting from immunomodulatory effects, which might be an indication of the efficacy of enzyme therapy. The results of various studies (placebo-controlled and comparisons with nonsteroidal anti-inflammatory drugs) in patients with rheumatic diseases suggest that oral therapy with proteolytic enzymes produces certain analgesic and anti-inflammatory effects. However, the results are often inconsistent. Nevertheless, in the light of preclinical and experimental data as well as therapeutic experience, the application of enzyme therapy seems plausible in carefully chosen patients with rheumatic disorders. PMID:11784210

Leipner, J; Iten, F; Saller, R

2001-01-01

224

Improvements of biomass deconstruction enzymes  

SciTech Connect

Sandia National Laboratories and DSM Innovation, Inc. collaborated on the investigation of the structure and function of cellulases from thermophilic fungi. Sandia's role was to use its expertise in protein structure determination and X-ray crystallography to solve the structure of these enzymes in their native state and in their substrate and product bound states. Sandia was also tasked to work with DSM to use the newly solved structure to, using computational approaches, analyze enzyme interactions with both bound substrate and bound product; the goal being to develop approaches for rationally designing improved cellulases for biomass deconstruction. We solved the structures of five cellulases from thermophilic fungi. Several of these were also solved with bound substrate/product, which allowed us to predict mutations that might enhance activity and stability.

Sale, K. L.

2012-03-01

225

Enzyme dynamics from NMR spectroscopy.  

PubMed

Conspectus Biological activities of enzymes, including regulation or coordination of mechanistic stages preceding or following the chemical step, may depend upon kinetic or equilibrium changes in protein conformations. Exchange of more open or flexible conformational states with more closed or constrained states can influence inhibition, allosteric regulation, substrate recognition, formation of the Michaelis complex, side reactions, and product release. NMR spectroscopy has long been applied to the study of conformational dynamic processes in enzymes because these phenomena can be characterized over multiple time scales with atomic site resolution. Laboratory-frame spin-relaxation measurements, sensitive to reorientational motions on picosecond-nanosecond time scales, and rotating-frame relaxation-dispersion measurements, sensitive to chemical exchange processes on microsecond-millisecond time scales, provide information on both conformational distributions and kinetics. This Account reviews NMR spin relaxation studies of the enzymes ribonuclease HI from mesophilic (Escherichia coli) and thermophilic (Thermus thermophilus) bacteria, E. coli AlkB, and Saccharomyces cerevisiae triosephosphate isomerase to illustrate the contributions of conformational flexibility and dynamics to diverse steps in enzyme mechanism. Spin relaxation measurements and molecular dynamics (MD) simulations of the bacterial ribonuclease H enzymes show that the handle region, one of three loop regions that interact with substrates, interconverts between two conformations. Comparison of these conformations with the structure of the complex between Homo sapiens ribonuclease H and a DNA:RNA substrate suggests that the more closed state is inhibitory to binding. The large population of the closed conformation in T. thermophilus ribonuclease H contributes to the increased Michaelis constant compared with the E. coli enzyme. NMR spin relaxation and fluorescence spectroscopy have characterized a conformational transition in AlkB between an open state, in which the side chains of methionine residues in the active site are disordered, and a closed state, in which these residues are ordered. The open state is highly populated in the AlkB/Zn(II) complex, and the closed state is highly populated in the AlkB/Zn(II)/2OG/substrate complex, in which 2OG is the 2-oxoglutarate cosubstrate and the substrate is a methylated DNA oligonucleotide. The equilibrium is shifted to approximately equal populations of the two conformations in the AlkB/Zn(II)/2OG complex. The conformational shift induced by 2OG ensures that 2OG binds to AlkB/Zn(II) prior to the substrate. In addition, the opening rate of the closed conformation limits premature release of substrate, preventing generation of toxic side products by reaction with water. Closure of active site loop 6 in triosephosphate isomerase is critical for forming the Michaelis complex, but reopening of the loop after the reaction is (partially) rate limiting. NMR spin relaxation and MD simulations of triosephosphate isomerase in complex with glycerol 3-phosphate demonstrate that closure of loop 6 is a highly correlated rigid-body motion. The MD simulations also indicate that motions of Gly173 in the most flexible region of loop 6 contribute to opening of the active site loop for product release. Considered together, these three enzyme systems illustrate the power of NMR spin relaxation investigations in providing global insights into the role of conformational dynamic processes in the mechanisms of enzymes from initial activation to final product release. PMID:25574774

Palmer, Arthur G

2015-02-17

226

Metrological aspects of enzyme production  

NASA Astrophysics Data System (ADS)

Enzymes are frequently used in biotechnology to carry out specific biological reactions, either in industrial processes or for the production of bioproducts and drugs. Microbial lipases are an important group of biotechnologically valuable enzymes that present widely diversified applications. Lipase production by microorganisms is described in several published papers; however, none of them refer to metrological evaluation and the estimation of the uncertainty in measurement. Moreover, few of them refer to process optimization through experimental design. The objectives of this work were to enhance lipase production in shaken-flasks with Yarrowia lipolytica cells employing experimental design and to evaluate the uncertainty in measurement of lipase activity. The highest lipolytic activity obtained was about three- and fivefold higher than the reported activities of CRMs BCR-693 and BCR-694, respectively. Lipase production by Y. lipolytica cells aiming the classification as certified reference material is recommended after further purification and stability studies.

Kerber, T. M.; Dellamora-Ortiz, G. M.; Pereira-Meirelles, F. V.

2010-05-01

227

Flavonoid Evolution: An Enzymic Approach  

PubMed Central

Flavonoid evolution in land plants is discussed from an enzymic point of view, based on the present day distribution of the major subgroups of flavonoids in bryophytes, lower and higher vascular plants. The importance of varied functions in the origin of pathways with a series of sequential steps leading to end-products is considered; it is argued that the initial function is that of an internal regulatory agent, rather than as a filter against ultraviolet irradiation. The basic synthases, hydroxylases, and reductases of flavonoid pathways are presumed to have evolved from enzymes of primary metabolism. A speculative scheme is presented of flavonoid evolution within a primitive group of algae derived from a Charophycean rather than a Chlorophycean line, as a land environment was invaded. Flavonoid evolution was preceded by that of the phenylpropanoid and malonyl-coenzyme A pathways, but evolved prior to the lignin pathway. PMID:16668242

Stafford, Helen A.

1991-01-01

228

BIOCHEMISTRY: An Enzyme Assembly Line  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Fatty acid synthases and related megaenzymes are highly adaptable to new functions as a result of their modular architecture. The fundamental polymers of biology--proteins, DNA, and RNA--are products of repetitive condensation of simple amino acid or nucleotide building blocks and are comparatively easy to assemble. However, other biomolecules require additional reactions beyond condensation of building blocks. Examples are the fatty acids and the polyketide and nonribosomal peptide secondary metabolites. These molecules are produced by complex enzyme assembly lines that include multiple catalytic domains. Two new crystal structures--one reported recently (1), the other by Maier et al. on page 1315 of this issue (2)--enrich our understanding of how these mega-enzymes function as efficient factories to produce a remarkable range of metabolic products.

Janet L. Smith (University of Michigan; Life Sciences Institute; Department of Biological Chemistry)

2008-09-05

229

A DNA enzyme with Mg(2+)-Dependent RNA Phosphoesterase Activity  

NASA Technical Reports Server (NTRS)

Previously we demonstrated that DNA can act as an enzyme in the Pb(2+)-dependent cleavage of an RNA phosphoester. This is a facile reaction, with an uncatalyzed rate for a typical RNA phosphoester of approx. 10(exp -4)/ min in the presence of 1 mM Pb(OAc)2 at pH 7.0 and 23 C. The Mg(2+) - dependent reaction is more difficult, with an uncatalyzed rate of approx. 10(exp -7)/ min under comparable conditions. Mg(2+) - dependent cleavage has special relevance to biology because it is compatible with intracellular conditions. Using in vitro selection, we sought to develop a family of phosphoester-cleaving DNA enzymes that operate in the presence of various divalent metals, focusing particularly on the Mg(2+) - dependent reaction. Results: We generated a population of greater than 10(exp 13) DNAs containing 40 random nucleotides and carried out repeated rounds of selective amplification, enriching for molecules that cleave a target RNA phosphoester in the presence of 1 mM Mg(2+), Mn(2+), Zn(2+) or Pb(2+). Examination of individual clones from the Mg(2+) lineage after the sixth round revealed a catalytic motif comprised of a three-stem junction.This motif was partially randomized and subjected to seven additional rounds of selective amplification, yielding catalysts with a rate of 0.01/ min. The optimized DNA catalyst was divided into separate substrate and enzyme domains and shown to have a similar level of activity under multiple turnover conditions. Conclusions: We have generated a Mg(2+) - dependent DNA enzyme that cleaves a target RNA phosphoester with a catalytic rate approx. 10(exp 5) - fold greater than that of the uncatalyzed reaction. This activity is compatible with intracellular conditions, raising the possibility that DNA enzymes might be made to operate in vivo.

Breaker, Ronald R.; Joyce, Gerald F.

1995-01-01

230

Enzymes involved in the biodegradation of hexachlorocyclohexane: a mini review.  

PubMed

The scope of this paper encompasses the following subjects: (i) aerobic and anaerobic degradation pathways of ?-hexachlorocyclohexane (HCH); (ii) important genes and enzymes involved in the metabolic pathways of ?-HCH degradation; (iii) the instrumental methods for identifying and quantifying intermediate metabolites, such as gas chromatography coupled to mass spectrometry (GC-MS) and other techniques. It can be concluded that typical anaerobic and aerobic pathways of ?-HCH are well known for a few selected microbial strains, although less is known for anaerobic consortia where the possibility of synergism, antagonism, and mutualism can lead to more particular routes and more effective degradation of ?-HCH. Conversion and removals in the range 39%-100% and 47%-100% have been reported for aerobic and anaerobic cultures, respectively. Most common metabolites reported for aerobic degradation of lindane are ?-pentachlorocyclohexene (?-PCCH), 2,5-dichlorobenzoquinone (DCBQ), Chlorohydroquinone (CHQ), chlorophenol, and phenol, whereas PCCH, isomers of trichlorobenzene (TCB), chlorobenzene, and benzene are the most typical metabolites found in anaerobic pathways. Enzyme and genetic characterization of the involved molecular mechanisms are in their early infancy; more work is needed to elucidate them in the future. Advances have been made on identification of enzymes of Sphingomonas paucimobilis where the gene LinB codifies for the enzyme haloalkane dehalogenase that acts on 1,3,4,6-tetrachloro 1,4-cyclohexadiene, thus debottlenecking the pathway. Other more common enzymes such as phenol hydroxylase, catechol 1,2-dioxygenase, catechol 2,3-dioxygenase are also involved since they attack intermediate metabolites of lindane such as catechol and less substituted chlorophenols. Chromatography coupled to mass spectrometric detector, especially GC-MS, is the most used technique for resolving for ?-HCH metabolites, although there is an increased participation of HPLC-MS methods. Scintillation methods are very useful to assess final degradation of ?-HCH. PMID:21992990

Camacho-Pérez, Beni; Ríos-Leal, Elvira; Rinderknecht-Seijas, Noemí; Poggi-Varaldo, Héctor M

2012-03-01

231

Weak Lignin-Binding Enzymes  

Microsoft Academic Search

Economic barriers preventing commercialization of lignocellulose-toethanol bioconversion processes include the high cost of\\u000a hydrolytic enzymes. One strategy for cost reduction is to improve the specific activities of cellulases by genetic engineering.\\u000a However, screening for improved activity typically uses “ideal” cellulosic substrates, and results are not necessarily applicable\\u000a to more realistic substrates such as pretreated hardwoods and softwoods. For lignocellulosic substrates,

ALEX BERLINp; Neil Gilkes; Arwa Kurabi; Renata Bura; Maobing Tu; Douglas Kilburn; John Saddler

232

Weak lignin-binding enzymes  

Microsoft Academic Search

Economic barriers preventing commercialization of lignocellulose-to-ethanol bioconversion processes include the high cost\\u000a of hydrolytic enzymes. One strategy for cost reduction is to improve the specific activities of cellulases by genetic engineering.\\u000a However, screening for improved activity typically uses “ideal” cellulosic substrates, and results are not necessarily applicable\\u000a to more realistic substrates such as pretreated hardwoods and softwoods. For lignocellulosic substrates,

Alex Berlin; Neil Gilkes; Arwa Kurabi; Renata Bura; Maobing Tu; Douglas Kilburn; John Saddler

2005-01-01

233

Mechanisms for regulating deubiquitinating enzymes  

PubMed Central

Ubiquitination is a reversible post-translational modification that plays a dynamic role in regulating most eukaryotic processes. Deubiquitinating enzymes (DUBs), which hydrolyze the isopeptide or peptide linkages joining ubiquitin to substrate lysines or N-termini, therefore play a key role in ubiquitin signaling. Cells employ multiple mechanisms to regulate DUB activity and thus ensure the appropriate biological response. Recent structural studies have shed light on several different mechanisms by which DUB activity and specificity is regulated. PMID:24403057

Wolberger, Cynthia

2014-01-01

234

Enzyme mediated resolution of alcohols  

Microsoft Academic Search

The racemic cis and trans isomers 1a and 1b of 2-(4-methoxybenzyl)-1-cyclohexanol were subjects of an enzyme mediated resolution via esterification in organic solvents, in which the chiral esters 2a and 2b of the corresponding alcohols 4a and 4b, and the chiral alcohols 3a and 3b were obtained. The chemical yield and enantioselectivity of this enzymatic reaction have been found to

Marie Zarevúcka; Martin Rejzek; Milan Pavlík; Zden?k Wimmer; Jan Zima; Marie-Dominique Legoy

1994-01-01

235

Malolactic enzyme from Oenococcus oeni  

PubMed Central

Malolactic enzymes (MLE) are known to directly convert L-malic acid into L-lactic acid with a catalytical requirement of nicotinamide adenine dinucleotide (NAD+) and Mn2+; however, the reaction mechanism is still unclear. To study a MLE, the structural gene from Oenococcus oeni strain DSM 20255 was heterologously expressed in Escherichia coli, yielding 22.9 kU l?1 fermentation broth. After affinity chromatography and removal of apparently inactive protein by precipitation, purified recombinant MLE had a specific activity of 280 U mg?1 protein with a recovery of approximately 61%. The enzyme appears to be a homodimer with a molecular mass of 128 kDa consisting of two 64 kDa subunits. Characterization of the recombinant enzyme showed optimum activity at pH 6.0 and 45°C, and Km, Vmax and kcat values of 4.9 mM, 427 U mg?1 and 456 sec?1 for L-malic acid, 91.4 µM, 295 U mg?1 and 315 sec?1 for NAD+ and 4.6 µM, 229 U mg?1 and 244 sec?1 for Mn2+, respectively. The recombinant MLE retained 95% of its activity after 3 mo at room temperature and 7 mo at 4°C. When using pyruvic acid as substrate, the enzyme showed the conversion of pyruvic acid with detectable L-lactate dehydrogenase (L-LDH) activity and oxidation of NADH. This interesting observation might explain that MLE catalyzes a redox reaction and hence, the requirements for NAD+ and Mn2+ during the conversion of L-malic to L-lactic acid. PMID:23196745

Schümann, Christina; Michlmayr, Herbert; del Hierro, Andrés M.; Kulbe, Klaus D.; Jiranek, Vladimir; Eder, Reinhard; Nguyen, Thu-Ha

2013-01-01

236

24 CFR 570.614 - Architectural Barriers Act and the Americans with Disabilities Act.  

Code of Federal Regulations, 2012 CFR

...Barriers Act and the Americans with Disabilities Act. 570.614 Section...Barriers Act and the Americans with Disabilities Act. (a) The Architectural...buildings). (b) The Americans with Disabilities Act (42 U.S.C....

2012-04-01

237

24 CFR 570.614 - Architectural Barriers Act and the Americans with Disabilities Act.  

Code of Federal Regulations, 2013 CFR

...Barriers Act and the Americans with Disabilities Act. 570.614 Section...Barriers Act and the Americans with Disabilities Act. (a) The Architectural...buildings). (b) The Americans with Disabilities Act (42 U.S.C....

2013-04-01

238

24 CFR 570.614 - Architectural Barriers Act and the Americans with Disabilities Act.  

Code of Federal Regulations, 2014 CFR

...Barriers Act and the Americans with Disabilities Act. 570.614 Section...Barriers Act and the Americans with Disabilities Act. (a) The Architectural...buildings). (b) The Americans with Disabilities Act (42 U.S.C....

2014-04-01

239

45 CFR 2543.86 - Clean Air Act and the Federal Water Pollution Control Act.  

Code of Federal Regulations, 2014 CFR

...Clean Air Act and the Federal Water Pollution Control Act. 2543.86 Section...Clean Air Act and the Federal Water Pollution Control Act. Contracts...et seq. ) and the Federal Water Pollution Control Act as amended (33...

2014-10-01

240

45 CFR 2543.86 - Clean Air Act and the Federal Water Pollution Control Act.  

Code of Federal Regulations, 2013 CFR

...Clean Air Act and the Federal Water Pollution Control Act. 2543.86 Section...Clean Air Act and the Federal Water Pollution Control Act. Contracts...et seq. ) and the Federal Water Pollution Control Act as amended (33...

2013-10-01

241

45 CFR 2543.86 - Clean Air Act and the Federal Water Pollution Control Act.  

Code of Federal Regulations, 2012 CFR

...Clean Air Act and the Federal Water Pollution Control Act. 2543.86 Section...Clean Air Act and the Federal Water Pollution Control Act. Contracts and...et seq.) and the Federal Water Pollution Control Act as amended (33...

2012-10-01

242

45 CFR 2543.86 - Clean Air Act and the Federal Water Pollution Control Act.  

Code of Federal Regulations, 2010 CFR

...Clean Air Act and the Federal Water Pollution Control Act. 2543.86 Section...Clean Air Act and the Federal Water Pollution Control Act. Contracts and...et seq.) and the Federal Water Pollution Control Act as amended (33...

2010-10-01

243

45 CFR 2543.86 - Clean Air Act and the Federal Water Pollution Control Act.  

Code of Federal Regulations, 2011 CFR

...Clean Air Act and the Federal Water Pollution Control Act. 2543.86 Section...Clean Air Act and the Federal Water Pollution Control Act. Contracts and...et seq.) and the Federal Water Pollution Control Act as amended (33...

2011-10-01

244

Immobilised enzymes in biorenewables production.  

PubMed

Oils, fats, carbohydrates, lignin, and amino acids are all important raw materials for the production of biorenewables. These compounds already play an important role in everyday life in the form of wood, fabrics, starch, paper and rubber. Enzymatic reactions do, in principle, allow the transformation of these raw materials into biorenewables under mild and sustainable conditions. There are a few examples of processes using immobilised enzymes that are already applied on an industrial scale, such as the production of High-Fructose Corn Syrup, but these are still rather rare. Fortunately, there is a rapid expansion in the research efforts that try to improve this, driven by a combination of economic and ecological reasons. This review focusses on those efforts, by looking at attempts to use fatty acids, carbohydrates, proteins and lignin (and their building blocks), as substrates in the synthesis of biorenewables using immobilised enzymes. Therefore, many examples (390 references) from the recent literature are discussed, in which we look both at the specific reactions as well as to the methods of immobilisation of the enzymes, as the latter are shown to be a crucial factor with respect to stability and reuse. The applications of the renewables produced in this way range from building blocks for the pharmaceutical and polymer industry, transport fuels, to additives for the food industry. A critical evaluation of the relevant factors that need to be improved for large-scale use of these examples is presented in the outlook of this review. PMID:23519171

Franssen, Maurice C R; Steunenberg, Peter; Scott, Elinor L; Zuilhof, Han; Sanders, Johan P M

2013-08-01

245

PETROLEUM INDUSTRY INFORMATION REPORTING ACT  

E-print Network

CALIFORNIA ENERGY COMMISSION PETROLEUM INDUSTRY INFORMATION REPORTING ACT: RULEMAKING;1 EXECUTIVE SUMMARY In the six months since the new Petroleum Industry Information Reporting Act (PIIRA which is used by the petroleum industry and market trading groups to assess the trends in California

246

Online Challenge versus Offline ACT  

ERIC Educational Resources Information Center

This article compares essays written in response to the ACT Essay prompt and a locally developed prompt used for placement. The two writing situations differ by time and genre: the ACT Essay is timed and argumentative; the locally developed is untimed and explanatory. The article analyzes the differences in student performance and predictive…

Peckham, Irvin

2010-01-01

247

Nurse Reinvestment Act. Public Law.  

ERIC Educational Resources Information Center

This document contains the text of the Nurse Reinvestment Act, which amends the Public Health Service Act to address the increasing shortage of registered nurses by instituting a series of policies to improve nurse recruitment and nurse retention. Title I details two initiatives to boost recruitment of nurses. The first initiative includes the…

Congress of the U.S., Washington, DC.

248

Education Leaders Applaud ATTAIN Act  

ERIC Educational Resources Information Center

This article talks about Achievement Through Technology and Innovation (ATTAIN) Act, a bill introduced by Senators Bingaman (D-NM), Burr (R-NC), and Murray (D-WA) and applauded by a coalition of education and industry groups. The proposed ATTAIN Act is similar to its companion in the House (HR 2449), and builds upon the Enhancing Education Through…

Curriculum Review, 2007

2007-01-01

249

Isocitrate Dehydrogenase Parameters of Enzyme Activity  

NSDL National Science Digital Library

One of four biology laboratories where students research the properties of a model enzyme, isocitrate dehydrogenase, by using scientifitic method, molecular biology enzyme assay techniques and data analysis using a computer graphing program.

John H. Williamson (Davidson College; )

1999-01-01

250

Extracellular enzyme kinetics scale with resource availability  

EPA Science Inventory

Microbial community metabolism relies on external digestion, mediated by extracellular enzymes that break down complex organic matter into molecules small enough for cells to assimilate. We analyzed the kinetics of 40 extracellular enzymes that mediate the degradation and assimi...

251

Crystallization studies of 5'-deoxyadenosyl radical enzymes  

E-print Network

Both adenosylcobalamin- and S-adenosylmethionine-dependent radical enzymes use a 5'-deoxyadenosyl radical intermediate to abstract a hydrogen atom from their substrates. In the case of adenosylcobalamin-dependent enzymes, ...

Phillips, Laura (Laura Anne)

2007-01-01

252

Operational uses of ACTS technology  

NASA Astrophysics Data System (ADS)

The NASA Advanced Communications Technology Satellite (ACTS) provides the technologies for very high gain hopping spot beam antennas, on-board baseband routing and processing, and wideband (1 GHz) Ka-band transponders. A number of studies have recently been completed using the experience gained in developing the actual ACTS system hardware to quantify how well the ACTS technology can be used in future operational systems. This paper provides a summary of these study results including the spacecraft (S/C) weight per unit circuit for providing services by ACTS technologies as compared to present-day satellites. The uses of the ACTS technology discussed are for providing T1 VSAT mesh networks, aeronautical mobile communications, supervisory control and data acquisition (SCADA) services, and high data rate networks for supercomputer and other applications.

Gedney, Richard T.; Wright, David L.; Balombin, Joseph L.; Sohn, Philip Y.; Cashman, William F.; Stern, Alan L.; Golding, Len; Palmer, Larry

1992-03-01

253

On a nonelementary progress curve equation and its application in enzyme kinetics.  

PubMed

The analytical equation describing progress curves of an enzyme catalyzed reaction acting upon the Michaelis-Menten mechanism has been known for the case in which only the free enzyme incurs a loss of its activity, either spontaneously or as a result of an irreversible inhibitor action. The solution of differential equations which defines the rates of enzyme inactivation and substrate utilization is expressed by a nonelementary function in equation of an implicit type that precludes direct calculation of the extent of reaction at any time. Previously, the implicit equations have been rearranged to the alternative formulas and solved by the Newton-Raphson method, but this procedure may fail when used upon the presented equation. For this reason the other root-finding numerical method was applied, and the enzyme kinetic parameters of such numerically solved implicit equation for the reaction mechanism of irreversibly inhibited acetylcholinesterase were fitted to the experimental data by a nonlinear regression computer program. PMID:11911683

Golicnik, Marko

2002-01-01

254

E2 enzyme inhibition by stabilization of a low affinity interface with ubiquitin  

PubMed Central

Weak protein interactions between ubiquitin and the ubiquitin-proteasome system (UPS) enzymes that mediate its covalent attachment to substrates serve to position ubiquitin for optimal catalytic transfer. We show that a small molecule inhibitor of the E2 ubiquitin conjugating enzyme Cdc34A, called CC0651, acts by trapping a weak interaction between ubiquitin and the E2 donor ubiquitin binding site. A structure of the ternary CC0651-Cdc34A-ubiquitin complex reveals that the inhibitor engages a composite binding pocket formed from Cdc34A and ubiquitin. CC0651 also suppresses the spontaneous hydrolysis rate of the Cdc34A-ubiquitin thioester, without overtly affecting the interaction between Cdc34A and the RING domain subunit of the E3 enzyme. Stabilization of the numerous other weak interactions between ubiquitin and UPS enzymes by small molecules may be a feasible strategy to selectively inhibit different UPS activities. PMID:24316736

St-Cyr, Daniel J.; Ziemba, Amy; Garg, Pankaj; Plamondon, Serge; Auer, Manfred; Sidhu, Sachdev; Marinier, Anne; Kleiger, Gary; Tyers, Mike; Sicheri, Frank

2014-01-01

255

Regeneration of Cofactors for Enzyme Biocatalysis  

E-print Network

Regeneration of Cofactors for Enzyme Biocatalysis Ryan D. Woodyer, Tyler W. Johannes and Huimin with the need for more selective, safer, and cleaner reactions. Enzymes as catalysts meet many of the needs-independent enzymes such as hydrolases, which perform relatively simple chemistry (Faber 2000). In contrast, cofactor

Zhao, Huimin

256

Better Enzymes for Biofuels and Green Chemistry  

E-print Network

Better Enzymes for Biofuels and Green Chemistry: Solving the Cofactor Imbalance Problem Imbalances-engineered the cofactor specificity of individual enzymes, this process has historically been arduous and prone to failure. Testing this procedure on a structurally and functionally diverse set of industrially relevant enzymes has

257

A Structural Perspective on Enzymes Activated by  

E-print Network

A Structural Perspective on Enzymes Activated by Monovalent Cations* Published, JBC Papers in Press and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110 Enzymes activated and catalysis. Recent progress in the structural biology of such enzymes has answered long standing questions

Di Cera, Enrico

258

Determining Enzyme Activity by Radial Diffusion  

ERIC Educational Resources Information Center

Discusses advantages of radial diffusion assay in determining presence of enzyme and/or rough approximation of amount of enzyme activities. Procedures are included for the preparation of starch-agar plates, and the application and determination of enzyme. Techniques using plant materials (homogenates, tissues, ungerminated embryos, and seedlings)…

Davis, Bill D.

1977-01-01

259

Enzyme Replacement Therapy in Feline Mucopolysaccharidosis I  

Microsoft Academic Search

Enzyme replacement therapy (ERT) has long been considered an approach to treating lysosomal storage disorders caused by deficiency of lysosomal enzymes. ERT is currently used to treat Gaucher disease and is being developed for several lysosomal storage disorders now that recombinant sources of the enzymes have become available. We have continued development of ERT for mucopolysaccharidosis I (MPS I) using

E. D. Kakkis; E. Schuchman; X. He; Q. Wan; S. Kania; S. Wiemelt; C. W. Hasson; T. O'Malley; M. A. Weil; G. A. Aguirre; D. E. Brown; M. E. Haskins

2001-01-01

260

Enzyme Mimic to Develop Antioxidant Nanoreactors: From Synthesis to Application  

E-print Network

Enzyme Mimic to Develop Antioxidant Nanoreactors: From Synthesis to Application.................................................................................................................20 1.10.1. Administration of antioxidant enzymes................................................................................20 1.10. 2. Administration of enzyme mimics

Amrhein, Valentin

261

Enzyme catalysis Enzyme catalysis is the catalysis of chemical reactions by  

E-print Network

Enzyme catalysis Enzyme catalysis is the catalysis of chemical reactions by specialized proteins known as enzymes. Catalysis of biochemical reactions in the cell is vital due to the very low reaction rates of the uncatalysed reactions. The mechanism of enzyme catalysis is similar in principle to other

Cavanagh, John

262

Porous silicon as the carrier matrix in microstructured enzyme reactors yielding high enzyme activities  

Microsoft Academic Search

Miniaturization and silicon integration of micro enzyme reactors for applications in micro total analysis systems (TASs) require new methods to achieve structures with a large surface area onto which the enzyme can be coupled. This paper describes a method to accomplish a highly efficient silicon microstructured enzyme reactor utilizing porous silicon as the carrier matrix. The enzyme activity of microreactors

J Drottyx; K. Lindström; L. Rosengren; T. Laurell

1997-01-01

263

Properties of yeast debranching enzyme and its specificity toward branched cyclodextrins.  

PubMed

Debranching enzyme was purified from Saccharomyces cerevisiae by DEAE-cellulose, omega-aminobutyl agarose and hydroxyapatite column chromatography. The activity of the eluent was monitored by the iodine-staining method which detects both the direct and indirect debranching enzymes. The elution profiles at every step showed a single peak with no shoulder. The crude and the purified enzyme preparations gave a single activity band with the same mobility on PAGE. The crude product produced 80% glucose compared to reducing sugar from glycogen-phosphorylase-limited dextrin while the partially purified and purified preparations produced 100% glucose. The activity of the purified enzyme was characterized and compared with that of the rabbit muscle enzyme by using various branched cyclodextrins as substrates. Both enzymes hydrolyzed 6-O-alpha-D-glucosyl cyclodextrins to glucose and cyclodextrins, but did not act on 6-O-alpha-maltosyl cyclomaltoheptaose. The yeast enzyme gave rise to glucose as a sole reducing sugar from 6-O-alpha-maltotriosyl cyclomaltoheptaose and 6-O-alpha-maltotetraosyl cyclomaltoheptaose, indicating that maltosyl and maltotriosyl transfers, respectively, had occurred, prior to the action of amylo-1,6-glucosidase. 6-O-alpha-D-Glucosyl cyclomaltoheptaose and 6-O-alpha-D-glucosyl cyclomalto-octaose, respectively, were better substrates than glycogen-phosphorylase-limited dextrin for the yeast and muscle enzymes. The yeast enzyme released glucose at a similar rate from 6-O-alpha-maltotriosyl cyclomaltoheptaose as from 6-O-alpha-maltotetraosyl cyclomaltoheptaose, but considerably lower rates than that from limit dextrin. The yeast debranching enzyme appears to be exclusively oligo-1,4----1,4-glucantransferase-amylo-1,6-glucosidase and does not have isoamylase. PMID:1597178

Tabata, S; Hizukuri, S

1992-06-01

264

BRENDA: The Comprehensive Enzyme Information System  

NSDL National Science Digital Library

BRENDA is a comprehensive database of enzymes maintained by the Institute of Biochemistry at the University of Cologne. Scientists collect and evaluate enzyme function data from primary literature sources. The site has recently been updated with new enzymes and an entirely new search engine. Various searches can be performed, including enzyme name, organism, or EC number. Links to literature citations, two dimensional images, and other databases are included for many of the enzymes. Academic and nonprofit use is free; commercial users must acquire a license.

265

Finding Sequences for over 270 Orphan Enzymes  

PubMed Central

Despite advances in sequencing technology, there are still significant numbers of well-characterized enzymatic activities for which there are no known associated sequences. These ‘orphan enzymes’ represent glaring holes in our biological understanding, and it is a top priority to reunite them with their coding sequences. Here we report a methodology for resolving orphan enzymes through a combination of database search and literature review. Using this method we were able to reconnect over 270 orphan enzymes with their corresponding sequence. This success points toward how we can systematically eliminate the remaining orphan enzymes and prevent the introduction of future orphan enzymes. PMID:24826896

Shearer, Alexander G.; Altman, Tomer; Rhee, Christine D.

2014-01-01

266

RecBCD Enzyme and the Repair of Double-Stranded DNA Breaks  

PubMed Central

Summary: The RecBCD enzyme of Escherichia coli is a helicase-nuclease that initiates the repair of double-stranded DNA breaks by homologous recombination. It also degrades linear double-stranded DNA, protecting the bacteria from phages and extraneous chromosomal DNA. The RecBCD enzyme is, however, regulated by a cis-acting DNA sequence known as Chi (crossover hotspot instigator) that activates its recombination-promoting functions. Interaction with Chi causes an attenuation of the RecBCD enzyme's vigorous nuclease activity, switches the polarity of the attenuated nuclease activity to the 5? strand, changes the operation of its motor subunits, and instructs the enzyme to begin loading the RecA protein onto the resultant Chi-containing single-stranded DNA. This enzyme is a prototypical example of a molecular machine: the protein architecture incorporates several autonomous functional domains that interact with each other to produce a complex, sequence-regulated, DNA-processing machine. In this review, we discuss the biochemical mechanism of the RecBCD enzyme with particular emphasis on new developments relating to the enzyme's structure and DNA translocation mechanism. PMID:19052323

Dillingham, Mark S.; Kowalczykowski, Stephen C.

2008-01-01

267

Enzymes in cleaning products: an overview of toxicological properties and risk assessment/management.  

PubMed

Enzymes used in cleaning products have an excellent safety profile, with little ability to cause adverse responses in humans. For acute toxicity, genotoxicity, sub-acute and repeated dose toxicity, enzymes are unremarkable. Reproductive toxicity and carcinogenicity are also not endpoints of concern. Exceptions are the ability of some proteases to produce irritating effects at high concentrations and more importantly, the intrinsic potential of these bacterial/fungal proteins to act as respiratory sensitizers. It is a reasonable assumption that the majority of enzyme proteins possess this hazard. However, methods for characterising the respiratory sensitisation hazard of enzymes are lacking and the information required for risk assessment and risk management, although sufficient, remains limited. Previously, most data was generated in animal models and in in vitro immunoassays that assess immunological cross-reactivity. Nevertheless, by the establishment of strict limits on airborne exposure (based on a defined minimal effect limit of 60ng active enzyme protein/m(3)) and air and health monitoring, occupational safety can be assured. Similarly, by ensuring that airborne exposure is kept similarly low, coupled with knowledge of the fate of these enzymes on skin and fabrics, it has proven possible to establish a long history of safe consumer use of enzyme containing products. PMID:22743221

Basketter, David; Berg, Ninna; Broekhuizen, Cees; Fieldsend, Mark; Kirkwood, Sheila; Kluin, Cornelia; Mathieu, Sophie; Rodriguez, Carlos

2012-10-01

268

3D imaging of enzymes working in situ.  

PubMed

Today, development of slowly digestible food with positive health impact and production of biofuels is a matter of intense research. The latter is achieved via enzymatic hydrolysis of starch or biomass such as lignocellulose. Free label imaging, using UV autofluorescence, provides a great tool to follow one single enzyme when acting on a non-UV-fluorescent substrate. In this article, we report synchrotron DUV fluorescence in 3-dimensional imaging to visualize in situ the diffusion of enzymes on solid substrate. The degradation pathway of single starch granules by two amylases optimized for biofuel production and industrial starch hydrolysis was followed by tryptophan autofluorescence (excitation at 280 nm, emission filter at 350 nm). The new setup has been specially designed and developed for a 3D representation of the enzyme-substrate interaction during hydrolysis. Thus, this tool is particularly effective for improving knowledge and understanding of enzymatic hydrolysis of solid substrates such as starch and lignocellulosic biomass. It could open up the way to new routes in the field of green chemistry and sustainable development, that is, in biotechnology, biorefining, or biofuels. PMID:24796213

Jamme, F; Bourquin, D; Tawil, G; Viksř-Nielsen, A; Buléon, A; Réfrégiers, M

2014-06-01

269

Enzyme specificity in galactomannan biosynthesis  

Microsoft Academic Search

Membrane-bound enzymes from developing legume-seed endosperms catalyse galactomannan biosynthesis in vitro from GDP-mannose and UDP-galactose. A mannosyltransferase [mannan synthase] catalyses the extension of the linear (1?4)-ß-linked d-mannan backbone towards the non-reducing end. A specific a-galactosyltransferase brings about the galactosyl-substitution of the backbone by catalysing the transfer of a (1?6)-a-d-galactosyl residue to an acceptor mannosyl residue at or close to the

J. S. Grant Reid; Mary Edwards; Michael J. Gidley; Allan H. Clark

1995-01-01

270

Sunshine Act:Physician financial transparency reports Beginning Aug. 1, 2013, the Physician Payments Sunshine Act (Sunshine Act), which  

E-print Network

Payments Sunshine Act (Sunshine Act), which is part of the Affordable Care Act, requires manufacturers outcomes. The congressional sponsors of the Affordable Care Act (ACA) reporting provisions have statedSunshine Act:Physician financial transparency reports Beginning Aug. 1, 2013, the Physician

Chapman, Michael S.

271

University College London: Enzyme Structures Database  

NSDL National Science Digital Library

This website features the Enzyme Structures Database, created by researchers Roman Laskowski and Andrew Wallace of the University College London. The database "contains the known enzyme structures that have been deposited in the Brookhaven Protein Data Bank (the PDB)." As of March 2003 the Brookhaven Protein Data Bank contained 10208 PDB-enzyme entries "involving 9873 separate PDB files - some files having more than one E.C. number associated with them. The enzyme structures are classified by their E.C. number (using the Mar 2003 v.30.0 release of the ENZYME Data Bank)." There are six classified groups of enzyme structures including Oxidoreductases, Transferases, and Hydrolases. This site also links to the PDBsum database which provides users an alternate means of accessing enzyme structures.

Laskowski, Roman

272

ENZYME PATTERNS OF THE ORGANS OF THE GOOSE EFFECTS OF FATTENING ON LIVER ENZYMES  

E-print Network

ENZYME PATTERNS OF THE ORGANS OF THE GOOSE EFFECTS OF FATTENING ON LIVER ENZYMES J.P. BRAUN1 A Marsan, France. RĂ©sumĂ© DISTRIBUTION DES ENZYMES DANS LES ORGANES DE L'OIE. EFFETS DE L'ENGRAISSEMENT SUR LES ENZYMES HĂ?PATIQUES. ― La distribution de quelques enzymes dans les organes de l'oie a Ă©tĂ©

Paris-Sud XI, Université de

273

Characterisation of three starch degrading enzymes: thermostable ?-amylase, maltotetraogenic and maltogenic ?-amylases.  

PubMed

Maltogenic ?-amylase from Bacillus stearothermophilus (BStA) is widely used as bread crumb anti-firming enzyme. A maltotetraose-forming ?-amylase from Pseudomonas saccharophila (PSA) was recently proposed as alternative, hence the need to compare both exo-acting enzymes with some endo-action component. A purely exo-acting thermostable ?-amylase from Clostridium thermosulfurogenes (CTB) was included for reference purposes. Under the experimental conditions used, temperature optima of the enzymes are rather similar (60-65 °C), but temperature stability decreased in the order BStA, PSA and CTB. The action of the enzymes on different substrates and their impact on the rheological behaviour of maize starch suspensions demonstrated that, while CTB acts exclusively through an exo-action mechanism, BStA displayed limited endo-action which became more pronounced at higher temperatures. PSA has more substantial endo-action than BStA, which is rather temperature independent. This is important for their impact in processes such as breadmaking, where temperature is gradually increased. PMID:22868150

Derde, L J; Gomand, S V; Courtin, C M; Delcour, J A

2012-11-15

274

Food Quality Protection Act (FQPA)  

NSDL National Science Digital Library

Brief summary of the Food Quality Protection Act concerning EPA regulation of pesticides. Links to FQPA Background, Tolerance Reassessment, Endocrine Disruptors, Science Policies, Implementation Status and Other Information Resources for FQPA.

275

SUPERFUND: GETTING INTO THE ACT  

EPA Science Inventory

This publication is intended to assist those interest in providing contractual services to the Superfund program. Superfund: Getting Into The Act" describes current Superfund contracts and provides contact points, addresses, and telephone numbers for firms with Superfund contract...

276

GOALS 2000: Educate America Act  

NSDL National Science Digital Library

GOALS 2000 Educate America Act was signed into law on March 31, 1994. Related documents are available at the Education Department online library including the full text, related fact sheets, and additional information.

277

[Preventing dangerous psychotic acting out].  

PubMed

Delusions of having been wronged, of persecution, of having a mission or order to execute, are frequently the causes of dangerous psychotic acting out. The regular clinical assessment of these patients and their treatment is essential for preventing this acting out, which can have dramatic consequences on the potential victims. If there is a treatment indication but refusal on the part of the patient to cooperate, it is necessary to resort to treatment without the patient's consent. PMID:25751909

Bouchard, Jean-Pierre

2015-01-01

278

On-Enzyme Refolding Permits Small RNA and tRNA Surveillance by the CCA-Adding Enzyme.  

PubMed

Transcription in eukaryotes produces a number of long noncoding RNAs (lncRNAs). Two of these, MALAT1 and Men?, generate a tRNA-like small RNA in addition to the mature lncRNA. The stability of these tRNA-like small RNAs and bona fide tRNAs is monitored by the CCA-adding enzyme. Whereas CCA is added to stable tRNAs and tRNA-like transcripts, a second CCA repeat is added to certain unstable transcripts to initiate their degradation. Here, we characterize how these two scenarios are distinguished. Following the first CCA addition cycle, nucleotide binding to the active site triggers a clockwise screw motion, producing torque on the RNA. This ejects stable RNAs, whereas unstable RNAs are refolded while bound to the enzyme and subjected to a second CCA catalytic cycle. Intriguingly, with the CCA-adding enzyme acting as a molecular vise, the RNAs proofread themselves through differential responses to its interrogation between stable and unstable substrates. PMID:25640237

Kuhn, Claus-D; Wilusz, Jeremy E; Zheng, Yuxuan; Beal, Peter A; Joshua-Tor, Leemor

2015-02-12

279

Microbial community composition shapes enzyme patterns in topsoil and subsoil horizons along a latitudinal transect in Western Siberia  

PubMed Central

Soil horizons below 30 cm depth contain about 60% of the organic carbon stored in soils. Although insight into the physical and chemical stabilization of soil organic matter (SOM) and into microbial community composition in these horizons is being gained, information on microbial functions of subsoil microbial communities and on associated microbially-mediated processes remains sparse. To identify possible controls on enzyme patterns, we correlated enzyme patterns with biotic and abiotic soil parameters, as well as with microbial community composition, estimated using phospholipid fatty acid profiles. Enzyme patterns (i.e. distance-matrixes calculated from these enzyme activities) were calculated from the activities of six extracellular enzymes (cellobiohydrolase, leucine-amino-peptidase, N-acetylglucosaminidase, chitotriosidase, phosphatase and phenoloxidase), which had been measured in soil samples from organic topsoil horizons, mineral topsoil horizons, and mineral subsoil horizons from seven ecosystems along a 1500 km latitudinal transect in Western Siberia. We found that hydrolytic enzyme activities decreased rapidly with depth, whereas oxidative enzyme activities in mineral horizons were as high as, or higher than in organic topsoil horizons. Enzyme patterns varied more strongly between ecosystems in mineral subsoil horizons than in organic topsoils. The enzyme patterns in topsoil horizons were correlated with SOM content (i.e., C and N content) and microbial community composition. In contrast, the enzyme patterns in mineral subsoil horizons were related to water content, soil pH and microbial community composition. The lack of correlation between enzyme patterns and SOM quantity in the mineral subsoils suggests that SOM chemistry, spatial separation or physical stabilization of SOM rather than SOM content might determine substrate availability for enzymatic breakdown. The correlation of microbial community composition and enzyme patterns in all horizons, suggests that microbial community composition shapes enzyme patterns and might act as a modifier for the usual dependency of decomposition rates on SOM content or C/N ratios. PMID:25859057

Schnecker, Jörg; Wild, Birgit; Takriti, Mounir; Eloy Alves, Ricardo J.; Gentsch, Norman; Gittel, Antje; Hofer, Angelika; Klaus, Karoline; Knoltsch, Anna; Lashchinskiy, Nikolay; Mikutta, Robert; Richter, Andreas

2015-01-01

280

Rennin Enzyme of Endothia parasitica  

PubMed Central

A microbiological screening program was instituted to search for an animal rennet substitute. Among 381 bacteria and 540 fungi tested, only one organism, Endothia parasitica, yielded a suitable enzyme substitute. The fungal rennin enzyme was crystallized and some of its properties were studied. It was found to be water-soluble, nondialyzable, precipitable with (NH4)2SO4 and organic solvents (e.g., acetone and isopropanol), and destroyed by heating for 5 min at 60 C. It was determined to be most stable in water at pH 4.5 and to have an isoelectric point of pH 5.5. On acid hydrolysis, it yielded: alanine, ammonia, arginine, aspartic acid, cysteic acid, cystine, glutamic acid, glycine, histidine, isoleucine, leucine, phenylalanine, proline, serine, threonine, tyrosine, and valine. No tryptophan was detected after alkaline hydrolysis. Its molecular weight was estimated to be in the range of 34,000 to 39,000. The milk-clotting activities of the fungal and animal rennins proved to be essentially identical in milk containing various concentrations of CaCl2. Both rennins manifested comparable clotting activities in milk at pH 6.0 to 7.0. Images Fig. 1 PMID:4868859

Sardinas, Joseph L.

1968-01-01

281

High-Throughput Enzyme Kinetics Using Microarrays  

SciTech Connect

We report a microanalytical method to study enzyme kinetics. The technique involves immobilizing horseradish peroxidase on a poly-L-lysine (PLL)- coated glass slide in a microarray format, followed by applying substrate solution onto the enzyme microarray. Enzyme molecules are immobilized on the PLL-coated glass slide through electrostatic interactions, and no further modification of the enzyme or glass slide is needed. In situ detection of the products generated on the enzyme spots is made possible by monitoring the light intensity of each spot using a scientific-grade charged-coupled device (CCD). Reactions of substrate solutions of various types and concentrations can be carried out sequentially on one enzyme microarray. To account for the loss of enzyme from washing in between runs, a standard substrate solution is used for calibration. Substantially reduced amounts of substrate solution are consumed for each reaction on each enzyme spot. The Michaelis constant K{sub m} obtained by using this method is comparable to the result for homogeneous solutions. Absorbance detection allows universal monitoring, and no chemical modification of the substrate is needed. High-throughput studies of native enzyme kinetics for multiple enzymes are therefore possible in a simple, rapid, and low-cost manner.

Guoxin Lu; Edward S. Yeung

2007-11-01

282

Enzyme-polymer based environmental monitors  

NASA Astrophysics Data System (ADS)

Enzymes are commonly used as the active element in chemical sensors because of their analyte specificity, sensitivity, and the speed with which they catalyze reactions. Their precision and reliability has them at the core of many FDAapproved medical diagnostic tests. Unfortunately, nature has evolved most enzymes to operate under a fairly narrow range of storage and operating conditions (i.e. pH, ionic strength, temperature, organic content, etc). The deployment of enzyme-based sensors in poorly controlled environments with fluctuating conditions can therefore be difficult. ICx Technologies has sought to minimize the impact of environmental parameters on enzyme catalysis through enzyme polymerization. Rather than being simply immobilized onto an existing substrate, enzymes are used as co-monomers with other conventional monomers in polymerization reactions. Enzymes are incorporated within the polymer through multiple covalent attachments. By essentially anchoring the enzyme's tertiary structure, the polymerization process reduces enzyme sensitivity to many environmental factors. ICx has built a number of chemical sensors using enzyme polymers, some of which continuously monitor air or water in real time. The developed sensors have proven to operate well in many different environments.

LeJeune, Keith; Berberich, Jason; Washburn, Jon; Erbeldinger, Markus; Sinclair, Jessica

2010-04-01

283

Enzyme nanoarchitectonics: organization and device application.  

PubMed

Fabrication of ultrasmall functional machines and their integration within ultrasmall areas or volumes can be useful for creation of novel technologies. The ultimate goal of the development of ultrasmall machines and device systems is to construct functional structures where independent molecules operate as independent device components. To realize exotic functions, use of enzymes in device structures is an attractive solution because enzymes can be regarded as efficient machines possessing high reaction efficiencies and specificities and can operate even under ambient conditions. In this review, recent developments in enzyme immobilization for advanced functions including device applications are summarized from the viewpoint of micro/nano-level structural control, or nanoarchitectonics. Examples are roughly classified as organic soft matter, inorganic soft materials or integrated/organized media. Soft matter such as polymers and their hybrids provide a medium appropriate for entrapment and encapsulation of enzymes. In addition, self-immobilization based on self-assembly and array formation results in enzyme nanoarchitectures with soft functions. For the confinement of enzymes in nanospaces, hard inorganic mesoporous materials containing well-defined channels play an important role. Enzymes that are confined exhibit improved stability and controllable arrangement, which are useful for formation of functional relays and for their integration into artificial devices. Layer-by-layer assemblies as well as organized lipid assemblies such as Langmuir-Blodgett films are some of the best media for architecting controllable enzyme arrangements. The ultrathin forms of these films facilitate their connection with external devices such as electrodes and transistors. Artificial enzymes and enzyme-mimicking catalysts are finally briefly described as examples of enzyme functions involving non-biological materials. These systems may compensate for the drawbacks of natural enzymes, such as their instabilities under harsh conditions. We believe that enzymes and their mimics will be freely coupled, organized and integrated upon demand in near future technologies. PMID:23348617

Ariga, Katsuhiko; Ji, Qingmin; Mori, Taizo; Naito, Masanobu; Yamauchi, Yusuke; Abe, Hideki; Hill, Jonathan P

2013-08-01

284

Self-assembled enzyme capsules in ionic liquid [BMIM][BF4] as templating nanoreactors for hollow silica nanocontainers.  

PubMed

Most of the self-assembly studies have hitherto explored the aqueous media as fluid phase for self-assembly of amphiphilic biomacromolecules, wherein architectural modification of biomolecules is generally a prerequisite for self-assembly of modified biomolecules. We demonstrate for the first time that ionic liquids can act as nonaqueous designer solvents to self-assemble amphiphilic biomacromolecules without requiring their prior modification. To this end, we show that enzyme (phytase) molecules self-assembled in the presence of an appropriate ionic liquid, resulting in the formation of enzyme capsules. Phytase capsules synthesized using this approach were further used as templating nanoreactors for the synthesis of enzyme-containing hollow silica nanocontainers. In situ immobilized phytase enzyme in the silica nanocontainers, when subjected to enzyme-reusability application, establishes them as excellent reusable biocatalysts. PMID:20860402

Soni, Sarvesh K; Ramanathan, Rajesh; Coloe, Peter J; Bansal, Vipul; Bhargava, Suresh K

2010-10-19

285

Tradeoff between enzyme and metabolite efficiency maintains metabolic homeostasis upon perturbations in enzyme capacity  

PubMed Central

What is the relationship between enzymes and metabolites, the two major constituents of metabolic networks? We propose three alternative relationships between enzyme capacity and metabolite concentration alterations based on a Michaelis–Menten kinetic; that is enzyme capacities, metabolite concentrations, or both could limit the metabolic reaction rates. These relationships imply different correlations between changes in enzyme capacity and metabolite concentration, which we tested by quantifying metabolite, transcript, and enzyme abundances upon local (single-enzyme modulation) and global (GCR2 transcription factor mutant) perturbations in Saccharomyces cerevisiae. Our results reveal an inverse relationship between fold-changes in substrate metabolites and their catalyzing enzymes. These data provide evidence for the hypothesis that reaction rates are jointly limited by enzyme capacity and metabolite concentration. Hence, alteration in one network constituent can be efficiently buffered by converse alterations in the other constituent, implying a passive mechanism to maintain metabolic homeostasis upon perturbations in enzyme capacity. PMID:20393576

Fendt, Sarah-Maria; Buescher, Joerg Martin; Rudroff, Florian; Picotti, Paola; Zamboni, Nicola; Sauer, Uwe

2010-01-01

286

3 CFR - The Endangered Species Act  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false The Endangered Species Act Presidential Documents...Memorandum of March 3, 2009 The Endangered Species Act Memorandum for the Heads...Departments and Agencies The Endangered Species Act (ESA), 16...

2010-01-01

287

7 CFR 989.2 - Act.  

Code of Federal Regulations, 2013 CFR

...MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN IN CALIFORNIA Order Regulating Handling Definitions § 989.2 Act. Act means Public Act No. 10,...

2013-01-01

288

Arbeidslivets lover Act relating to working environment,  

E-print Network

Arbeidslivets lover Act relating to working environment, working hours and employment protection, etc. (Working Environment Act). as subsequently amended, last by the Act of 14. December 2012 No. 80.notification................................................................... 6 Chapter 3. Working environment measures..................................... 6 Section.3

Johansen, Tom Henning

289

7 CFR 906.2 - Act.  

Code of Federal Regulations, 2014 CFR

...ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE ORANGES AND GRAPEFRUIT GROWN IN LOWER RIO GRANDE VALLEY IN TEXAS Order Regulating Handling Definitions § 906.2 Act. Act means Public Act No. 10, 73d Congress, as amended...

2014-01-01

290

7 CFR 945.2 - Act.  

Code of Federal Regulations, 2012 CFR

...and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE IRISH POTATOES GROWN IN CERTAIN DESIGNATED COUNTIES IN IDAHO, AND MALHEUR COUNTY, OREGON Order Regulating Handling Definitions § 945.2 Act. Act means Public Act No....

2012-01-01

291

7 CFR 945.2 - Act.  

Code of Federal Regulations, 2010 CFR

...and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE IRISH POTATOES GROWN IN CERTAIN DESIGNATED COUNTIES IN IDAHO, AND MALHEUR COUNTY, OREGON Order Regulating Handling Definitions § 945.2 Act. Act means Public Act No....

2010-01-01

292

Endangered Species Act Biennial Report to  

E-print Network

Endangered Species Act Biennial Report to Congress October 1, 1998 - September 30, 2000 Prepared by Fisheries Service Office of Protected Resources #12;Endangered Species Act Biennial Report to Congress Species Act Biennial Report to Congress Table of Contents Introduction

293

75 FR 30107 - Community Reinvestment Act Sunshine  

Federal Register 2010, 2011, 2012, 2013, 2014

...required by the Paperwork Reduction Act. Today, OTS is soliciting public...Proposal: Community Reinvestment Act Sunshine. OMB Number: 1550-0105...required under section 711 of the Gramm-Leach-Bliley Act, Public Law No. 106-102....

2010-05-28

294

75 FR 44852 - Community Reinvestment Act Sunshine  

Federal Register 2010, 2011, 2012, 2013, 2014

...required by the Paperwork Reduction Act of 1995. OTS is soliciting public...Proposal: Community Reinvestment Act Sunshine. OMB Number: 1550-0105...required under section 711 of the Gramm-Leach-Bliley Act, Public Law 106-102. This...

2010-07-29

295

7 CFR 930.1 - Act.  

Code of Federal Regulations, 2014 CFR

...OF AGRICULTURE TART CHERRIES GROWN IN THE STATES OF MICHIGAN, NEW YORK, PENNSYLVANIA, OREGON, UTAH, WASHINGTON, AND WISCONSIN Order Regulating Handling Definitions § 930.1 Act. Act means Public Act No. 10, 73d Congress (May...

2014-01-01

296

7 CFR 930.1 - Act.  

Code of Federal Regulations, 2011 CFR

...OF AGRICULTURE TART CHERRIES GROWN IN THE STATES OF MICHIGAN, NEW YORK, PENNSYLVANIA, OREGON, UTAH, WASHINGTON, AND WISCONSIN Order Regulating Handling Definitions § 930.1 Act. Act means Public Act No. 10, 73d Congress (May 12,...

2011-01-01

297

7 CFR 917.2 - Act.  

Code of Federal Regulations, 2010 CFR

...MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN CALIFORNIA Order Regulating Handling Definitions § 917.2 Act. Act means Public Act No. 10, 73d...

2010-01-01

298

7 CFR 1220.600 - Act.  

Code of Federal Regulations, 2010 CFR

...ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SOYBEAN PROMOTION, RESEARCH, AND CONSUMER INFORMATION Procedures...Referendum Definitions § 1220.600 Act. Act means the Soybean, Promotion, Research, and Consumer Information Act set...

2010-01-01

299

Ethanologenic Enzymes of Zymomonas mobilis  

SciTech Connect

Zymomonas mobilis is a unique microorganism in being both obligately fermentative and utilizing a Entner-Doudoroff pathway for glycolysis. Glycolytic flux in this organism is readily measured as evolved carbon dioxide, ethanol, or glucose consumed and exceeds 1 {micro}mole glucose/min per mg cell protein. To support this rapid glycolysis, approximately 50% of cytoplasmic protein is devoted to the 13 glycolytic and fermentative enzymes which constitute this central catabolic pathway. Only 1 ATP (net) is produced from each glucose metabolized. During the past grant period, we have completed the characterization of 11 of the 13 glycolytic genes from Z. mobilis together with complementary but separate DOE-fimded research by a former post-dot and collaborator, Dr. Tyrrell Conway. Research funded in my lab by DOE, Division of Energy Biosciences can be divided into three sections: A. Fundamental studies; B. Applied studies and utility; and C. Miscellaneous investigations.

Ingram, Lonnie O'Neal

1999-03-01

300

Sfericase, a novel proteolytic enzyme.  

PubMed

Sfericase, a novel protease produced by a strain of Bacillus sphaericus, has endopeptidase activity. Sfericase inhibits various experimental acute inflammations and reduces viscosity of sputum obtained from subacute bronchitic rabbits by oral treatment. A low molecular fraction of serum obtained from animals given oral sfericase also has an anti-inflammatory effect. This result suggests that a secondarily produced substance might play a role in the manifestation of anti-inflammatory action. The toxicity of sfericase is as low as that of other anti-inflammatory enzymes. Sfericase is detected in serum of animals given massive oral dosage, but not at clinical dosage. Clinical studies have been carried out in more than 900 patients. In double-blind studies with serratiopeptidase, sfericase is as useful as the reference drug. Sfericase has been proven effective in some chronic inflammations, such as chronic sinusitis and difficult expectoration associated with bronchopulmonary diseases. Moreover, it has less side effects. PMID:6354943

Yoshida, K

1983-09-01

301

Functionality of dielectrophoretically immobilized enzyme molecules.  

PubMed

The enzyme horseradish peroxidase has been immobilized on nanoelectrode arrays by alternating current dielectrophoresis (DEP). Preservation of its enzymatic function after field application was demonstrated by oxidizing dihydrorhodamine 123 with hydrogen peroxide as co-oxidant to create its fluorescent form, rhodamine 123 (Rh123). Localization of the fluorescently labeled enzyme and its product was conducted by fluorescence microscopy. Nanoelectrodes were prepared as tungsten pins arranged in square arrays. Experimental parameters for dielectrophoretic immobilization were optimized for even enzyme distribution and for enzymatic efficiency. Enzyme activity was quantified by determination of fluorescence intensities of immobilized enzyme molecules and of Rh123 produced. These results demonstrate that DEP can be applied to immobilize enzyme molecules while retaining their activity and rendering any chemical modifications unnecessary. This introduces a novel way for the preparation of bioactive surfaces for processes such as biosensing. PMID:24254805

Laux, Eva-Maria; Kaletta, Udo C; Bier, Frank F; Wenger, Christian; Hölzel, Ralph

2014-02-01

302

77 FR 5793 - Beaches Environmental Assessment and Coastal Health Act; Availability of BEACH Act Grants  

Federal Register 2010, 2011, 2012, 2013, 2014

...Health Act; Availability of BEACH Act Grants AGENCY: Environmental Protection Agency...program development and implementation grants to eligible states, territories, tribes...and tribes that have received BEACH Act grants in the past to apply for BEACH Act...

2012-02-06

303

Engineering Enzymes in Energy Crops: Conditionally Activated Enzymes Expressed in Cellulosic Energy Crops  

SciTech Connect

Broad Funding Opportunity Announcement Project: Enzymes are required to break plant biomass down into the fermentable sugars that are used to create biofuel. Currently, costly enzymes must be added to the biofuel production process. Engineering crops to already contain these enzymes will reduce costs and produce biomass that is more easily digested. In fact, enzyme costs alone account for $0.50-$0.75/gallon of the cost of a biomass-derived biofuel like ethanol. Agrivida is genetically engineering plants to contain high concentrations of enzymes that break down cell walls. These enzymes can be “switched on” after harvest so they won’t damage the plant while it’s growing.

None

2010-01-15

304

Carrier-free immobilized enzymes for biocatalysis  

Microsoft Academic Search

Methods for the preparation of carrier-free insoluble enzymes are reviewed. The technology of cross-linked enzyme aggregates\\u000a has now been applied to a range of synthetically useful activities. Fusion proteins are also gaining momentum because they\\u000a allow a relatively selective aggregation or even a specific self-assembly of the desired enzyme activity into insoluble particles\\u000a in the absence of potentially denaturing chemicals

Ulrich Roessl; Jozef Nahálka; Bernd Nidetzky

2010-01-01

305

Advanced development of immobilized enzyme reactors  

NASA Technical Reports Server (NTRS)

Fixed-bed reactors have been used at NASA-Marshall to purify wastewater generated by an end-use equipment facility, on the basis of a combination of multifiltration unibeds and enzyme unibeds. The enzyme beds were found to effectively remove such targeted organics as urea, alcohols, and aldehydes, down to levels lying below detection limits. The enzyme beds were also found to remove organic contaminants not specifically targeted.

Jolly, Clifford D.; Schussel, Leonard J.; Carter, Layne

1991-01-01

306

Industrial Applications of Lignin-Transforming Enzymes  

Microsoft Academic Search

Lignin-degrading and modifying enzymes are produced under specific culture conditions by white-rot fungi. Most of these enzymes are excreted into the extracellular environment and can be purified from culture supernatant. At RepliGen we have characterized many of the extracellular proteins from the white-rot fungus Phanerochaete chrysosporium. Industrial application potentials for these enzymes are predicted to be in the chemical industry,

Roberta L. Farrell

1987-01-01

307

Lignin-degrading enzyme from Phanerochaete chrysosporium  

Microsoft Academic Search

The extracellular fluid of ligninolytic cultures of the white-rot wooddestroying fungus,Phanerochaete chrysosporium Burds., contains an enzyme that degrades lignin model compounds as well as lignin itself (1). Like ligninolytic activity, the enzyme appears during idiophasic metabolism, which is triggered by nitrogen starvation.\\u000a The enzyme has been purified to homogeneity by DEAE-Biogel A chromatography, as assessed by SDS polyacrylamide gel electrophoresis,

T. K. Kirk; M. Tien

1984-01-01

308

HIPAA: Health Insurance Portability and Accountability Act  

MedlinePLUS

In this article HIPAA: Health Insurance Portability and Accountability Act This section helps explain the protections provided by the Health Insurance Portability and Accountability Act (HIPAA), an ...

309

7 CFR 1216.1 - Act.  

Code of Federal Regulations, 2014 CFR

...SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions § 1216.1 Act. Act...

2014-01-01

310

7 CFR 1216.1 - Act.  

Code of Federal Regulations, 2013 CFR

...SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions § 1216.1 Act. Act...

2013-01-01

311

7 CFR 1214.1 - Act.  

Code of Federal Regulations, 2013 CFR

...AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information Order Definitions § 1214.1 Act. Act...

2013-01-01

312

7 CFR 1214.1 - Act.  

Code of Federal Regulations, 2012 CFR

...AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information Order Definitions § 1214.1 Act. Act...

2012-01-01

313

7 CFR 1214.1 - Act.  

Code of Federal Regulations, 2014 CFR

...AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information Order Definitions § 1214.1 Act. Act...

2014-01-01

314

7 CFR 1221.1 - Act.  

Code of Federal Regulations, 2013 CFR

...MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.1 Act. Act...

2013-01-01

315

7 CFR 1221.1 - Act.  

Code of Federal Regulations, 2014 CFR

...MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.1 Act. Act...

2014-01-01

316

7 CFR 1221.1 - Act.  

Code of Federal Regulations, 2010 CFR

...MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.1 Act. Act...

2010-01-01

317

7 CFR 1221.1 - Act.  

Code of Federal Regulations, 2011 CFR

...MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.1 Act. Act...

2011-01-01

318

7 CFR 1221.1 - Act.  

Code of Federal Regulations, 2012 CFR

...MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.1 Act. Act...

2012-01-01

319

7 CFR 1220.101 - Act.  

Code of Federal Regulations, 2010 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE SOYBEAN PROMOTION, RESEARCH, AND CONSUMER INFORMATION Soybean Promotion and Research Order Definitions...101 Act. The term Act means the Soybean Promotion, Research, and Consumer...

2010-01-01

320

Nematicidal enzymes from microorganisms and their applications.  

PubMed

Microorganisms can attack and kill nematodes by diverse processes such as capturing, parasitizing, and producing toxins and enzymes. Extracellular enzymes, including serine proteases, chitinases, and collagenases are shown to be important virulence factors that can degrade the main chemical constituents of the nematode cuticle and eggshell. Here, we review the structure, function, regulation, and evolution of these nematicidal enzymes and provide insights into the mechanisms of microbial infections against nematodes. We discuss the practical applications of these nematicidal enzymes in agriculture and other areas. PMID:23832084

Yang, Jinkui; Liang, Lianming; Li, Juan; Zhang, Ke-Qin

2013-08-01

321

Relation between Enzymic Catalysis and Energy Coupling  

NASA Astrophysics Data System (ADS)

The principles that underlie enzyme catalysis also apply to energy coupling processes. A comparison is made between a kinase system that mediates the phosphorylation of glucose by ATP (hexokinase), as the prototype for enzymic catalysis, and the mitochondrial electron-transfer complexes, as the prototypes for energy coupling systems. Induced polarization of chemical bonds and charge separation and elimination are common component events of both enzyme catalysis and energy coupling. Thus, definite limits can be imposed on models of energy coupling; they must comply with the basic principles of enzymic catalysis.

Fry, Mitchell; Blondin, George A.; Green, David E.

1980-10-01

322

A cellular automata model of enzyme kinetics.  

PubMed

We have developed a cellular automata model of an enzyme reaction with a substrate in water. The model produces Michaelis-Menten kinetics with good Lineweaver-Burk plots. The variation in affinity parameters predicts that, in general, hydrophobic substrates are more reactive with enzymes, this attribute being more important than the relationship between enzyme and substrate. The ease of generation and the illustrative value of the model lead us to believe that cellular automata models have a useful role in the study of dynamic phenomena such as enzyme kinetics. PMID:9076636

Kier, L B; Cheng, C K; Testa, B; Carrupt, P A

1996-08-01

323

Get Your ACT Together: A Resource Guide for ACT Preparation.  

ERIC Educational Resources Information Center

This guide is designed as a resource for (1) Oklahoma teachers, counselors, and parents, to help them help their students prepare for the ACT assessment; and (2) students, to help dispel some common myths and misunderstandings as they prepare for the test. Section A, for administrators, teachers, counselors, Indian program staffs, and…

Oklahoma State Dept. of Education, Oklahoma City.

324

Nocardiopsis species as potential sources of diverse and novel extracellular enzymes.  

PubMed

Members of the genus Nocardiopsis are generally encountered in locations that are inherently extreme. They are present in frozen soils, desert sand, compost, saline or hypersaline habitats (marine systems, salterns and soils) and alkaline places (slag dumps, lake soils and sediments). In order to survive under these severe conditions, they produce novel and diverse enzymes that allow them to utilize the available nutrients and to thrive. The members of this genus are multifaceted and release an assortment of extracellular hydrolytic enzymes. They produce enzymes that are cold-adapted (?-amylases), thermotolerant (?-amylases and xylanases), thermoalkalotolerant (cellulases, ?-1,3-glucanases), alkali-tolerant thermostable (inulinases), acid-stable (keratinase) and alkalophilic (serine proteases). Some of the enzymes derived from Nocardiopsis species act on insoluble polymers such as glucans (pachyman and curdlan), keratin (feathers and prion proteins) and polyhydroxyalkanoates. Extreme tolerance exhibited by proteases has been attributed to the presence of some amino acids (Asn and Pro) in loop structures, relocation of multiple salt bridges to outer regions of the protein or the presence of a distinct polyproline II helix. The range of novel enzymes is projected to increase in the forthcoming years, as new isolates are being continually reported, and the development of processes involving such enzymes is envisaged in the future. PMID:25269602

Bennur, Tahsin; Kumar, Ameeta Ravi; Zinjarde, Smita; Javdekar, Vaishali

2014-11-01

325

Enhanced Clean Air Act enforcement  

SciTech Connect

The Clean Air Act Amendments of 1990 added new enforcement authorities which will change the way the US Environmental Protection Agency (EPA), the States and environmental groups litigate enforcement actions. EPA, the States and ordinary citizens now have at their disposal an extensive array of enforcement options to deter or penalize those who violate requirements of the Clean Air Act or State Implementation Plans (SIPs). These new enforcement authorities take on even greater significance for major sources covered by the Title V Operating Permit Program.

Faletto, J.S. [Howard and Howard Attorneys, Peoria, IL (United States)

1997-09-01

326

Enzymes of glucose metabolism in Frankia sp.  

PubMed

Enzymes of glucose metabolism were assayed in crude cell extracts of Frankia strains HFPArI3 and HFPCcI2 as well as in isolated vesicle clusters from Alnus rubra root nodules. Activities of the Embden-Meyerhof-Parnas pathway enzymes glucokinase, phosphofructokinase, and pyruvate kinase were found in Frankia strain HFPArI3 and glucokinase and pyruvate kinase were found in Frankia strain HFPCcI2 and in the vesicle clusters. An NADP+-linked glucose 6-phosphate dehydrogenase and an NAD-linked 6-phosphogluconate dehydrogenase were found in all of the extracts, although the role of these enzymes is unclear. No NADP+-linked 6-phosphogluconate dehydrogenase was found. Both dehydrogenases were inhibited by adenosine 5-triphosphate, and the apparent Km's for glucose 6-phosphate and 6-phosphogluconate were 6.86 X 10(-4) and 7.0 X 10(-5) M, respectively. In addition to the enzymes mentioned above, an NADP+-linked malic enzyme was detected in the pure cultures but not in the vesicle clusters. In contrast, however, the vesicle clusters had activity of an NAD-linked malic enzyme. The possibility that this enzyme resulted from contamination from plant mitochondria trapped in the vesicle clusters could not be discounted. None of the extracts showed activities of the Entner-Doudoroff enzymes or the gluconate metabolism enzymes gluconate dehydrogenase or gluconokinase. Propionate- versus trehalose-grown cultures of strain HFPArI3 showed similar activities of most enzymes except malic enzyme, which was higher in the cultures grown on the organic acid. Nitrogen-fixing cultures of strain HFPArI3 showed higher specific activities of glucose 6-phosphate and 6-phosphogluconate dehydrogenases and phosphofructokinase than ammonia-grown cultures. PMID:3980434

Lopez, M F; Torrey, J G

1985-04-01

327

Tandem conjugation of enzyme and antibody on silica nanoparticle for enzyme immunoassay  

Microsoft Academic Search

We present a new type of enzyme–antibody conjugate that simplifies the labeling procedure and increases the sensitivity of enzyme-linked immunosorbent assay (ELISA). The conjugates were prepared through layer-by-layer immobilization of enzyme and antibody on a silica nanoparticle scaffold. A maximal amount of enzyme was immobilized on the nanoparticle, followed by antibody linkage through Dextran 500. The conjugate could be easily

Rongqin Ke; Wei Yang; Xiaohu Xia; Ye Xu; Qingge Li

2010-01-01

328

The Americans with Disabilities Act  

Microsoft Academic Search

This study explored smaller businesses' understanding of and compliance with the Americans with Disabilities Act, particularly as it relates to the accommodation of people with physical versus mental disabilities. An ADA compliance score was developed for personnel practices regarding employees with physical and mental disabilities and a comparison of scores was made between employers who could recall any of the

R. Paul Maiden; Beverly Younger

1996-01-01

329

Antibiotics acting on the translational  

E-print Network

Antibiotics acting on the translational machinery Jörg M. Harms1,*, Heike Bartels1, Frank Schlünzen antibiotics, including vancomycin (the `last resort'), development of new antimicrobial agents has slowed during recent decades. To aid design of new antibiotics, we must develop a detailed understanding

Yonath, Ada E.

330

76 FR 59073 - Privacy Act  

Federal Register 2010, 2011, 2012, 2013, 2014

...PA), the Central Intelligence Agency (CIA) has undertaken and completed a review...regulations to more clearly reflect the current CIA organizational structure and policies and...Consistent with the Privacy Act (PA), the CIA has undertaken and completed a review...

2011-09-23

331

Implementing the Reading Excellence Act.  

ERIC Educational Resources Information Center

This slide presentation outlines one state's (Utah) version of implementation of a model for literacy learning under the Reading Excellence Act (REA). According to the presentation, the model is called "The Utah Reads K-3 Literacy Model." The presentation is divided into the following sections: Utah's Vision: What We've Learned So Far; One…

Lacy, Laurie; Dole, Janice; Donaldson, Becky; Donaldson, Brady

332

An Explanation of Act 917.  

ERIC Educational Resources Information Center

Arkansas' new finance law, Act 917, is difficult to understand because it has not been logically organized. This paper explains in detail the following provisions of the law: average daily membership (ADM) computation; local share; minimum and maximum millage; state support (including how priorities are set and the forms of state aid not covered,…

Schoppmeyer, Martin W.

333

MAJOR PROGRAMS ACTG Acting [BFA  

E-print Network

[BA] or [BS] CMPE Computer Engineering [BS] CMSC Computer Science [BS] DANC Dance [BA] ECON Economics PHIL Philosophy [BA] PHYS Physics [BS] PHSE Physics Education [BA] POLI Political Science [BA] PSYC] Tracks: AC -Acting DP -Design Production VAAV Visual Arts [BA] Tracks: AR -Art History FV -Cinematic Arts

Maryland, Baltimore County, University of

334

Clery Act: Road to Compliance  

ERIC Educational Resources Information Center

The purpose of this study was to explore what factors served as impediments to institutional efforts to comply with Clery Act guidelines through the perceptions of campus law administrators. Statistical analyses were performed on data collected from an online survey, which was distributed to members of the International Association of Campus Law…

McNeal, Laura R.

2007-01-01

335

Act To Promote Adult Education.  

ERIC Educational Resources Information Center

An act of the German Lower Saxony Parliament to promote adult education is presented. It has 24 general provisions relating to the following: purpose of adult education, principle for promotion, conditions for promotions of establishments, independence of adult education, prerequisites and form of acknowledgement of entitlement to promotion,…

1970

336

Acting White: A Critical Review  

ERIC Educational Resources Information Center

The hypothesis of acting White has been heatedly debated and influential over the last 20 years or so in explaining the Black-White test score gap. Recently, economists have joined the debate and started providing new theoretical and empirical analyses of the phenomenon. This paper critically reviews the arguments that have been advanced to…

Sohn, Kitae

2011-01-01

337

Dual acting slit control mechanism  

NASA Technical Reports Server (NTRS)

A dual acting control system for mass spectrometers is described, which permits adjustment of the collimating slit width and centering of the collimating slit while using only one vacuum penetration. Coaxial shafts, each with independent vacuum bellows are used to independently move the entire collimating assembly or to adjust the slit dimension through a parallelogram linkage.

Struthoff, G. L. (inventor)

1980-01-01

338

ACT and General Cognitive Ability  

ERIC Educational Resources Information Center

Research on the SAT has shown a substantial correlation with measures of "g" such as the Armed Services Vocational Aptitude Battery (ASVAB). Another widely administered test for college admission is the American College Test (ACT). Using the National Longitudinal Survey of Youth 1979, measures of "g" were derived from the ASVAB and correlated with…

Koenig, Katherine A.; Frey, Meredith C.; Detterman, Douglas K.

2008-01-01

339

Bipolar DNA Translocation Contributes to Highly Processive DNA Unwinding by RecBCD Enzyme*S  

E-print Network

Bipolar DNA Translocation Contributes to Highly Processive DNA Unwinding by RecBCD Enzyme*SBCD enzyme is a bipolar DNA helicase that employs two single-stranded DNA motors of opposite polarity the exceptionally high rate and processivity of DNA unwinding cata- lyzed by the RecBCD enzyme. Using a stopped

Kowalczykowski, Stephen C.

340

AN ENZYME-IMMOBILIZATION PROCEDURE FOR THE ANALYSIS OF ENZYME-INHIBITING CHEMICALS IN WATER  

EPA Science Inventory

The enzymes cholinesterase and urease were mixed individually with gelatin and immobilized onto the inside surface of glass capillary tubes. After the gelatin-enzyme mixture had dried, water samples containing various enzyme inhibiting test chemicals were pumped through the tubes...

341

Cross-linked polymer nanofibers for hyperthermophilic enzyme immobilization: approaches to improve enzyme performance.  

PubMed

We report an enzyme immobilization method effective at elevated temperatures (up to 105 °C) and sufficiently robust for hyperthermophilic enzymes. Using a model hyperthermophilic enzyme, ?-galactosidase from Thermotoga maritima, immobilization within chemically cross-linked poly(vinyl alcohol) (PVA) nanofibers to provide high specific surface area is achieved by (1) electrospinning a blend of a PVA and enzyme and (2) chemically cross-linking the polymer to entrap the enzyme within a water insoluble PVA fiber. The resulting enzyme-loaded nanofibers are water-insoluble at elevated temperatures, and enzyme leaching is not observed, indicating that the cross-linking effectively immobilizes the enzyme within the fibers. Upon immobilization, the enzyme retains its hyperthermophilic nature and shows improved thermal stability indicated by a 5.5-fold increase in apparent half-life at 90 °C, but with a significant decrease in apparent activity. The loss in apparent activity is attributed to enzyme deactivation and mass transfer limitations. Improvements in the apparent activity can be achieved by incorporating a cryoprotectant during immobilization to prevent enzyme deactivation. For example, immobilization in the presence of trehalose improved the apparent activity by 10-fold. Minimizing the mat thickness to reduce interfiber diffusion was a simple and effective method to further improve the performance of the immobilized enzyme. PMID:25058141

Tang, Christina; Saquing, Carl D; Morton, Stephen W; Glatz, Brittany N; Kelly, Robert M; Khan, Saad A

2014-08-13

342

DIGESTIVE ENZYMES IN POIKILOTHERMAL VERTEBRATES. AN INVESTIGATION OF ENZYMES IN FISHES, WITH COM-  

E-print Network

DIGESTIVE ENZYMES IN POIKILOTHERMAL VERTEBRATES. AN INVESTIGATION OF ENZYMES IN FISHES, WITH COM in the digestive tract_un Peptic digestionn __ Esophagus _ Stomach _ Page 181 Results and discussion-Continued. 182 Tryptic digestion uu u_ 182 Ereptic digestion u n _ 186 Carbohydrate-splitting enzymes _ 184 Amylase _ 184

343

Biocatalytic material comprising multilayer enzyme coated fiber  

DOEpatents

The present invention relates generally to high stability, high activity biocatalytic materials and processes for using the same. The materials comprise enzyme aggregate coatings having high biocatalytic activity and stability useful in heterogeneous environment. These new materials provide a new biocatalytic immobilized enzyme system with applications in bioconversion, bioremediation, biosensors, and biofuel cells.

Kim, Jungbae [Richland, WA; Kwak, Ja Hun [Richland, WA; Grate, Jay W [West Richland, WA

2009-11-03

344

Restriction Enzyme Mapping: A Simple Student Practical.  

ERIC Educational Resources Information Center

An experiment that uses the recombinant plasmid pX1108 to illustrate restriction mapping is described. The experiment involves three restriction enzymes and employs single and double restriction enzyme digestions. A list of needed materials, procedures, safety precautions, results, and discussion are included. (KR)

Higgins, Stephen J.; And Others

1990-01-01

345

Enzyme Activity Experiments Using a Simple Spectrophotometer  

ERIC Educational Resources Information Center

Experimental procedures for studying enzyme activity using a Spectronic 20 spectrophotometer are described. The experiments demonstrate the effect of pH, temperature, and inhibitors on enzyme activity and allow the determination of Km, Vmax, and Kcat. These procedures are designed for teaching large lower-level biochemistry classes. (MR)

Hurlbut, Jeffrey A.; And Others

1977-01-01

346

Kemp elimination catalysts by computational enzyme design  

E-print Network

ARTICLES Kemp elimination catalysts by computational enzyme design Daniela Ro¨thlisberger1 *, Olga motifs to catalyse the Kemp elimination--a model reaction for proton transfer from carbon--with measured no naturally occurring enzyme exists: the Kemp elimination5,6 . The reaction, shown in Fig. 1a, has been

Tawfik, Dan S.

347

KINEXP: Computer Simulation in Enzyme Kinetics.  

ERIC Educational Resources Information Center

Describes a program which allows students to identify and characterize several kinetic inhibitory mechanisms. Uses the generic model of reversible inhibition of a monosubstrate enzyme but can be easily modified to run other models such as bisubstrate enzymes. Uses MS-DOS BASIC. (MVL)

Gelpi, Josep Lluis; Domenech, Carlos

1988-01-01

348

Quantum Mechanical Methods for Enzyme Kinetics  

Microsoft Academic Search

This review discusses methods for the incorporation of quantum mechanical effects into enzyme kinetics simulations in which the enzyme is an explicit part of the model. We emphasize three aspects: (a) use of quantum mechanical electronic structure methods such as molecular orbital theory and density functional theory, usually in conjunction with molecular mechanics; (b) treating vibrational motions quantum mechanically, either

Jiali Gao; Donald G. Truhlar

2002-01-01

349

Immobilized enzymes and cells as practical catalysts  

Microsoft Academic Search

Performance of enzymes and whole cells in commercial applications can often be dramatically improved by immobilization of the biocatalysts, for instance, by their covalent attachment to or adsorption on solid supports, entrapment in polymeric gels, encapsulation, and cross-linking. The effect of immobilization on enzymatic properties and stability of biocatalysts is considered. Applications of immobilized enzymes and cells in the chemical,

A. M. Klibanov

1983-01-01

350

ENZYME ISOFORMS MAY INCREASE PHENOTYPIC ROBUSTNESS  

Microsoft Academic Search

Enzyme isoforms are found in many cellular reactions, and can differ in the kind of reaction they catalyze, in their substrate affinity, or in their reaction rates. The evolutionary significance of enzyme isoforms is only partially understood. We used mathematical modeling to investigate the hypothesis that isoforms may be favored by selection because they can increase the phenotypic robustness of

Maurizio Tomaiuolo; Richard Bertram; David Houle

2008-01-01

351

A DNA enzyme that cleaves RNA  

NASA Technical Reports Server (NTRS)

BACKGROUND: Several types of RNA enzymes (ribozymes) have been identified in biological systems and generated in the laboratory. Considering the variety of known RNA enzymes and the similarity of DNA and RNA, it is reasonable to imagine that DNA might be able to function as an enzyme as well. No such DNA enzyme has been found in nature, however. We set out to identify a metal-dependent DNA enzyme using in vitro selection methodology. RESULTS: Beginning with a population of 10(14) DNAs containing 50 random nucleotides, we carried out five successive rounds of selective amplification, enriching for individuals that best promote the Pb(2+)-dependent cleavage of a target ribonucleoside 3'-O-P bond embedded within an otherwise all-DNA sequence. By the fifth round, the population as a whole carried out this reaction at a rate of 0.2 min-1. Based on the sequence of 20 individuals isolated from this population, we designed a simplified version of the catalytic domain that operates in an intermolecular context with a turnover rate of 1 min-1. This rate is about 10(5)-fold increased compared to the uncatalyzed reaction. CONCLUSIONS: Using in vitro selection techniques, we obtained a DNA enzyme that catalyzes the Pb(2+)-dependent cleavage of an RNA phosphoester in a reaction that proceeds with rapid turnover. The catalytic rate compares favorably to that of known RNA enzymes. We expect that other examples of DNA enzymes will soon be forthcoming.

Breaker, R. R.; Joyce, G. F.; Hoyce, G. F. (Principal Investigator)

1994-01-01

352

Directed evolution of enzymes for applied biocatalysis  

Microsoft Academic Search

Directed evolution has rapidly emerged as a powerful new strategy for improving the characteristics of enzymes in a targeted manner. By coupling various protocols for generating large variant libraries of genes, together with high-throughput screens that select for specific properties of an enzyme, such as thermostability, catalytic activity and substrate specificity, it is now possible to optimize biocatalysts for specific

Nicholas J Turner

2003-01-01

353

Enzyme Catalysis and the Gibbs Energy  

ERIC Educational Resources Information Center

Gibbs-energy profiles are often introduced during the first semester of organic chemistry, but are less often presented in connection with enzyme-catalyzed reactions. In this article I show how the Gibbs-energy profile corresponds to the characteristic kinetics of a simple enzyme-catalyzed reaction. (Contains 1 figure and 1 note.)

Ault, Addison

2009-01-01

354

Enzyme loaded biodegradable microspheres in vitro  

Microsoft Academic Search

Prolidase is a naturally occurring enzyme involved in the final stage of protein catabolism. Deficient enzyme activity causes prolidase deficiency (PD), a rare autosomal recessive inherited disorder whose main manifestations are chronic, intractable ulcerations of the skin, particularly of lower limbs. Although several attempts have been made towards the treatment of this pathology, a cure for this disease has yet

I Genta; P Perugini; F Pavanetto; K Maculotti; T Modena; B Casado; A Lupi; P Iadarola; B Conti

2001-01-01

355

The evolution of enzyme kinetic power.  

PubMed Central

Evolution of the kinetic potential of enzyme reactions is discussed. Quantitative assessment of the evolution of enzyme action has usually focused on optimization of the parametric ratio kcat./Km, which is the apparent second-order rate constant for the reaction of free substrate with free enzyme to give product. We propose that the general form kcat.[E]T/Km (where [E]T is total enzyme concentration), which is designated the 'kinetic power', is the real measure of kinetic/catalytic potential in situ. The standard paradigm of 'perfection' dictates the evolutionary maximum of 'kinetic power' to be k+s[E]T/2, where k+s is the diffusion-controlled rate constant for formation of the ES complex (and, hence, for the overall enzyme reaction). We discuss the role of protein conformational mobility in determining this state of 'perfection', via gating of substrate binding and determination of the catalytic configuration. Going beyond the level of the individual enzyme, we indicate the manner by which the organizational features of enzyme action in vivo may enhance the 'kinetic power'. Through evolutionary 'perfection' of the microenvironment, one finds that the 'kinetic power' of enzymes can be affected by alteration of [E]T as well as the unitary rate constants. At this level of complexity, we begin to realize that the 'kinetic' description of cell metabolism must be supplemented with thermodynamic concepts. PMID:6497848

Keleti, T; Welch, G R

1984-01-01

356

Developing enzyme systems for biomass deconstruction  

Technology Transfer Automated Retrieval System (TEKTRAN)

The conversion of agricultural crops and residues to fermentable feedstock for the production of bioethanol represents a major source of renewable energy. The key to economically viable and effective biomass conversion includes the development of novel enzymes and enzyme systems to achieve total de...

357

Enzymes: A Workshop for Secondary School Students.  

ERIC Educational Resources Information Center

Describes the weekend science workshop on enzymes and includes several projects that involve students directly, parts of which can be incorporated into a traditional chemistry, biology, or physical science course at the secondary level. Subjects include catalysts and catalytic converters in cars, enzymes as consumer products and in industrial…

Bering, C. Larry

1994-01-01

358

Imaging of enzyme replacement therapy using PET  

PubMed Central

Direct enzyme replacement therapy (ERT) has been introduced as a means to treat a number of rare, complex genetic conditions associated with lysosomal dysfunction. Gaucher disease was the first for which this therapy was applied and remains the prototypical example. Although ERT using recombinant lysosomal enzymes has been shown to be effective in altering the clinical course of Gaucher disease, Fabry disease, Hurler syndrome, Hunter syndrome, Maroteaux-Lamy syndrome, and Pompe disease, the recalcitrance of certain disease manifestations underscores important unanswered questions related to dosing regimes, tissue half-life of the recombinant enzyme and the ability of intravenously administered enzyme to reach critical sites of known disease pathology. We have developed an innovative method for tagging acid ?-glucocerebrosidase (GCase), the recombinant enzyme formulated in Cerezyme® used to treat Gaucher disease, using an 18F-labeled substrate analogue that becomes trapped within the active site of the enzyme. Using micro-PET we show that the tissue distribution of injected enzyme can be imaged in a murine model and that the PET data correlate with tissue 18F counts. Further we show that PET imaging readily monitors pharmacokinetic changes effected by receptor blocking. The ability to 18F-label GCase to monitor the enzyme distribution and tissue half-life in vivo by PET provides a powerful research tool with an immediate clinical application to Gaucher disease and a clear path for application to other ERTs. PMID:20534487

Phenix, Christopher P.; Rempel, Brian P.; Colobong, Karen; Doudet, Doris J.; Adam, Michael J.; Clarke, Lorne A.; Withers, Stephen G.

2010-01-01

359

Potential applications of oxidative enzymes and phenoloxidase-like compounds in wastewater and soil treatment: a review  

Microsoft Academic Search

A number of oxidative enzymes from bacteria, fungi and plants have been reported to play an important role in numerous waste treatment applications. Peroxidases and\\/or phenoloxidases can act on specific recalcitrant pollutants by precipitation or transforming to other products and permitting a better final treatment of the waste. Improvement in the useful life and thereby a reduction in treatment cost

Nelson Durán; Elisa Esposito

2000-01-01

360

Substrate analogues for isoprenoid enzymes  

SciTech Connect

Diphosphonate analogues of geranyl diphosphate, resistant to degradation by phosphatases, were found to be alternate substrates for the reaction with farnesyl diphosphate synthetase isolated from avian liver. The difluoromethane analogue was shown to be the better alternate substrate, in agreement with solvolysis results which indicate that the electronegativity of the difluoromethylene unit more closely approximates that of the normal bridging oxygen. The usefulness of the C/sub 10/ difluoro analogue, for detecting low levels of isoprenoid enzymes in the presence of high levels of phosphatase activity, was demonstrated with a cell-free preparation from lemon peel. A series of C/sub 5/ through C/sub 15/ homoallylic and allylic diphosphonates, as well as two 5'-nucleotide diphosphonates, was prepared in high overall yield using the activation-displacement sequence. Radiolabeled samples of several of the allylic diphosphonates were prepared with tritium located at C1. A series of geraniols, stereospecifically deuterated at C1, was prepared. The enantiomeric purities and absolute configurations were determined by derivatization as the mandelate esters for analysis by /sup 1/H NMR. The stereochemistry of the activation-displacement sequence was examined using C1-deuterated substrates.

Stremler, K.E.

1987-01-01

361

Spectroscopic studies of copper enzymes  

SciTech Connect

Several spectroscopic methods, including absorption, circular dichroism (CD), magnetic CD (MCD), X-ray absorption, resonance Raman, EPR, NMR, and quasi-elastic light-scattering spectroscopy, have been used to probe the structures of copper-containing amine oxidases, nitrite reductase, and nitrous oxide reductase. The basic goals are to determine the copper site structure, electronic properties, and to generate structure-reactivity correlations. Collectively, the results on the amine oxidases permit a detailed model for the Cu(II) sites in these enzymes to be constructed that, in turn, rationalizes the ligand-binding chemistry. Resonance Raman spectra of the phenylhydrazine and 2,4-dinitrophenyl-hydrazine derivatives of bovine plasma amine oxidase and models for its organic cofactor, e.g. pyridoxal, methoxatin, are most consistent with methoxatin being the intrinsic cofactor. The structure of the Cu(I) forms of the amine oxidases have been investigated by X-ray absorption spectroscopy (XAS); the copper coordination geometry is significantly different in the oxidized and reduced forms. Some anomalous properties of the amine oxidases in solution are explicable in terms of their reversible aggregation, which the authors have characterized via light scattering. Nitrite and nitrous oxide reductases display several novel spectral properties. The data suggest that new types of copper sites are present.

Dooley, D.M.; Moog, R.; Zumft, W.; Koenig, S.H.; Scott, R.A.; Cote, C.E.; McGuirl, M.

1986-05-01

362

The effect of phospholipids on the biodegradation of polyurethanes by lysosomal enzymes  

Microsoft Academic Search

Although biodegradation of model poly(ester-urethane)s and poly(ether-urethane)s has been demonstrated using a single enzyme system (cholesterol esterase (CE)) in vitro, in vivo biodegradation most likely involves many processes acting together. In this study, the physical (film vs textured surface) and chemical (poly(urethane)s containing polycaprolactone (PCL) vs poly(tetramethylene oxide) (PTMO)) nature of the materials as well as the products of enzymatic

Rosalind S. Labow; J. Paul Santerre; Girija Waghray

1997-01-01

363

Acts of Commanding and Changing Obligations  

Microsoft Academic Search

If we are to take the notion of speech act seriously, we must be able to treat speech acts as acts. In what follows, I will try to model changes brought about by various acts of commanding in terms of a variant of update logic. I will combine a multi-agent variant of the language of monadic deontic logic with a

Tomoyuki Yamada

2006-01-01

364

Lignocellulolytic enzyme profiles of edible mushroom fungi.  

PubMed

One of the most economically-viable processes for the bioconversion of many types of lignocellulosic wastes is represented by edible mushroom cultivation. Lentinula edodes, Volvariella volvacea and Pleurotus sajor-caju are three important commercially cultivated mushrooms which exhibit varying abilities to utilise different lignocellulosics as growth substrate. Examination of the lignocellulolytic enzyme profiles of the three species show this diversity to be reflected in qualitative variations in the major enzymic determinants (i.e. cellulases, ligninases) required for substrate bioconversion. For example, L. edodes, which is cultivated on highly lignified substrates such as wood or sawdust, produces two extracellular enzymes which have been associated with lignin depolymerisation in other fungi, (manganese peroxidase and laccase). Conversely, V. volvacea, which prefers high cellulose-, low lignin-containing substrates produces a family of cellulolytic enzymes including at least five endoglucanases, five cellobiohydrolases and two ?-glucosidases, but none of the recognised lignin-degrading enzymes. PMID:24415386

Buswell, J A; Cai, Y J; Chang, S T; Peberdy, J F; Fu, S Y; Yu, H S

1996-09-01

365

Angiotensin-converting enzyme inhibitor-induced angioedema.  

PubMed

Angiotensin-converting enzyme inhibitors (ACE-I) are widely used, effective, and well-tolerated antihypertensive agents. The mechanisms by which those agents act can cause side effects such as decreased blood pressure, hyperkalemia, and impaired renal function. ACE-I can induce cough in 5%-35% and angioedema in up to 0.7% of treated patients. Because cough and angioedema are considered class adverse effects, switching treatment to other ACE-I agents is not recommended. Angioedema due to ACE-I has a low fatality rate, although deaths have been reported when the angioedema involves the airways. Here, we review the role of bradykinin in the development of angioedema in patients treated with ACE-I, as well as the incidence, risk factors, clinical presentation, and available treatments for ACE-I-induced angioedema. We also discuss the risk for recurrence of angioedema after switching from ACE-I to angiotensin receptor blockers treatment. PMID:25058867

Bezalel, Shira; Mahlab-Guri, Keren; Asher, Ilan; Werner, Ben; Sthoeger, Zev Moshe

2015-02-01

366

19 CFR 113.68 - Wool and fur products labeling acts and fiber products identification act bond conditions.  

Code of Federal Regulations, 2011 CFR

...Wool and fur products labeling acts and fiber products identification act bond conditions...Wool and fur products labeling acts and fiber products identification act bond conditions...wool and fur products labeling acts and fiber products identification act shall...

2011-04-01

367

19 CFR 113.68 - Wool and fur products labeling acts and fiber products identification act bond conditions.  

Code of Federal Regulations, 2010 CFR

...Wool and fur products labeling acts and fiber products identification act bond conditions...Wool and fur products labeling acts and fiber products identification act bond conditions...wool and fur products labeling acts and fiber products identification act shall...

2010-04-01

368

Enzyme stabilization by glass-derived silicates in glass-exposed aqueous solutions  

USGS Publications Warehouse

Objectives: To analyze the solutes leaching from glass containers into aqueous solutions, and to show that these solutes have enzyme activity stabilizing effects in very dilute solutions. Methods: Enzyme assays with acetylcholine esterase were used to analyze serially succussed and diluted (SSD) solutions prepared in glass and plastic containers. Aqueous SSD preparations starting with various solutes, or water alone, were prepared under several conditions, and tested for their solute content and their ability to affect enzyme stability in dilute solution. Results: We confirm that water acts to dissolve constituents from glass vials, and show that the solutes derived from the glass have effects on enzymes in the resultant solutions. Enzyme assays demonstrated that enzyme stability in purified and deionized water was enhanced in SSD solutions that were prepared in glass containers, but not those prepared in plastic. The increased enzyme stability could be mimicked in a dose-dependent manner by the addition of silicates to the purified, deionized water that enzymes were dissolved in. Elemental analyses of SSD water preparations made in glass vials showed that boron, silicon, and sodium were present at micromolar concentrations. Conclusions: These results show that silicates and other solutes are present at micromolar levels in all glass-exposed solutions, whether pharmaceutical or homeopathic in nature. Even though silicates are known to have biological activity at higher concentrations, the silicate concentrations we measured in homeopathic preparations were too low to account for any purported in vivo efficacy, but could potentially influence in vitro biological assays reporting homeopathic effects. ?? 2009 The Faculty of Homeopathy.

Ives, J.A.; Moffett, J.R.; Arun, P.; Lam, D.; Todorov, T.I.; Brothers, A.B.; Anick, D.J.; Centeno, J.; Namboodiri, M.A.A.; Jonas, W.B.

2010-01-01

369

Lipid bilayer nanodisc platform for investigating polyprenol-dependent enzyme interactions and activities  

PubMed Central

Membrane-bound polyprenol-dependent pathways are important for the assembly of essential glycoconjugates in all domains of life. However, despite their prevalence, the functional significance of the extended linear polyprenyl groups in the interactions of the glycan substrates, the biosynthetic enzymes that act upon them, and the membrane bilayer in which they are embedded remains a mystery. These interactions are investigated simultaneously and uniquely through application of the nanodisc membrane technology. The Campylobacter jejuni N-linked glycosylation pathway has been chosen as a model pathway in which all of the enzymes and substrates are biochemically accessible. We present the functional reconstitution of two enzymes responsible for the early membrane-committed steps in glycan assembly. Protein stoichiometry analysis, fluorescence-based approaches, and biochemical activity assays are used to demonstrate the colocalization of the two enzymes in nanodiscs. Isotopic labeling of the substrates reveals that undecaprenyl-phosphate is coincorporated into discs with the two enzymes, and furthermore, that both enzymes are functionally reconstituted and can sequentially convert the coembedded undecaprenyl-phosphate into undecaprenyl-diphosphate-linked disaccharide. These studies provide a proof-of-concept demonstrating that the nanodisc model membrane system represents a promising experimental platform for analyzing the multifaceted interactions among the enzymes involved in polyprenol-dependent glycan assembly pathways, the membrane-associated substrates, and the lipid bilayer. The stage is now set for exploration of the roles of the conserved polyprenols in promoting protein–protein interactions among pathway enzymes and processing of substrates through sequential steps in membrane-associated glycan assembly. PMID:24302767

Hartley, Meredith D.; Schneggenburger, Philipp E.; Imperiali, Barbara

2013-01-01

370

Immobilized enzymes in organic media: Determinants of water dependence. Progress statement  

SciTech Connect

The overall goals of this project are to investigate the critical factors that limit commercial scale applications of enzymes in organic solvents, and to scale-up a process for the production of a precursor to a specialty polymer. The overall performance of an immobilized enzyme can be influenced by its intrinsic structure and by external factors such as water content, support, pH, etc.. We have investigated the interrelation between support morphology and water content, and its effect on overall enzyme performance. Using a lipase catalyzed inter-esterification reaction as a model, we studied the controlling factors when water content in the organic solvent is such that a micro-aqueous phase is formed. In such an environment it was found that support particle aggregation is the major cause for decline in enzyme activity. We have shown that particle porosity, as well as the use of a particular non-woven fabric as an enzyme support, could alleviate this problem. These findings are being translated into a bioreactor design. We have also studied two {open_quotes}dry{close_quotes} non-aqueous systems, where a water phase is not formed since the water content is below its solubility in the organic solvent. In one of the systems, Subtilisin catalyzed trans-esterification of vinyl acrylate with a chiral alcohol, we have demonstrated that the use of a proprietary fabric support provides a significant boost in enzyme activity. We suggest that this particular fabric with its hydrophilic fibers acts as a lyoprotectant in the process of drying the enzyme. The benefits of this material as an enzyme support and its use in a lab scale bioreactor are being studied. Preliminary experiments have also been performed with a second {open_quotes}dry{close_quotes} reaction. This is the lipase catalyzed synthesis of AlliedSignal`s new product, VEctomer 4010.

Nandi, S.; DeFilippi, I.; Bedwell, B.; Zemel, H.

1994-08-01

371

The chain-flipping mechanism of ACP (acyl carrier protein)-dependent enzymes appears universal.  

PubMed

ACPs (acyl carrier proteins) play essential roles in the synthesis of fatty acids, polyketides and non-ribosomal polypeptides. ACP function requires the modification of the protein by attachment of 4'-phosphopantetheine to a conserved serine residue. The phosphopantetheine thiol acts to tether the starting materials and intermediates as their thioesters. ACPs are small highly soluble proteins composed of four ?-helices. The helices form a bundle that acts as a hydrophobic sleeve that sequesters the acyl chains and activated thioesters from solvent. However, in the synthesis of fatty acids and complex lipids the enzymes of the pathway must access the thioester and the proximal carbon atoms in order to perform the needed chemistry. How such access is provided without exposure of the acyl chains to solvent has been a longstanding question due to the lack of acyl-ACP-enzyme complexes, a situation generally attributed to the brevity of the interactions of acyl-ACPs with their cognate enzymes. As discussed in the present review the access question has now been answered by four recent crystal structures, each of which shows that the entire acyl chain plus the 4'-phosphopantetheine prosthetic group partitions from the ACP hydrophobic sleeve into a hydrophobic pocket or groove of the enzyme protein, a process termed chain flipping. PMID:24825445

Cronan, John E

2014-06-01

372

Sucrose:Fructan 6-Fructosyltransferase, a Key Enzyme for Diverting Carbon from Sucrose to Fructan in Barley Leaves.  

PubMed Central

Sucrose:sucrose 6-fructosyltransferase, an enzyme activity recently identified in fructan-accumulating barley (Hordeum vulgare) leaves, was further characterized. The purified enzyme catalyzed the transfer of a fructosyl group from sucrose to various acceptors. It displayed some [beta]-fructosidase (invertase) activity, indicating that water could act as fructosyl acceptor. Moreover, it transferred the fructosyl residue of unlabeled sucrose to [U-14C]Glc, producing [U-14C]sucrose and unlabeled glucose. Most significantly for fructan synthesis, the enzyme used as acceptors but not as donors a variety of oligofructans containing [beta](2->1)- and [beta](2->6)-linked fructosyl moieties. Thus, it acted as a general sucrose:fructan fructosyltransferase. The products formed by the enzyme from sucrose and various purified, structurally characterized oligofructans were analyzed by liquid chromatography and identified by comparison with structurally characterized standards. The results showed that the enzyme formed exclusively [beta](2->6) fructosyl-fructose linkages, either initiating or elongating a fructan chain of the phlein type. We propose, therefore, to rename the purified enzyme sucrose:fructan 6-fructosyltransferase. PMID:12228431

Duchateau, N.; Bortlik, K.; Simmen, U.; Wiemken, A.; Bancal, P.

1995-01-01

373

Purification and properties of an enzyme capable of degrading the sheath of Sphaerotilus natans.  

PubMed

Microorganisms which can degrade and grow on the purified sheath of a sheathed bacterium Sphaerotilus natans were collected from soil and river water. Two bacterial strains were isolated from the soil and designated strains TB and TK. Both strains are rod shaped, negatively stained by gram staining, facultatively anaerobic, and formed ellipsoidal endospores. These characteristics suggested that the isolates belong to the genus Paenibacillus, according to Ash et al. (C. Ash, F. G. Priest, and M. D. Collins, Antonie Leeuwenhoek 64:253-260, 1993). Phylogenetic analysis based on the 16S rDNA supported this possibility. Purification of the sheath-degrading enzyme was carried out from the culture broth of strain TB. The molecular weight of the enzyme was calculated to be 78,000 and 50, 000 by sodium dodecyl sulfate-polyacrylamide electrophoresis and gel filtration chromatography, respectively. Enzyme activity was optimized at pH 6.5 to 7.0 and 30 to 40 degrees C. The reaction was accelerated by the addition of Mg(2+), Ca(2+), Fe(3+), and iodoacetamide, whereas it was inhibited by the addition of Cu(2+), Mn(2+), and dithiothreitol. The enzyme acted on the polysaccharide moiety of the sheath, producing an oligosaccharide the size of which was between the sizes of maltopentaose and maltohexaose. As the reaction proceeded, the absorbance at 235 nm of the reaction mixture increased, suggesting the generation of unsaturated sugars. Incorporation of unsaturated sugars was also suggested by the thiobarbituric acid reaction. It is possible that the enzyme is not a hydrolytic enzyme but a kind of polysaccharide eliminase which acts on the basic polysaccharide. PMID:11055955

Takeda, M; Iohara, K; Shinmaru, S; Suzuki, I; Koizumi, J I

2000-11-01

374

Purification and Properties of an Enzyme Capable of Degrading the Sheath of Sphaerotilus natans  

PubMed Central

Microorganisms which can degrade and grow on the purified sheath of a sheathed bacterium Sphaerotilus natans were collected from soil and river water. Two bacterial strains were isolated from the soil and designated strains TB and TK. Both strains are rod shaped, negatively stained by gram staining, facultatively anaerobic, and formed ellipsoidal endospores. These characteristics suggested that the isolates belong to the genus Paenibacillus, according to Ash et al. (C. Ash, F. G. Priest, and M. D. Collins, Antonie Leeuwenhoek 64:253–260, 1993). Phylogenetic analysis based on the 16S rDNA supported this possibility. Purification of the sheath-degrading enzyme was carried out from the culture broth of strain TB. The molecular weight of the enzyme was calculated to be 78,000 and 50,000 by sodium dodecyl sulfate-polyacrylamide electrophoresis and gel filtration chromatography, respectively. Enzyme activity was optimized at pH 6.5 to 7.0 and 30 to 40°C. The reaction was accelerated by the addition of Mg2+, Ca2+, Fe3+, and iodoacetamide, whereas it was inhibited by the addition of Cu2+, Mn2+, and dithiothreitol. The enzyme acted on the polysaccharide moiety of the sheath, producing an oligosaccharide the size of which was between the sizes of maltopentaose and maltohexaose. As the reaction proceeded, the absorbance at 235 nm of the reaction mixture increased, suggesting the generation of unsaturated sugars. Incorporation of unsaturated sugars was also suggested by the thiobarbituric acid reaction. It is possible that the enzyme is not a hydrolytic enzyme but a kind of polysaccharide eliminase which acts on the basic polysaccharide. PMID:11055955

Takeda, Minoru; Iohara, Keishi; Shinmaru, Sachie; Suzuki, Ichiro; Koizumi, Jun-Ichi

2000-01-01

375

Inherited enzyme deficiencies in livestock.  

PubMed

The biochemical basis of over 300 inherited diseases has been defined in humans, and the majority involve abnormalities in enzymes. The rate of discovery of new defects is accelerating as biochemical and molecular technologies improve. The majority of inherited defects are expressed before puberty and approximately 25% are apparent at birth. Genomes of other mammals are similar and have been subjected to similar mutation pressures; therefore, it is probable that a range of inherited defects exists in livestock similar to that in humans. Because modern livestock populations have emerged from small population bases, the range of genetic aberrations, within breeds, will be less than in the general human population. Even if there is a 10-fold difference, however, there will be a bewildering array of defects possible in each breed. Because the level of inbreeding within livestock populations is greater than in the general human population, on the other hand, the prevalence of specific defects will be higher. It is probable that a high prevalence of a lethal recessive defect could occur within a particular livestock population and escape recognition. First, livestock producers accept a relatively high neonatal mortality rate without seeking a diagnosis. Second, few if any veterinary diagnostic facilities possess either the instrumentation or the analytic skills essential for investigating the vast range of potential inborn errors of metabolism. Third, national selection programs--e.g., those employed within the dairy industry--tend to use production data from adult progeny in selection. Consequently, the programs would not detect differences in fetal or neonatal mortality rates among descendants of specific sires until a deleterious defect had been widely disseminated.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8457930

Healy, P J; Dennis, J A

1993-03-01

376

Process for preparing multilayer enzyme coating on a fiber  

DOEpatents

A process for preparing high stability, high activity biocatalytic materials is disclosed and processes for using the same. The process involves coating of a material or fiber with enzymes and enzyme aggregate providing a material or fiber with high biocatalytic activity and stability useful in heterogeneous environments. In one illustrative approach, enzyme "seeds" are covalently attached to polymer nanofibers followed by treatment with a reagent that crosslinks additional enzyme molecules to the seed enzymes forming enzyme aggregates thereby improving biocatalytic activity due to increased enzyme loading and enzyme stability. This approach creates a useful new biocatalytic immobilized enzyme system with potential applications in bioconversion, bioremediation, biosensors, and biofuel cells.

Kim, Jungbae (Richland, WA); Kwak, Ja Hun (Richland, WA); Grate, Jay W. (West Richland, WA)

2009-11-03

377

Potato Peroxidase for the Study of Enzyme Properties.  

ERIC Educational Resources Information Center

Explains how the surface of a freshly sliced potato can be used for a variety of enzyme action experiments including the influence of pH on enzyme action, the enzyme denaturation potential of boiling water, the inhibition of enzymes by heavy metals, and the effects of salt concentration on enzyme effectiveness. (PR)

Shamaefsky, Brian R.

1993-01-01

378

Molecular dynamics investigation of the ionic liquid/enzyme interface: Application to engineering enzyme surface charge.  

PubMed

Molecular simulations of the enzymes Candida rugosa lipase and Bos taurus ?-chymotrypsin in aqueous ionic liquids 1-butyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium ethyl sulfate were used to study the change in enzyme-solvent interactions induced by modification of the enzyme surface charge. The enzymes were altered by randomly mutating lysine surface residues to glutamate, effectively decreasing the net surface charge by two for each mutation. These mutations resemble succinylation of the enzyme by chemical modification, which has been shown to enhance the stability of both enzymes in ILs. After establishing that the enzymes were stable on the simulated time scales, we focused the analysis on the organization of the ionic liquid substituents about the enzyme surface. Calculated solvent charge densities show that for both enzymes and in both solvents that changing positively charged residues to negative charge does indeed increase the charge density of the solvent near the enzyme surface. The radial distribution of IL constituents with respect to the enzyme reveals decreased interactions with the anion are prevalent in the modified systems when compared to the wild type, which is largely accompanied by an increase in cation contact. Additionally, the radial dependence of the charge density and ion distribution indicates that the effect of altering enzyme charge is confined to short range (?1 nm) ordering of the IL. Ultimately, these results, which are consistent with that from prior experiments, provide molecular insight into the effect of enzyme surface charge on enzyme stability in ILs. Proteins 2015; 83:670-680. © 2015 Wiley Periodicals, Inc. PMID:25641162

Burney, Patrick R; Nordwald, Erik M; Hickman, Katie; Kaar, Joel L; Pfaendtner, Jim

2015-04-01

379

The "Death Squad Protection" Act  

NSDL National Science Digital Library

This very important new electronic briefing book from the National Security Archive (last mentioned in the January 28, 2000 Scout Report) offers analysis and background materials regarding a recently passed (July 13) measure in the FY 2001 Defense Authorization Act that -- if approved by the full Congress -- would severely reduce the amount of information released by the Defense Intelligence Agency (DIA) under the Freedom of Information Act (FOIA). These materials, especially the documents produced by the Defense HUMINT Service and routinely declassified in the past, have been central in many investigations of human rights violations committed by US-supported foreign military and intelligence units. At the site, users will find a summary of how the legislation will impact this research, sample documents that would have been withheld, the full text of the proposed exemption, background on the HUMINT Service, and HUMINT reports.

380

National Park Service: Antiquities Act  

NSDL National Science Digital Library

Established in 1906, The Antiquities Act was the first law to establish that archaeological sites on public lands are important public resources. This website was designed to commemorate the 100th anniversary of the Act, and should be considered rather essential for any persons interested in such matters. After browsing a basic overview of the Actâ??s primary provisions, visitors should consider the â??Monument Profilesâ?ť section. Within this well-thought out section, visitors can learn about such important sites as Devils Tower National Monument, Chaco Canyon, as well as a number of other locations. Another nice way to learn about these sites is to peruse the interactive maps offered in the â??Maps, Facts & Figuresâ?ť area. Finally, the site also contains complete details on the various events that will take place at these different sites over the coming year.

381

Microchip device for performing enzyme assays.  

PubMed

An automated enzyme assay was performed within a microfabricated channel network. Precise concentrations of substrate, enzyme, and inhibitor were mixed in nanoliter volumes using electrokinetic flow. Reagent dilution and mixing were controlled by regulating the applied potential at the terminus of each channel, using voltages derived from an equivalent circuit model of the microchip. The enzyme beta-galactosidase (beta-Gal) was assayed using resorufin beta-D-galactopyranoside (RBG), a substrate that is hydrolyzed to resorufin, a fluorescent product. Reaction kinetics were obtained by varying the concentration of substrate on-chip and monitoring the production of resorufin using laser-induced fluorescence. Derived Michaelis--Menten constants compared well between an on-chip and a conventional enzyme assay. Bias in the derived K(m) and kcat was primarily due to the limited solubility of RBG and the associated lack of measurements at substrate concentrations exceeding the K(m). A Ki of 8 microM for the inhibitor phenylethyl beta-D-thiogalactoside (PETG) was determined from plots of initial rate versus substrate concentration obtained at three concentrations of PETG. The relative inhibition of beta-Gal by lactose, p-hydroxymercuribenzoic acid, and PETG was determined by varying the inhibitor concentration with constant enzyme and substrate concentration. An enzyme assay performed on the microchip within a 20-min period required only 120 pg of enzyme and 7.5 ng of substrate, reducing the amount of reagent consumed by 4 orders of magnitude over a conventional assay. PMID:9286159

Hadd, A G; Raymond, D E; Halliwell, J W; Jacobson, S C; Ramsey, J M

1997-09-01

382

Enzyme Reaction Annotation Using Cloud Techniques  

PubMed Central

An understanding of the activities of enzymes could help to elucidate the metabolic pathways of thousands of chemical reactions that are catalyzed by enzymes in living systems. Sophisticated applications such as drug design and metabolic reconstruction could be developed using accurate enzyme reaction annotation. Because accurate enzyme reaction annotation methods create potential for enhanced production capacity in these applications, they have received greater attention in the global market. We propose the enzyme reaction prediction (ERP) method as a novel tool to deduce enzyme reactions from domain architecture. We used several frequency relationships between architectures and reactions to enhance the annotation rates for single and multiple catalyzed reactions. The deluge of information which arose from high-throughput techniques in the postgenomic era has improved our understanding of biological data, although it presents obstacles in the data-processing stage. The high computational capacity provided by cloud computing has resulted in an exponential growth in the volume of incoming data. Cloud services also relieve the requirement for large-scale memory space required by this approach to analyze enzyme kinetic data. Our tool is designed as a single execution file; thus, it could be applied to any cloud platform in which multiple queries are supported. PMID:24222895

Huang, Chuan-Ching

2013-01-01

383

Enzyme reaction annotation using cloud techniques.  

PubMed

An understanding of the activities of enzymes could help to elucidate the metabolic pathways of thousands of chemical reactions that are catalyzed by enzymes in living systems. Sophisticated applications such as drug design and metabolic reconstruction could be developed using accurate enzyme reaction annotation. Because accurate enzyme reaction annotation methods create potential for enhanced production capacity in these applications, they have received greater attention in the global market. We propose the enzyme reaction prediction (ERP) method as a novel tool to deduce enzyme reactions from domain architecture. We used several frequency relationships between architectures and reactions to enhance the annotation rates for single and multiple catalyzed reactions. The deluge of information which arose from high-throughput techniques in the postgenomic era has improved our understanding of biological data, although it presents obstacles in the data-processing stage. The high computational capacity provided by cloud computing has resulted in an exponential growth in the volume of incoming data. Cloud services also relieve the requirement for large-scale memory space required by this approach to analyze enzyme kinetic data. Our tool is designed as a single execution file; thus, it could be applied to any cloud platform in which multiple queries are supported. PMID:24222895

Huang, Chuan-Ching; Lin, Chun-Yuan; Chang, Cheng-Wen; Tang, Chuan Yi

2013-01-01

384

Immobilization of enzymes on PTFE surfaces.  

PubMed

Membranes and powders prepared from PTFE (polytetrafluorethylene) were investigated for their potential use as multifunctional supports for enzymes. The obtained bioactive materials are valuable for the construction of biosensors and enzyme reactors. To allow covalent coupling of enzymes to PTFE, the surface of the material was treated with elementary sodium followed by oxidation with ozone or hydrogen peroxide.%Derivatization steps were optimized in order to achieve highest enzyme loading and short reaction times. Alliinase (EC 4.4.1.4) and L-lactic dehydrogenase (EC 1.1.1.27) were chosen as model enzymes and were either immobilized by covalent coupling or fixed indirectly by a sugar-lectin binding. For the latter method, the sugar mannan was bound to the membrane surface as an anchor for layers of the lectin concanavalin A and the alliinase. Highest alliinase loading was achieved at 0.2 microg x cm(-2). Immobilization of alliinase via the lectin concanavalin A and a bifunctional epoxide gave the best long-term stability.%L-Lactic dehydrogenase was most sufficiently immobilized by using benzoquinone as spacer. These procedures show several advantages: 1) enzymes can be immobilized under physiological conditions, 2) an enzyme-multilayer can be achieved, and 3) protein layers are renewable. PMID:11460243

Keusgen, M; Glodek, J; Milka, P; Krest, I

2001-03-01

385

Clean Air Act. Revision 5  

SciTech Connect

This Reference Book contains a current copy of the Clean Air Act, as amended, and those regulations that implement the statute and appear to be most relevant to DOE activities. The document is provided to DOE and contractor staff for informational purposes only and should not be interpreted as legal guidance. This Reference Book has been completely revised and is current through February 15, 1994.

Not Available

1994-02-15

386

The new Clean Air Act  

SciTech Connect

This article is a title by title review of the new Clean Air Act and how it affects water quality and wastewater treatment. The bill provides for restoring and protecting lakes and rivers by reducing acid-rain-causing emissions and toxics from nonpoint-source runoff. Topics covered include urban smog, mobile sources, air toxics, acid rain, permits, ozone-depleting chemicals, enforcement, and the law's socio-economic impacts.

Padmanabha, A.P. (Blue Plains Wastewater Treatment Plant, Washington, DC (United States)); Olem, H. (Olem Associates, Washington, DC (United States))

1991-05-01

387

SCADA Application for ACTS Technology  

NASA Technical Reports Server (NTRS)

The results of a system level study done by Hughes Network Systems for NASA are presented. For the supervisory control and data acquisition (SCADA) application, use of Ka-band spot beam satellite technology associated with NASA's Advanced Communication Technology Satellite (ACTS) offers a reduction in Earth station antenna size and transmitter power that may translate into lower system costs. The approaches taken to determine commercial potential of the system are described.

Fairbanks, Barry

1992-01-01

388

Mapping enzyme active sites in complex proteomes.  

PubMed

Genome sequencing projects have uncovered many novel enzymes and enzyme classes for which knowledge of active site structure and mechanism is limited. To facilitate mechanistic investigations of the numerous enzymes encoded by prokaryotic and eukaryotic genomes, new methods are needed to analyze enzyme function in samples of high biocomplexity. Here, we describe a general strategy for profiling enzyme active sites in whole proteomes that utilizes activity-based chemical probes coupled with a gel-free analysis platform. We apply this gel-free strategy to identify the sites of labeling on enzymes targeted by sulfonate ester probes. For each enzyme examined, probe labeling was found to occur on a conserved active site residue, including catalytic nucleophiles (e.g., C32 in glutathione S-transferase omega) and bases/acids (e.g., E269 in aldehyde dehydrogenase-1; D204 in enoyl CoA hydratase-1), as well as residues of unknown function (e.g., D127 in 3 beta-hydroxysteroid dehydrogenase/isomerase-1). These results reveal that sulfonate ester probes are remarkably versatile activity-based profiling reagents capable of labeling a diversity of catalytic residues in a range of mechanistically distinct enzymes. More generally, the gel-free strategy described herein, by consolidating into a single step the identification of both protein targets of activity-based probes and the specific residues labeled by these reagents, provides a novel platform in which the proteomic comparison of enzymes can be accomplished in unison with a mechanistic analysis of their active sites. PMID:14759193

Adam, Gregory C; Burbaum, Jonathan; Kozarich, John W; Patricelli, Matthew P; Cravatt, Benjamin F

2004-02-11

389

Acting Internships: Course name and number: Acting Internship New Orleans: MEDC 400 (Required Medicine), 418  

E-print Network

Acting Internships: Course name and number: Acting Internship ­ New Orleans: MEDC 400 (Required Medicine), 418 (Secondary Acting Internship), 419 (Primary Acting Internship) Available Hospitals: LSU: 4 weeks Availability: Senior acting internships may be taken as an elective if spots are available

390

Safe Drinking Water Act (SDWA): A Summary of the Act and Its Major Requirements  

E-print Network

Safe Drinking Water Act (SDWA): A Summary of the Act and Its Major Requirements Mary Tiemann c11173008 . #12;Safe Drinking Water Act (SDWA): A Summary of the Act and Its Major Requirements Congressional Research Service Summary This report summarizes the Safe Drinking Water Act (SDWA) and its major

Firestone, Jeremy

391

Antioxidant enzyme deficiencies and vascular disease  

PubMed Central

Cellular respiration in an oxygen-rich environment leads to the generation of reactive oxygen species. These partially reduced forms of molecular oxygen can readily react with biological molecules, often modifying their normal biological function. Antioxidant enzyme mechanisms have evolved to eliminate reactive oxygen species and minimize the oxidant stress caused by their reactivity. Inherited and acquired deficiencies of key antioxidant enzymes lead to a dysregulated redox environment, which can promote pathobiology; when this redox dysfunction occurs in the blood vessel, vascular disease ensues. In this article, we consider three distinct antioxidant enzyme deficiencies – glucose-6-phosphate dehydrogenase, glutathione peroxidase-1 and glutathione peroxidase-3 – and their consequences for vascular disease. PMID:20190873

Loscalzo, Joseph

2010-01-01

392

BIOCHEMISTRY: Enzyme Motions Inside and Out  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. How does an enzyme reduce the free-energy barrier for a chemical transformation? The authors have reviewed the progression of hypothetical answers to this question and identified a common feature of the various rationales--namely, the requirement for conformational flexibility within the enzyme and substrates. They also discuss how Masgrau et al. examined the importance of dynamics for catalysis by the enzyme aromatic amine dehydrogenase in the oxidation of tryptamine.

Stephen J. Benkovic (Pennsylvania State University; Department of Chemistry)

2006-04-14

393

Immobilization of enzymes by bioaffinity layering.  

PubMed

Bioaffinity immobilization exploits the affinity of the enzyme to a macro-(affinity ligand). Such a macro-(affinity ligand) could be a lectin, a water-soluble polymer, or a bioconjugate of a water-soluble polymer and the appropriate affinity ligand. Successive layering of the enzyme and the macro-(affinity ligand) on a matrix allows deposition of a large amount of enzyme activity on a small surface. Illustrative protocols show affinity layering of a pectinase and horseradish peroxidase on Concanavalin A-agarose and Concanavalin A-Sephadex matrices, respectively. PMID:23934802

Singh, Veena; Sardar, Meryam; Gupta, Munishwar Nath

2013-01-01

394

Visualizing enzyme infusion into apple tissue.  

PubMed

Enzymes traditionally used in food processing are applied to ground or macerated tissue with little or no retention of cellular structure. More recently developed applications use enzymes to selectively alter tissue properties while retaining some structure. Process development has been hindered by the lack of conclusive evidence showing that enzyme infusion into plant tissue pieces is possible. This study provides direct evidence that such infusion is possible by using fluorescence microscopy to monitor vacuum infusion of fluorescein-labeled alpha-amylase into apple cubes. This method is generally applicable to any plant or animal tissue and to any macromolecule capable of derivatization. PMID:11141264

Culver, C A; Bjurlin, M A; Fulcher, R G

2000-12-01

395

Dual control mechanism for heme oxygenase: tin(IV)-protoporphyrin potently inhibits enzyme activity while markedly increasing content of enzyme protein in liver.  

PubMed Central

Tin(IV)-protoporphyrin (Sn-protoporphyrin) potently inhibits heme degradation to bile pigments in vitro and in vivo, a property that confers upon this synthetic compound the ability to suppress a variety of experimentally induced and naturally occurring forms of jaundice in animals and humans. Utilizing rat liver heme oxygenase purified to homogeneity together with appropriate immunoquantitation techniques, we have demonstrated that Sn-protoporphyrin possesses the additional property of potently inducing the synthesis of heme oxygenase protein in liver cells while, concurrently, completely inhibiting the activity of the newly formed enzyme. Substitution of tin for the central iron atom of heme thus leads to the formation of a synthetic heme analogue that regulates heme oxygenase by a dual mechanism, which involves competitive inhibition of the enzyme for the natural substrate heme and simultaneous enhancement of new enzyme synthesis. Cobaltic(III)-protoporphyrin (Co-protoporphyrin) also inhibits heme oxygenase activity in vitro, but unlike Sn-protoporphyrin it greatly enhances the activity of the enzyme in the whole animal. Co-protoporphyrin also acts as an in vivo inhibitor of heme oxygenase; however, its inducing effect on heme oxygenase synthesis is so pronounced as to prevail in vivo over its inhibitory effect on the enzyme. These studies show that certain synthetic heme analogues possess the ability to simultaneously inhibit as well as induce the enzyme heme oxygenase in liver. The net balance between these two actions, as reflected in the rate of heme oxidation activity in the whole animal, appears to be influenced by the nature of the central metal atom of the synthetic metalloporphyrin. Images PMID:3470805

Sardana, M K; Kappas, A

1987-01-01

396

Acts related to solid waste management in Illinois. Annual report  

SciTech Connect

;Contents: Degradable Plastic Act; Energy Assistance Act of 1989; Hazardous and Solid Waste Recycling and Treatment Act; Illinois Emergency Planning and Community Right to Know Act; Illinois Environmental Facilities Financing Act; Illinois Purchasing Act; Illinois Solid Waste Management Act; Intergovernmental Cooperation Act; Junkyard Act; Litter Control Act; Local Hazardous Waste Collection Program Act; Local Solid Waste Disposal Act; Metro East Solid Waste Disposal and Energy Producing Service Act; Recycled Newsprint Use Act; Responsible Property Transfer Act of 1988; Solid Waste Disposal District Act; Solid Waste Planning and Recycling Act; Solid Waste Site Operator Certification Law; Township Refuse, Collection and Disposal Act; Toxic Pollution Prevention Act; Used Motor Oil Recycling Act; Waste Oil Recovery Act; and Water Supply, Drainage and Flood Control.

Not Available

1994-04-01

397

Impact of enzyme loading on the efficacy and recovery of cellulolytic enzymes immobilized on enzymogel nanoparticles.  

PubMed

Cellulase and ?-glucosidase were adsorbed on a polyacrylic acid polymer brush grafted on silica nanoparticles to produce enzymogels as a form of enzyme immobilization. Enzyme loading on the enzymogels was increased to a saturation level of approximately 110 ?g (protein) mg(-1) (particle) for each enzyme. Enzymogels with varied enzyme loadings were then used to determine the impact on hydrolysis rate and enzyme recovery. Soluble sugar concentrations during the hydrolysis of filter paper and Solka-Floc with the enzymogels were 45 and 53%, respectively, of concentrations when using free cellulase. ?-Glucosidase enzymogels showed lower performance; hydrolyzate glucose concentrations were just 38% of those using free enzymes. Increasing enzyme loading on the enzymogels did not reduce net efficacy for cellulase and improved efficacy for ?-glucosidase. The use of free cellulases and cellulase enzymogels resulted in hydrolyzates with different proportions of cellobiose and glucose, suggesting differential attachment or efficacy of endoglucanases, exoglucanases, and ?-glucosidases present in cellulase mixtures. When loading ?-glucosidase individually, higher enzyme loadings on the enzymogels produced higher hydrolyzate glucose concentrations. Approximately 96% of cellulase and 66 % of ?-glucosidase were recovered on the enzymogels, while enzyme loading level did not impact recovery for either enzyme. PMID:25564204

Samaratunga, Ashani; Kudina, Olena; Nahar, Nurun; Zakharchenko, Andrey; Minko, Sergiy; Voronov, Andriy; Pryor, Scott W

2015-03-01

398

Real-time monitoring of enzyme activity in a mesoporous silicon double layer  

PubMed Central

A double layer mesoporous silicon with different pore sizes functions as a nano-reactor that can isolate, filter and quantify the kinetics of enzyme reactions in real-time by optical reflectivity. This tiny reactor may be used to rapidly characterize a variety of isolated enzymes in a label-free manner. Activity of certain protease enzymes is often an indicator of disease states such as cancer1,2, stroke2, and neurodegeneracy3, and thus, there is a need for rapid assays that can characterize the kinetics and substrate specificity of enzymatic reactions. Nanostructured membranes can efficiently separate biomolecules4 but coupling a sensitive detection method remains difficult. Here we report a single mesoporous nano-reactor that can isolate and quantify in real-time the reaction products of proteases. The reactor consists of two layers of porous films electrochemically prepared from crystalline silicon. The upper layer with large pore sizes traps the protease enzymes and acts as the reactor while the lower layer with smaller pore sizes excludes the large proteins and captures the reaction products. Infiltration of the digested fragments into the lower layer produces a measurable change in optical reflectivity and this allows label-free quantification of enzyme kinetics in real-time within a volume of approximately 5 nanoliters. PMID:19350037

Orosco, Manuel M.; Pacholski, Claudia; Sailor, Michael J.

2009-01-01

399

Production of keratinolytic enzyme by an indigenous feather-degrading strain Bacillus cereus Wu2.  

PubMed

A novel feather-degrading microorganism was isolated from a poultry farm in Taiwan, and was identified Bacillus cereus Wu2 according to 16S rRNA sequencing. The isolated strain produces keratinolytic enzyme using chicken feather as the sole carbon and nitrogen source. The experimental results indicated that the extra carbon sources (glucose, fructose, starch, sucrose, or lactose) could act as a catabolite repressor to the enzyme secretion or keratinolytic activity when keratinous substrates were employed as protein sources. However, addition of 2 g/L of NH(4)Cl to the feather medium increased the enzyme production. The optimum temperature and initial pH for enzyme production were 30°C and 7.0, respectively. The maximum yield of the enzyme was 1.75 kU/mL in the optimal chicken feather medium; this value was about 17-fold higher than the yield in the basal hair medium. The B. cereus Wu2 possessed disulfide reductase activity along with keratinolytic activity. The amino acid contents of feathers degradated by B. cereus Wu2 were higher, especially for lysine, methionine and threonine which were nutritionally essential amino acids and usually deficient in the feather meal. Thus, B. cereus Wu2 could be not only used to enhance the nutritional value of feather meal but is also a potential bioinoculant in agricultural environments. PMID:22999356

Lo, Wei-Hsun; Too, Jui-Rze; Wu, Jane-Yii

2012-12-01

400

Concomitant production of detergent compatible enzymes by Bacillus flexus XJU-1  

PubMed Central

A soil screened Bacillus flexus XJU-1 was induced to simultaneously produce alkaline amylase, alkaline lipase and alkaline protease at their optimum levels on a common medium under submerged fermentation. The basal cultivation medium consisted of 0.5% casein, 0.5% starch and 0.5% cottonseedoil as an inducer forprotease, amylase, and lipase, respectively. The casein also served as nitrogen source for all 3 enzymes. The starch was also found to act as carbon source additive for both lipase and protease. Maximum enzyme production occurred on fermentation medium with 1.5% casein, 1.5% soluble starch, 2% cottonseed oil, 2% inoculum size, initial pH of 11.0, incubation temperature of 37 °C and 1% soybean meal as a nitrogen source supplement. The analysis of time course study showed that 24 h was optimum incubation time for amylase whereas 48 h was the best time for both lipase and protease. After optimization, a 3.36-, 18.64-, and 27.33-fold increase in protease, amylase and lipase, respectively was recorded. The lipase was produced in higher amounts (37.72 U/mL) than amylase and protease about 1.27 and 5.85 times, respectively. As the 3 enzymes are used in detergent formulations, the bacterium can be commercially exploited to secrete the alkaline enzymes for use in detergent industry. This is the first report for concomitant production of 3 alkaline enzymes by a bacterium. PMID:25477924

Niyonzima, Francois N.; More, Sunil S.

2014-01-01

401

Gold nanoparticles bound on microgel particles and their application as an enzyme support  

NASA Astrophysics Data System (ADS)

Submicron-sized poly(N-isopropyl acrylamide)/polyethyleneimine core-shell microgels were prepared in aqueous media by using tert-butyl hydroperoxide (TBHP) as an initiator, and then the gold nanoparticles (~8 nm) were formed on the surface of the microgels. The amino groups on the polyethyleneimine (PEI) chains act as the binder for the assembly of the gold nanoparticles/microgel complex. In aqueous media the microgels are highly stable with the gold nanoparticles on their extended PEI chains, and this multi-scale nanoparticle complex can be recovered from water and redispersed in water. The nanogold/microgel particles were conjugated with the enzymes horseradish peroxidase (HRP) and urease. It is found that under identical assay conditions the enzyme/nanogold/microgel systems exhibit enhanced biocatalytic activity over free enzymes in solution, especially at lower enzyme concentrations. In addition, compared to free HRP, the HRP/nanogold/microgel systems show higher activity at varied pHs and temperatures, as well as higher storage stability. Thus the novel nanogold/microgel particles can serve as an excellent support for enzymes.

Xu, Jing; Zeng, Fang; Wu, Shuizhu; Liu, Xinxing; Hou, Chao; Tong, Zhen

2007-07-01

402

21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Drug metabolizing enzyme genotyping system. 862.3360 Section...Systems § 862.3360 Drug metabolizing enzyme genotyping system. (a) Identification . A drug metabolizing enzyme genotyping system is a device...

2011-04-01

403

21 CFR 862.2500 - Enzyme analyzer for clinical use.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Enzyme analyzer for clinical use. 862.2500...Laboratory Instruments § 862.2500 Enzyme analyzer for clinical use. (a) Identification. An enzyme analyzer for clinical use is a...

2010-04-01

404

21 CFR 862.2500 - Enzyme analyzer for clinical use.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Enzyme analyzer for clinical use. 862.2500...Laboratory Instruments § 862.2500 Enzyme analyzer for clinical use. (a) Identification. An enzyme analyzer for clinical use is a...

2011-04-01

405

21 CFR 864.9400 - Stabilized enzyme solution.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Stabilized enzyme solution. 864.9400 Section 864...Blood Products § 864.9400 Stabilized enzyme solution. (a) Identification. A stabilized enzyme solution is a reagent intended for...

2011-04-01

406

21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Drug metabolizing enzyme genotyping system. 862.3360 Section...Systems § 862.3360 Drug metabolizing enzyme genotyping system. (a) Identification. A drug metabolizing enzyme genotyping system is a device...

2014-04-01

407

21 CFR 862.2500 - Enzyme analyzer for clinical use.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Enzyme analyzer for clinical use. 862.2500...Laboratory Instruments § 862.2500 Enzyme analyzer for clinical use. (a) Identification. An enzyme analyzer for clinical use is a...

2013-04-01

408

21 CFR 862.2500 - Enzyme analyzer for clinical use.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Enzyme analyzer for clinical use. 862.2500...Laboratory Instruments § 862.2500 Enzyme analyzer for clinical use. (a) Identification. An enzyme analyzer for clinical use is a...

2014-04-01

409

21 CFR 864.9400 - Stabilized enzyme solution.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Stabilized enzyme solution. 864.9400 Section 864...Blood Products § 864.9400 Stabilized enzyme solution. (a) Identification. A stabilized enzyme solution is a reagent intended for...

2013-04-01

410

21 CFR 862.2500 - Enzyme analyzer for clinical use.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Enzyme analyzer for clinical use. 862.2500...Laboratory Instruments § 862.2500 Enzyme analyzer for clinical use. (a) Identification. An enzyme analyzer for clinical use is a...

2012-04-01

411

21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Drug metabolizing enzyme genotyping system. 862.3360 Section...Systems § 862.3360 Drug metabolizing enzyme genotyping system. (a) Identification . A drug metabolizing enzyme genotyping system is a device...

2013-04-01

412

21 CFR 864.9400 - Stabilized enzyme solution.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Stabilized enzyme solution. 864.9400 Section 864...Blood Products § 864.9400 Stabilized enzyme solution. (a) Identification. A stabilized enzyme solution is a reagent intended for...

2014-04-01

413

21 CFR 864.9400 - Stabilized enzyme solution.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Stabilized enzyme solution. 864.9400 Section 864...Blood Products § 864.9400 Stabilized enzyme solution. (a) Identification. A stabilized enzyme solution is a reagent intended for...

2012-04-01

414

BLEACHABILITY OF RECYCLED FIBERS DEINKED WITH ENZYME PREPARATIONS  

E-print Network

BLEACHABILITY OF RECYCLED FIBERS DEINKED WITH ENZYME PREPARATIONS Marguerite Sykes John Klungness the recycling emphasis from ink removal to color removal. Our research indicates that enzymes can available enzyme preparations used for deinking office wastepaper on pulp brightness and bleachability

Abubakr, Said

415

Enzyme mimics: Halogen and chalcogen team up  

NASA Astrophysics Data System (ADS)

The behaviour of di-selenol enzyme mimics indicates that a halogen bond between selenium and iodine, and a chalcogen interaction between the two selenium atoms, play an important role in the activation of thyroid hormones.

Metrangolo, Pierangelo; Resnati, Giuseppe

2012-06-01

416

Enzyme Reactions in Nanoporous, Picoliter Volume Containers  

SciTech Connect

Advancements in nanoscale fabrication allow creation of small volume reaction containers that can facilitate the screening and characterization of enzymes. A porous, ~19 pL volume vessel has been used in this work to carry out enzyme reactions under varying substrate concentrations. Glucose oxidase and horseradish peroxidase can be contained in these structures and diffusively fed with a solution containing glucose and the fluorogenic substrate Amplex Red through the engineered nanoscale pore structure. Fluorescent microscopy was used to monitor the reaction, which was carried out under microfluidic control. Kinetic characteristics of the enzyme were evaluated and compared with results from conventional scale reactions. These picoliter, nanoporous containers can facilitate quick determination of enzyme kinetics in microfluidic systems without the requirement of surface tethering and can be used for applications in drug discovery, clinical diagnostics and high-throughput screening.

Siuti, Piro [ORNL; Retterer, Scott T [ORNL; Choi, Chang Kyoung [Michigan Technological University; Doktycz, Mitchel John [ORNL

2012-01-01

417

Practical Enzyme Kinetics: A Biochemical Laboratory Experiment.  

ERIC Educational Resources Information Center

Describes an experiment that provides a fundamental understanding of the kinetics of the enzyme papain. Discusses background, materials, procedures and results. Mentions analogous experiments that can be conducted with enzymatic contact-lens cleaning solutions. (CW)

Rowe, H. Alan; Brown, Morris

1988-01-01

418

ZnO-Based Amperometric Enzyme Biosensors  

PubMed Central

Nanostructured ZnO with its unique properties could provide a suitable microenvironment for immobilization of enzymes while retaining their biological activity, and thus lead to an expanded use of this nanomaterial for the construction of electrochemical biosensors with enhanced analytical performance. ZnO-based enzyme electrochemical biosensors are summarized in several tables for an easy overview according to the target biosensing analyte (glucose, hydrogen peroxide, phenol and cholesterol), respectively. Moreover, recent developments in enzyme electrochemical biosensors based on ZnO nanomaterials are reviewed with an emphasis on the fabrications and features of ZnO, approaches for biosensor construction (e.g., modified electrodes and enzyme immobilization) and biosensor performances. PMID:22205864

Zhao, Zhiwei; Lei, Wei; Zhang, Xiaobing; Wang, Baoping; Jiang, Helong

2010-01-01

419

Enzymes as Chemotherapeutic Agents Ronald T. Raines  

E-print Network

Genentech) is used as an aerosol to cleave DNA in the lungs of cystic fibrosis patients. Tissue plasminogen of enzymes to be chemotherapeutic agents, focusing on mammalian ribonucleases for the treatment of cancer. R

Raines, Ronald T.

420

Enzymes as useful tools for environmental purposes.  

PubMed

In the environment enzymes may play important and different roles at least in three cases: as main agents (as isolated, cell-bound or immobilized enzymes) in charge of either the transformation and/or degradation of compounds polluting the environment and the restoration of the polluted environment; as reliable and sensitive tools to detect and measure the amount and concentration of pollutants before, during and after the restoration process; as reliable, easy and sensitive indicators of quality and health status of the environment subjected to the restoration process. To our knowledge papers or reviews integrating findings on these three functions of enzymes are missing in literature. Therefore the main scope of the present paper is to briefly encompass general and specific concepts about roles of enzymes as decontaminating agents, pollutant assaying agents and indicators of environment safety. Examples chosen among those published very recently, supporting and confirming peculiarities, features, and performance of enzymatic agents will be illustrated. PMID:24411841

Rao, M A; Scelza, R; Acevedo, F; Diez, M C; Gianfreda, L

2014-07-01

421

Bacterial lipolytic enzymes: classification and properties.  

PubMed Central

Knowledge of bacterial lipolytic enzymes is increasing at a rapid and exciting rate. To obtain an overview of this industrially very important class of enzymes and their characteristics, we have collected and classified the information available from protein and nucleotide databases. Here we propose an updated and extensive classification of bacterial esterases and lipases based mainly on a comparison of their amino acid sequences and some fundamental biological properties. These new insights result in the identification of eight different families with the largest being further divided into six subfamilies. Moreover, the classification enables us to predict (1) important structural features such as residues forming the catalytic site or the presence of disulphide bonds, (2) types of secretion mechanism and requirement for lipase-specific foldases, and (3) the potential relationship to other enzyme families. This work will therefore contribute to a faster identification and to an easier characterization of novel bacterial lipolytic enzymes. PMID:10493927

Arpigny, J L; Jaeger, K E

1999-01-01

422

Microbial Enzymes: Tools for Biotechnological Processes  

PubMed Central

Microbial enzymes are of great importance in the development of industrial bioprocesses. Current applications are focused on many different markets including pulp and paper, leather, detergents and textiles, pharmaceuticals, chemical, food and beverages, biofuels, animal feed and personal care, among others. Today there is a need for new, improved or/and more versatile enzymes in order to develop more novel, sustainable and economically competitive production processes. Microbial diversity and modern molecular techniques, such as metagenomics and genomics, are being used to discover new microbial enzymes whose catalytic properties can be improved/modified by different strategies based on rational, semi-rational and random directed evolution. Most industrial enzymes are recombinant forms produced in bacteria and fungi. PMID:24970208

Adrio, Jose L.; Demain, Arnold L.

2014-01-01

423

A Quantitative Enzyme Study Using Simple Equipment  

NSDL National Science Digital Library

This resource consists of a simple laboratory exercise examining the effects different variables on enzyme-catalysed reactions rates. Background information, instructor notes, and suggested questions and laboratory report exercises are provided.

Linda B. Cholewiak (Princeton University; )

1991-01-01

424

Stress-Induced Enzyme Compounds Methamphetamine Neurotoxicity  

MedlinePLUS

... has side effects, including gastrointestinal bleeding. Implications Beyond Drug Abuse The finding that neuroinflammation can damage dopamine and ... this article APA style citation National Institute on Drug Abuse. Stress-Induced Enzyme Compounds Methamphetamine Neurotoxicity Retrieved from ...

425

Detoxification of aromatic pollutants by fungal enzymes  

SciTech Connect

Fungal enzymes, such as laccase, peroxidase, and tyrosinase, play a prominent role in catalyzing the transformation of various aromatic compounds in the environment. The enzyme-mediated oxidative coupling reaction results in covalent binding of chlorinated phenols and anilines to soil organic matter or polymerization of the substrates in aquatic systems. Both of these processes are accompanied by a detoxification effect. Therefore, it has been postulated that they be exploited for the treatment of polluted soil and water. The mechanism and efficiency of oxidative coupling in pollutant removal were studied by incubation of chlorinated phenols and anilines with various humic substances or soil and analysis of the reaction products by chromatography and mass and {sup 13}C nuclear magnetic resonance (NMR) spectrometry. The decontamination effect could be enhanced by optimization of the reaction conditions and immobilization of enzymes on solid materials. The results obtained strongly support the concept of using enzymes for control of environmental pollution.

Bollag, J.M.; Dec, J. [Pennsylvania State Univ., University Park, PA (United States)

1995-12-31

426

Halophilic enzyme activation induced by salts  

PubMed Central

Halophilic archea (halobacteriae) thrive in hypersaline environments, avoiding osmotic shock by increasing the ion concentration of their cytoplasm by up to 3–6 M. To remain folded and active, their constitutive proteins have evolved towards a biased amino acid composition. High salt concentration affects catalytic activity in an enzyme-dependent way and a unified molecular mechanism remains elusive. Here, we have investigated a DNA ligase from Haloferax volcanii (Hv LigN) to show that K+ triggers catalytic activity by preferentially stabilising a specific conformation in the reaction coordinate. Sodium ions, in turn, do not populate such isoform and the enzyme remains inactive in the presence of this co-solute. Our results show that the halophilic amino acid signature enhances the enzyme's thermodynamic stability, with an indirect effect on its catalytic activity. This model has been successfully applied to reengineer Hv LigN into an enzyme that is catalytically active in the presence of NaCl. PMID:22355525

Ortega, Gabriel; Laín, Ana; Tadeo, Xavier; López-Méndez, Blanca; Castańo, David; Millet, Oscar

2011-01-01

427

Non-neuronal acetylcholine, a locally acting molecule, widely distributed in biological systems: Expression and function in humans  

Microsoft Academic Search

Acetylcholine acts as a neurotransmitter in the central and peripheral nervous systems in humans. However, recent experiments demonstrate a widespread expression of the cholinergic system in non-neuronal cells in humans. The synthesizing enzyme choline acetyltransferase, the signalling molecule acetylcholine, and the respective receptors (nicotinic or muscarinic) are expressed in epithelial cells (human airways, alimentary tract, epidermis). Acetylcholine is also found

Ignaz Wessler; Charles James Kirkpatrick; Kurt Racké

1998-01-01

428

New enzymes involved in aerobic benzoate metabolism in Azoarcus evansii.  

PubMed

A new principle of aerobic aromatic metabolism has been postulated, which is in contrast to the known pathways. In various bacteria the aromatic substrate benzoate is first converted to its coenzyme A (CoA) thioester, benzoyl-CoA, which is subsequently attacked by an oxygenase, followed by a non-oxygenolytic fission of the ring. We provide evidence for this hypothesis and show that benzoyl-CoA conversion in the bacterium Azoarcus evansii requires NADPH, O(2) and two protein components, BoxA and BoxB. BoxA is a homodimeric 46 kDa iron-sulphur-flavoprotein, which acts as reductase. In the absence of BoxB, BoxA catalyses the benzoyl-CoA stimulated artificial transfer of electrons from NADPH to O(2) via free FADH(2) to produce H(2)O(2). Physiologically, BoxA uses NADPH to reduce BoxB, a monomeric 55 kDa iron-protein that acts as benzoyl-CoA oxygenase. The product of benzoyl-CoA oxidation was identified by NMR spectroscopy as its dihydrodiol derivative, 2,3-dihydro-2,3-dihydroxybenzoyl-CoA. This suggests that BoxBA act as a benzoyl-CoA dioxygenase/reductase. Unexpectedly, benzoyl-CoA transformation by BoxBA was greatly stimulated when another enoyl-CoA hydratase/isomerase-like protein, BoxC, was added that catalysed the further transformation of the dihydrodiol product formed from benzoyl-CoA. The benzoyl-CoA oxygenase system has very low similarity to known (di)oxygenase systems and is the first member of a new enzyme family. PMID:15458418

Zaar, Annette; Gescher, Johannes; Eisenreich, Wolfgang; Bacher, Adelbert; Fuchs, Georg

2004-10-01

429

Cyanide-degrading enzymes for bioremediation  

E-print Network

prepared after their genes were cloned with N-terminal hexahistidine purification tags, expressed in Escherichia coli and purified using immobilized metal affinity chromatography. These enzymes were compared according to their relative specific activity... of Serratia nuclease (29) before centrifugation at 3750 rpm for 15 minutes. The supernatant was then clarified with a 0.45#2;m filter. The hexahistidine-tagged cyanide hydratase enzymes were purified from crude cell lysates by immobilized metal affinity...

Basile, Lacy Jamel

2008-10-10

430

Building proficient enzymes with foldamer prostheses.  

PubMed

Foldamers are non-natural oligomers that adopt stable conformations reminiscent of those found in proteins. To evaluate the potential of foldameric subunits for catalysis, semisynthetic enzymes containing foldamer fragments constructed from ?- and ?-amino acid residues were designed and characterized. Systematic variation of the ??? substitution pattern and types of ?-residue afforded highly proficient hybrid catalysts, thus demonstrating the feasibility of expanding the enzyme-engineering toolkit with non-natural backbones. PMID:24828837

Mayer, Clemens; Müller, Manuel M; Gellman, Samuel H; Hilvert, Donald

2014-07-01

431

Enzyme activity and dynamics of Drosophila development  

Microsoft Academic Search

The length of preadult development is negatively correlated with the activity of a majority of studied enzymes, in adult D. melanogaster and D. subobscura flies. This has been shown when activities of seven enzymes (G6PD, 6PGD, aGPD, ADH, HK, ME & IDH) were estimated per mg of protein, or of body mass, in four groups of 6-days old males (50

D. Marinkovié; M. Miloševi?; M. Milanovi?

1986-01-01

432

Extracellular enzyme kinetics scale with resource availability  

USGS Publications Warehouse

Microbial community metabolism relies on external digestion, mediated by extracellular enzymes that break down complex organic matter into molecules small enough for cells to assimilate. We analyzed the kinetics of 40 extracellular enzymes that mediate the degradation and assimilation of carbon, nitrogen and phosphorus by diverse aquatic and terrestrial microbial communities (1160 cases). Regression analyses were conducted by habitat (aquatic and terrestrial), enzyme class (hydrolases and oxidoreductases) and assay methodology (low affinity and high affinity substrates) to relate potential reaction rates to substrate availability. Across enzyme classes and habitats, the scaling relationships between apparent Vmax and apparent Km followed similar power laws with exponents of 0.44 to 0.67. These exponents, called elasticities, were not statistically distinct from a central value of 0.50, which occurs when the Km of an enzyme equals substrate concentration, a condition optimal for maintenance of steady state. We also conducted an ecosystem scale analysis of ten extracellular hydrolase activities in relation to soil and sediment organic carbon (2,000–5,000 cases/enzyme) that yielded elasticities near 1.0 (0.9 ± 0.2, n = 36). At the metabolomic scale, the elasticity of extracellular enzymatic reactions is the proportionality constant that connects the C:N:P stoichiometries of organic matter and ecoenzymatic activities. At the ecosystem scale, the elasticity of extracellular enzymatic reactions shows that organic matter ultimately limits effective enzyme binding sites. Our findings suggest that one mechanism by which microbial communities maintain homeostasis is regulating extracellular enzyme expression to optimize the short-term responsiveness of substrate acquisition. The analyses also show that, like elemental stoichiometry, the fundamental attributes of enzymatic reactions can be extrapolated from biochemical to community and ecosystem scales.

Sinsabaugh, Robert L.; Belnap, Jayne; Findlay, Stuart G.; Follstad Shah, Jennifer J.; Hill, Brian H.; Kuehn, Kevin A.; Kuske, Cheryl; Litvak, Marcy E.; Martinez, Noelle G.; Moorhead, Daryl L.; Warnock, Daniel D.

2014-01-01

433

Dry-Enzyme Test For Gaseous Chemicals  

NASA Technical Reports Server (NTRS)

Simple, dry-chemical test detects ethanol in human breath. Method of test also adapted to detection of such toxic chemicals as formaldehyde in airstreams. Used qualitatively to detect chemical compounds above present level; for example, ethanol above legal level for driving. Also used to indicate quantitatively concentrations of compounds. Involves dry enzyme and color indicator. Adapted to detect any gaseous compound transformed by enzymes to produce change evident to human eye or to instrument.

Barzana, Eduardo; Karel, Marcus; Klibanov, Alexander

1990-01-01

434

Chromatin remodeling enzymes: who's on first?  

Microsoft Academic Search

A central problem in the regulation of eukaryotic gene expression is understanding how gene-specific transcriptional activators orchestrate the recruitment of the myriad proteins that are required for transcription initiation. An emerging view indicates that activators must first target two types of chromatin remodeling enzyme to the promoter region: an ATP-dependent SWI\\/SNF-like complex and a histone acetyltransferase. These two enzymes appear

Christopher J Fry; Craig L Peterson

2001-01-01

435

Plant peroxiredoxins: alternative hydroperoxide scavenging enzymes  

Microsoft Academic Search

The role of plant peroxiredoxins in the detoxification systems is discussed in relation with the existence of many isoforms\\u000a of this protein in distinct plant compartments. Phylogenetic analyses indicate that plant peroxiredoxins can be divided into\\u000a four classes. Two of these classes correspond to chloroplastic enzymes. All isoforms contain at least one conserved catalytic\\u000a cysteine. The enzymes belonging to the

Nicolas Rouhier; Jean-Pierre Jacquot

2002-01-01

436

Enzyme replacement therapy of fabry disease  

Microsoft Academic Search

Fabry disease is an X-linked lysosomal storage disease caused by deficiency of the enzyme ?-galactosidase A and results in\\u000a pain, progressive renal impairment, cardiomyopathy, and cerebrovascular disease. The results of two major randomized, double-blind,\\u000a placebo-controlled clinical trials and open-label extensions have shown that replacement of the deficient enzyme with either\\u000a of two preparations of recombinant human ?-galactosidase A, agalsidase-alfa, and

Joe T. R. Clarke; R. Mark Iwanochko

2005-01-01

437

BIOCHEMISTRY: De Novo Design of an Enzyme  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Enzymes catalyze biological reactions with amazing efficiency, and years of biochemical research have been directed at understanding how they work. In their Perspective, Sterner and Schmid describe recent work (Dwyer et al.) that brings us closer to the ultimate goal of designing enzymes with tailored activities by using computer design to build catalytic activity onto an inert protein scaffold.

Reinhard Sterner (Universität Regensburg, Institut für Biophysik und Physikalische Biochemie; )

2004-06-25

438

Serum angiotensin converting enzyme in pulmonary disease  

Microsoft Academic Search

Synthetic acylated tripeptides, which may or may not be radiolabelled, are generally used as substrates for measuring serum\\u000a angiotensin converting enzyme (SACE) activity. The capillary endothelial cells are the major source of SACE in normals and\\u000a certain diseased states, however Gaucher’s cells in Gaucher’s disease and epithelioid cells in granulomatous disorders, including\\u000a sarcoidosis, are the major source of enzyme in

P. K. Rohatgi

1982-01-01

439

Ethylmalonyl-CoA Decarboxylase, a New Enzyme Involved in Metabolite Proofreading*  

PubMed Central

A limited number of enzymes are known that play a role analogous to DNA proofreading by eliminating non-classical metabolites formed by side activities of enzymes of intermediary metabolism. Because few such “metabolite proofreading enzymes” are known, our purpose was to search for an enzyme able to degrade ethylmalonyl-CoA, a potentially toxic metabolite formed at a low rate from butyryl-CoA by acetyl-CoA carboxylase and propionyl-CoA carboxylase, two major enzymes of lipid metabolism. We show that mammalian tissues contain a previously unknown enzyme that decarboxylates ethylmalonyl-CoA and, at lower rates, methylmalonyl-CoA but that does not act on malonyl-CoA. Ethylmalonyl-CoA decarboxylase is particularly abundant in brown adipose tissue, liver, and kidney in mice, and is essentially cytosolic. Because Escherichia coli methylmalonyl-CoA decarboxylase belongs to the family of enoyl-CoA hydratase (ECH), we searched mammalian databases for proteins of uncharacterized function belonging to the ECH family. Combining this database search approach with sequencing data obtained on a partially purified enzyme preparation, we identified ethylmalonyl-CoA decarboxylase as ECHDC1. We confirmed this identification by showing that recombinant mouse ECHDC1 has a substantial ethylmalonyl-CoA decarboxylase activity and a lower methylmalonyl-CoA decarboxylase activity but no malonyl-CoA decarboxylase or enoyl-CoA hydratase activity. Furthermore, ECHDC1-specific siRNAs decreased the ethylmalonyl-CoA decarboxylase activity in human cells and increased the formation of ethylmalonate, most particularly in cells incubated with butyrate. These findings indicate that ethylmalonyl-CoA decarboxylase may correct a side activity of acetyl-CoA carboxylase and suggest that its mutation may be involved in the development of certain forms of ethylmalonic aciduria. PMID:22016388

Linster, Carole L.; Noël, Gaëtane; Stroobant, Vincent; Vertommen, Didier; Vincent, Marie-Françoise; Bommer, Guido T.; Veiga-da-Cunha, Maria; Van Schaftingen, Emile

2011-01-01

440

Glycosylated linkers in multimodular lignocellulose-degrading enzymes dynamically bind to cellulose  

PubMed Central

Plant cell-wall polysaccharides represent a vast source of food in nature. To depolymerize polysaccharides to soluble sugars, many organisms use multifunctional enzyme mixtures consisting of glycoside hydrolases, lytic polysaccharide mono-oxygenases, polysaccharide lyases, and carbohydrate esterases, as well as accessory, redox-active enzymes for lignin depolymerization. Many of these enzymes that degrade lignocellulose are multimodular with carbohydrate-binding modules (CBMs) and catalytic domains connected by flexible, glycosylated linkers. These linkers have long been thought to simply serve as a tether between structured domains or to act in an inchworm-like fashion during catalytic action. To examine linker function, we performed molecular dynamics (MD) simulations of the Trichoderma reesei Family 6 and Family 7 cellobiohydrolases (TrCel6A and TrCel7A, respectively) bound to cellulose. During these simulations, the glycosylated linkers bind directly to cellulose, suggesting a previously unknown role in enzyme action. The prediction from the MD simulations was examined experimentally by measuring the binding affinity of the Cel7A CBM and the natively glycosylated Cel7A CBM-linker. On crystalline cellulose, the glycosylated linker enhances the binding affinity over the CBM alone by an order of magnitude. The MD simulations before and after binding of the linker also suggest that the bound linker may affect enzyme action due to significant damping in the enzyme fluctuations. Together, these results suggest that glycosylated linkers in carbohydrate-active enzymes, which are intrinsically disordered proteins in solution, aid in dynamic binding during the enzymatic deconstruction of plant cell walls. PMID:23959893

Payne, Christina M.; Resch, Michael G.; Chen, Liqun; Crowley, Michael F.; Himmel, Michael E.; Taylor, Larry E.; Sandgren, Mats; Stĺhlberg, Jerry; Stals, Ingeborg; Tan, Zhongping; Beckham, Gregg T.

2013-01-01

441

Glycosylated linkers in multimodular lignocellulose-degrading enzymes dynamically bind to cellulose.  

PubMed

Plant cell-wall polysaccharides represent a vast source of food in nature. To depolymerize polysaccharides to soluble sugars, many organisms use multifunctional enzyme mixtures consisting of glycoside hydrolases, lytic polysaccharide mono-oxygenases, polysaccharide lyases, and carbohydrate esterases, as well as accessory, redox-active enzymes for lignin depolymerization. Many of these enzymes that degrade lignocellulose are multimodular with carbohydrate-binding modules (CBMs) and catalytic domains connected by flexible, glycosylated linkers. These linkers have long been thought to simply serve as a tether between structured domains or to act in an inchworm-like fashion during catalytic action. To examine linker function, we performed molecular dynamics (MD) simulations of the Trichoderma reesei Family 6 and Family 7 cellobiohydrolases (TrCel6A and TrCel7A, respectively) bound to cellulose. During these simulations, the glycosylated linkers bind directly to cellulose, suggesting a previously unknown role in enzyme action. The prediction from the MD simulations was examined experimentally by measuring the binding affinity of the Cel7A CBM and the natively glycosylated Cel7A CBM-linker. On crystalline cellulose, the glycosylated linker enhances the binding affinity over the CBM alone by an order of magnitude. The MD simulations before and after binding of the linker also suggest that the bound linker may affect enzyme action due to significant damping in the enzyme fluctuations. Together, these results suggest that glycosylated linkers in carbohydrate-active enzymes, which are intrinsically disordered proteins in solution, aid in dynamic binding during the enzymatic deconstruction of plant cell walls. PMID:23959893

Payne, Christina M; Resch, Michael G; Chen, Liqun; Crowley, Michael F; Himmel, Michael E; Taylor, Larry E; Sandgren, Mats; Stĺhlberg, Jerry; Stals, Ingeborg; Tan, Zhongping; Beckham, Gregg T

2013-09-01

442

Catalytic Efficiency of Enzymes: A Theoretical Analysis  

PubMed Central

This brief review analyzes the underlying physical principles of enzyme catalysis, with an emphasis on the role of equilibrium enzyme motions and conformational sampling. The concepts are developed in the context of three representative systems, namely dihydrofolate reductase, ketosteroid isomerase, and soybean lipoxygenase. All of these reactions involve hydrogen transfer, but many of the concepts discussed are more generally applicable. The factors that are analyzed in this review include hydrogen tunneling, proton donor-acceptor motion, hydrogen bonding, pKa shifting, electrostatics, preorganization, reorganization, and conformational motions. The rate constant for the chemical step is determined primarily by the free energy barrier, which is related to the probability of sampling configurations conducive to the chemical reaction. According to this perspective, stochastic thermal motions lead to equilibrium conformational changes in the enzyme and ligands that result in configurations favorable to the breaking and forming of chemical bonds. For proton, hydride, and proton-coupled electron transfer reactions, typically the donor and acceptor become closer to facilitate the transfer. The impact of mutations on the catalytic rate constants can be explained in terms of the factors enumerated above. In particular, distal mutations can alter the conformational motions of the enzyme and therefore the probability of sampling configurations conducive to the chemical reaction. Methods such as vibrational Stark spectroscopy, in which environmentally sensitive probes are introduced site-specifically in the enzyme, provide further insight into these aspects of enzyme catalysis through a combination of experiments and theoretical calculations. PMID:23240765

Hammes-Schiffer, Sharon

2012-01-01

443

Sortase enzymes in Gram-positive bacteria  

PubMed Central

Summary In Gram-positive bacteria proteins are displayed on the cell surface using sortase enzymes. These cysteine transpeptidases join proteins bearing an appropriate sorting signal to strategically positioned amino groups on the cell surface. Working alone, or in concert with other enzymes, sortases either attach proteins to the cross-bridge peptide of the cell wall or they link proteins together to form pili. Because surface proteins play a fundamental role in microbial physiology and are frequently virulence factors, sortase enzymes have been intensely studied since their discovery a little more than a decade ago. Based on their primary sequences and functions sortases can be partitioned into distinct families called class A to F enzymes. Most bacteria elaborate their surfaces using more than one type of sortase that function non-redundantly by recognizing unique sorting signals within their protein substrates. Here we review what is known about the functions of these enzymes and the molecular basis of catalysis. Particular emphasis is placed on ‘pilin’ specific class C sortases that construct structurally complex pili. Exciting new data have revealed that these enzymes are amazingly promiscuous in the substrates that they can employ and that there is a startling degree of diversity in their mechanism of action. We also review recent data that suggest that sortases are targeted to specific sites on the cell surface where they work with other sortases and accessory factors to properly function. PMID:22026821

Spirig, Thomas; Weiner, Ethan M.; Clubb, Robert T.

2013-01-01

444

Enzyme-based antifouling coatings: a review.  

PubMed

A systematic overview is presented of the literature that reports the antifouling (AF) protection of underwater structures via the action of enzymes. The overall aim of this review is to assess the state of the art of enzymatic AF technology, and to highlight the obstacles that have to be overcome for successful development of enzymatic AF coatings. The approaches described in the literature are divided into direct and indirect enzymatic AF, depending on the intended action of the enzymes. Direct antifouling is used when the enzymes themselves are active antifoulants. Indirect antifouling refers to the use of enzymes to release an active biocide with AF activity. For direct AF, several patents have been granted, and a commercial product has been launched. However, the achievement of an efficient broad-spectrum AF coating based on a single or a few enzymes has not yet been achieved. An indirect AF coating is not yet available commercially. The technology is mainly limited by the instability of substrate supply, whether the substrates are found in the surrounding seawater or in the coating itself. Legislative issues regarding which part(s) of an enzyme system should be regarded as biocidal for product registration purposes are also considered. The above question currently remains unanswered for technologies utilising indirect enzymatic AF. PMID:17852071

Olsen, S M; Pedersen, L T; Laursen, M H; Kiil, S; Dam-Johansen, K

2007-01-01

445

Dietary modulation of thymic enzymes.  

PubMed

Malnutrition is a complex syndrome caused by an inadequate intake of energy, protein, minerals and vitamins which affects the immune system. Nutritional imbalances, present in children with energy-protein malnutrition and infections, make defining the specific effects of each of them on the thymus difficult. For this reason, it is necessary to design an experimental model in animals that could define a single variable. As the thymus atrophy described in humans is similar to that observed in murines, a rat experimental model makes the extrapolation to man possible. Some authors suggest that the activity of Adenosine Deaminase (ADA) and Purine Nucleoside Phosphorylase (PNP)--involved in purine metabolism--have an influence on T lymphocyte development and the immune system, due to intracellular accumulation of toxic levels of deoxynucleotides. Studies in our group, performed in an experimental model on Wistar growing rats, have demonstrated that protein deficiency or imbalance in the profile of essential amino acids in the diet, produce loss of thymus weight, reduction in the number of thymocytes, a diminished proportion of T cells presenting the W3/13 antigenic determinant and DNA content with concomitant increase in cell size, and the proportion of immature T cells and activity of ADA and PNP, without modifying the activity of 5´Nucleotidase in the thymus. It is important to point out that there were neither differences in energy intake between experimental groups and their controls, nor clinical symptoms of deficiency of other nutrients. The increase in these thymic enzyme activities was an alternative mechanism to avoid the accumulation of high levels of deoxynucleotides, which would be toxic for T lymphocytes. On the other hand, the administration of a recovery diet, with a high amount of high quality protein, was able to reverse the mentioned effects. The quick reply of Adenosine Deaminase to nutritional disorders and the following nutritional recovery, points out to this determination as a potential functional marker of nutritional status. Some authors have demonstrated an increase in ADA activity, in serum and other biological fluids in patients with various diseases involving defense mechanisms. According to these findings, it could be inferred that ADA activity in serum would follow the same behavior as observed in a rat thymus. So, we have analyzed if its determination could be considered a functional biochemical parameter in populations at nutritional risk. We analyzed the serum ADA activity in groups of individuals with altered nutritional status evaluated through different markers--young adult patients with Nervous Anorexia, overweight or obese school children, children suffering cystic fibrosis. The results show a statistically significant increase in the ADA activity in all groups, with respect to their healthy controls--same age range and socio economic status. The results obtained to date suggest the importance of including the determination of serum Adenosine Deaminase activity in the biochemical evaluation of the nutritional status, as a functional marker related to defense mechanisms. PMID:25229687

Susana, Feliu María; Paula, Perris; Slobodianik, Nora

2014-01-01

446

The iron–sulfur cluster in the l-serine dehydratase TdcG from Escherichia coli is required for enzyme activity  

Microsoft Academic Search

The anaerobically inducible l-serine dehydratase, TdcG, from Escherichia coli was characterized. Based on UV–visible spectroscopy, iron and labile sulfide analyses, the homodimeric enzyme is proposed to have two oxygen-labile [4Fe–4S]2+ clusters. Anaerobically isolated dimeric TdcG had a kcat of 544 s?1 and an apparent KM for l-serine of 4.8 mM. l-threonine did not act as a substrate for the enzyme.

Julia D. Burman; Roger L. Harris; Katherine A. Hauton; David M. Lawson; R. Gary Sawers

2004-01-01

447

78 FR 17176 - Federal Acquisition Regulation; Defense Base Act  

Federal Register 2010, 2011, 2012, 2013, 2014

...Federal Acquisition Regulation; Defense Base Act AGENCIES: Department of Defense...Compensation Act as extended by the Defense Base Act. DATES: Interested parties should...Compensation Act as extended by the Defense Base Act. II. Discussion and Analysis...

2013-03-20

448

George Washington's Acts of Congress  

NSDL National Science Digital Library

George Washington's personal copy of the Laws of the United States, First Session 1789 has returned from a whirlwind tour of the Presidential Libraries and has taken up permanent residence at Mount Vernon. This historic publication, also known as the Acts of Congress, offers a rare glimpse into the establishment of the American government. On this site, visitors can look over a photo gallery featuring more than a dozen images of this rare item, complete with Washington's own annotations. The site offers insights into Washington's thoughts about the presidency, his own role as chief executive, and much more. A pamphlet on the traveling exhibition and Teacher Resources are also available.

449

Fast-acting valve actuator  

DOEpatents

A fast-acting valve actuator utilizes a spring driven pneumatically loaded piston to drive a valve gate. Rapid exhaust of pressurized gas from the pneumatically loaded side of the piston facilitates an extremely rapid piston stroke. A flexible selector diaphragm opens and closes an exhaust port in response to pressure differentials created by energizing and de-energizing a solenoid which controls the pneumatic input to the actuator as well as selectively providing a venting action to one side of the selector diaphragm.

Cho, Nakwon (Knoxville, TN)

1980-01-01

450

Hemolytic anemias due to erythrocyte enzyme deficiencies.  

PubMed

Red blood cells can only fulfil their functions over the normal period of approximately 120 days with 1.7 x 10(5) circulatory cycles efficiently if they withstand external and internal loads. This requires ATP and redox equivalents, which have to be permanently regenerated by the energy and redox metabolism. These pathways are necessary to maintain the biconcave shape of the cells, their specific intracellular cation concentrations, the reduced state of hemoglobin with a divalent iron and the sulfhydryl groups of enzymes, glutathione and membrane components. If an enzyme deficiency of one of these metabolic pathways limits the ATP and/or NADPH production, distinct membrane alterations result causing a removal of the damaged cells by the monocyte-macrophage system. Most metabolic needs of erythrocytes are covered by glycolysis, the oxidative pentose phosphate pathway (OPPP), the glutathione cycle, nucleotide metabolism and MetHb reductase. Hereditary enzyme deficiencies of all these pathways have been identified; those that cause non-spherocytic hemolytic anemia are listed in Table 4. Their frequencies differ markedly both with respect to the affected enzyme and geographic distribution. Glucose-6-phosphate dehydrogenase enzymopathies (G6PD) are with more than 400 million cases by far the most common deficiency. The highest gene frequency has been found with 0.7 among Kurdish Jews. G6PD deficiencies are furthermore prevalent with frequencies of about 0.1 among Africans, Black Americans, and populations of Mediterranean countries and South East Asia. In Middle and Northern Europe the frequency of G6PD is much lower, and with approximately 0.0005, comparable with the frequency of pyruvate kinase (PK) enzymopathies, the most frequent enzyme deficiency in glycolysis in this area (Luzzatto, 1987; Beutler and Kuhl, 1990). The relationship between the degree of enzyme deficiency and the extent of metabolic dysfunction in red blood cells and other tissues depend on several factors: on the importance of the affected enzyme; its expression rate; the stability of the mutant enzyme against proteolytic degradation and functional abnormalities; the possibility to compensate the deficiency by an overexpression of the corresponding isoenzyme or by the use of an alternative metabolic pathway. Difficulties in estimating the quantitative degree of disorder in severe cases are due to the fact that these populations contain many reticulocytes, which generally have higher enzyme activities and concentrations of intermediates than erythrocytes. An alternative approach to predict metabolic changes is the analysis by mathematical modeling. Mathematical modeling of the main metabolic pathways of human erythrocytes has reached an advanced level (Rapoport et al., 1976; Holzhütter et al., 1985; Schuster et al., 1988). Models have been successfully employed to describe stationary and time-dependent metabolic states of the cell under normal conditions as well as in the presence of enzyme deficiencies. Figure 5 shows computational results of erythrocyte enzyme deficiencies. This analysis is based on the comprehensive mathematical model of the energy and redox metabolism for human erythrocyte presented in Fig. 6. Stationary states of the cell metabolism have been calculated by varying the activity of each of the participating enzymes by several orders of magnitude. To predict consequences of enzyme deficiencies a performance function has been introduced (Schuster and Holzhütter, 1995). It takes into account the homeostasis of three essential metabolic variables: the energetic state (ATP), the reductive capacity (reduced glutathione) and the osmotic state. From the data given in Fig. 5 one can conclude that generally the metabolic impairment resulting in deficiencies occurs earlier for enzymes with high control coefficients than for those catalyzing equilibrium reactions. On the other hand the flux curves of latter enzymes decrease more steeply below a critica PMID:8813716

Jacobasch, G; Rapoport, S M

1996-04-01

451

7 CFR 905.2 - Act.  

Code of Federal Regulations, 2013 CFR

...AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE ORANGES, GRAPEFRUIT, TANGERINES, AND TANGELOS GROWN IN FLORIDA Order Regulating Handling Definitions § 905.2 Act. Act...

2013-01-01

452

7 CFR 905.2 - Act.  

Code of Federal Regulations, 2014 CFR

...AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE ORANGES, GRAPEFRUIT, TANGERINES, AND TANGELOS GROWN IN FLORIDA Order Regulating Handling Definitions § 905.2 Act. Act...

2014-01-01

453

The Equality Act 2010 and mental health.  

PubMed

One aim of the Equality Act 2010 is to protect people with disabilities and prevent disability discrimination. We review the key provisions of the Act relevant to disability discrimination with respect to mental illness. PMID:22383764

Lockwood, Graeme; Henderson, Claire; Thornicroft, Graham

2012-03-01

454

75 FR 79278 - Community Reinvestment Act Regulations  

Federal Register 2010, 2011, 2012, 2013, 2014

...OTS-2010-0031] RIN 1550-AC42 Community Reinvestment Act Regulations AGENCIES...revisions to our rules implementing the Community Reinvestment Act (CRA). The agencies are revising the term ``community development'' to include...

2010-12-20

455

75 FR 36016 - Community Reinvestment Act Regulations  

Federal Register 2010, 2011, 2012, 2013, 2014

...OTS-2010-0017] RIN 1550-AC42 Community Reinvestment Act Regulations AGENCIES...provisions of our rules implementing the Community Reinvestment Act (CRA). The agencies propose to revise the term ``community development'' to include...

2010-06-24

456

77 FR 42175 - Securities Act Industry Guides  

Federal Register 2010, 2011, 2012, 2013, 2014

...Release Nos. 33-9337; 34-67432] Securities Act Industry Guides AGENCY: Securities and Exchange Commission. ACTION: Technical...Industry Guide 7''), of the Securities Act of 1933 Industry Guides (``Industry...

2012-07-18

457

Family Educational Rights and Privacy Act (FERPA)  

E-print Network

Practices · Tools and Resources FERPA Overview #12;Family Educational Rights and Privacy Act of 1974 · FERPAFamily Educational Rights and Privacy Act (FERPA) An Overview Bart Quinet University Registrar Vanderbilt University #12;· Background · Key Concepts · Annual Notification · Education Records · Public vs

Bordenstein, Seth

458

47 CFR 32.4 - Communications Act.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Communications Act. 32.4 Section 32.4 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON...COMPANIES Preface § 32.4 Communications Act. Attention is...

2010-10-01

459

47 CFR 32.4 - Communications Act.  

Code of Federal Regulations, 2011 CFR

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2011-10-01

460

47 CFR 32.4 - Communications Act.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Communications Act. 32.4 Section 32.4 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON...COMPANIES Preface § 32.4 Communications Act. Attention is...

2014-10-01

461

78 FR 21419 - Sunshine Act Meetings  

Federal Register 2010, 2011, 2012, 2013, 2014

...regarding future Management process reports 7. Public...act on other business 9. Consider...appropriations process Carol Bergman...Discussion with Management regarding process and timetable...act on other business 10....

2013-04-10

462

Estuaries and Clean Water Act of 2000  

NSDL National Science Digital Library

The Office of Water at the Environmental Protection Agency has posted online this document on the new Estuaries and Clean Water Act of 2000. Available in .pdf format, the document summarizes the Act, which emphasizes restoration of estuary habitat.

463

77 FR 57013 - Privacy Act; Implementation  

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...Act; Implementation AGENCY: Defense Intelligence Agency, DoD. ACTION: Direct final rule...SUMMARY: The Defense Intelligence Agency is updating the Defense Intelligence Agency Privacy Act Program, by...

2012-09-17

464

7 CFR 65.100 - Act.  

Code of Federal Regulations, 2013 CFR

...MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) COUNTRY OF ORIGIN LABELING OF BEEF, PORK, LAMB, CHICKEN, GOAT MEAT, PERISHABLE AGRICULTURAL COMMODITIES, MACADAMIA NUTS, PECANS, PEANUTS, AND GINSENG General Provisions...

2013-01-01

465

7 CFR 65.100 - Act.  

Code of Federal Regulations, 2012 CFR

...MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) COUNTRY OF ORIGIN LABELING OF BEEF, PORK, LAMB, CHICKEN, GOAT MEAT, PERISHABLE AGRICULTURAL COMMODITIES, MACADAMIA NUTS, PECANS, PEANUTS, AND GINSENG General Provisions...

2012-01-01

466

7 CFR 65.100 - Act.  

Code of Federal Regulations, 2014 CFR

...MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) COUNTRY OF ORIGIN LABELING OF BEEF, PORK, LAMB, CHICKEN, GOAT MEAT, PERISHABLE AGRICULTURAL COMMODITIES, MACADAMIA NUTS, PECANS, PEANUTS, AND GINSENG General Provisions...

2014-01-01

467

Clean Air Act Amendments of 1990  

E-print Network

Congress is currently debating amendments to the Clean Air Act which would strengthen and enhance the current Clean Air Act. The bill would guarantee a reduction of 10 million tons of sulfur dioxide from 1980 levels; would sharply reduce pollutants...

Hanneschlager, R. E.

468

78 FR 36279 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013, 2014

...Privacy and Civil Liberties Oversight Board will meet in closed session to discuss classified information pertaining to the PRISM-related activities and the Foreign Intelligence Surveillance Act. The Government in the Sunshine Act, 5 U.S.C....

2013-06-17

469

7 CFR 1219.1 - Act.  

Code of Federal Regulations, 2013 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order...1219.1 Act. Act means the Hass Avocado Promotion, Research, and Information...

2013-01-01

470

7 CFR 1219.1 - Act.  

Code of Federal Regulations, 2011 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order...1219.1 Act. Act means the Hass Avocado Promotion, Research, and Information...

2011-01-01

471

7 CFR 1219.1 - Act.  

Code of Federal Regulations, 2010 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order...1219.1 Act. Act means the Hass Avocado Promotion, Research, and Information...

2010-01-01

472

7 CFR 1219.1 - Act.  

Code of Federal Regulations, 2012 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order...1219.1 Act. Act means the Hass Avocado Promotion, Research, and Information...

2012-01-01

473

7 CFR 1219.1 - Act.  

Code of Federal Regulations, 2014 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order...1219.1 Act. Act means the Hass Avocado Promotion, Research, and Information...

2014-01-01

474

76 FR 20986 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013, 2014

...supervision, corporate and resolution activities. In calling the meeting, the Board determined, on motion of Director John E. Bowman (Acting Director, Office of Thrift Supervision), seconded by Director John G. Walsh (Acting Comptroller of the...

2011-04-14

475

75 FR 69444 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013, 2014

...supervision, corporate and resolution activities. In calling the meeting, the Board determined, on motion of Director John E. Bowman (Acting Director, Office of Thrift Supervision), seconded by Director John G. Walsh (Acting Comptroller of the...

2010-11-12

476

VIS/ACT: The next episode  

NASA Technical Reports Server (NTRS)

VIS/ACT is a multi-media educational system for aircrew coordination training (ACT). Students view video segments, answer questions that are adjusted to individual performance, and engage in related activities. Although the system puts the student in a reactive critiquing role, it has proved effective in improving performance on active targeted ACT skills, in group simulation tasks. VIS/ACT itself is the product of coordination among three Navy agencies.

Maney, Tucker; Hamburger, Henry

1993-01-01

477

Geometric and electronic structure contributions to function in non-heme iron enzymes.  

PubMed

Mononuclear non-heme Fe (NHFe) enzymes play key roles in DNA repair, the biosynthesis of antibiotics, the response to hypoxia, cancer therapy, and many other biological processes. These enzymes catalyze a diverse range of oxidation reactions, including hydroxylation, halogenation, ring closure, desaturation, and electrophilic aromatic substitution (EAS). Most of these enzymes use an Fe(II) site to activate dioxygen, but traditional spectroscopic methods have not allowed researchers to insightfully probe these ferrous active sites. We have developed a methodology that provides detailed geometric and electronic structure insights into these NHFe(II) active sites. Using these data, we have defined a general mechanistic strategy that many of these enzymes use: they control O2 activation (and limit autoxidation and self-hydroxylation) by allowing Fe(II) coordination unsaturation only in the presence of cosubstrates. Depending on the type of enzyme, O2 activation either involves a 2e(-) reduced Fe(III)-OOH intermediate or a 4e(-) reduced Fe(IV)?O intermediate. Nuclear resonance vibrational spectroscopy (NRVS) has provided the geometric structure of these intermediates, and magnetic circular dichroism (MCD) has defined the frontier molecular orbitals (FMOs), the electronic structure that controls reactivity. This Account emphasizes that experimental spectroscopy is critical in evaluating the results of electronic structure calculations. Therefore these data are a key mechanistic bridge between structure and reactivity. For the Fe(III)-OOH intermediates, the anticancer drug activated bleomycin (BLM) acts as the non-heme Fe analog of compound 0 in heme (e.g., P450) chemistry. However BLM shows different reactivity: the low-spin (LS) Fe(III)-OOH can directly abstract a H atom from DNA. The LS and high-spin (HS) Fe(III)-OOHs have fundamentally different transition states. The LS transition state goes through a hydroxyl radical, but the HS transition state is activated for EAS without O-O cleavage. This activation is important in one class of NHFe enzymes that utilizes a HS Fe(III)-OOH intermediate in dioxygenation. For Fe(IV)?O intermediates, the LS form has a ?-type FMO activated for attack perpendicular to the Fe-O bond. However, the HS form (present in the NHFe enzymes) has a ? FMO activated perpendicular to the Fe-O bond and a ? FMO positioned along the Fe-O bond. For the NHFe enzymes, the presence of ? and ? FMOs enables enzymatic control in determining the type of reactivity: EAS or H-atom extraction for one substrate with different enzymes and halogenation or hydroxylation for one enzyme with different substrates. PMID:24070107

Solomon, Edward I; Light, Kenneth M; Liu, Lei V; Srnec, Martin; Wong, Shaun D

2013-11-19

478

Endangered Species Act Biennial Report to  

E-print Network

Endangered Species Act Biennial Report to Congress October 1, 1996 - September 30, 1998 Prepared by Fisheries Service Office of Protected Resources #12;Endangered Species Act Biennial Report to Congress Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Status Discussions for Species Listed under the Endangered Species Act of 1973. . . . . . . . 38

479

Endangered Species Act Biennial Report to  

E-print Network

Endangered Species Act Biennial Report to Congress on the Status of Recovery Programs July for species listed under section 4 of the Endangered Species Act (ESA). Recovery plans for many and implement recovery plans for species listed under section 4 of the Endangered Species Act (ESA). Recovery

480

AMENDMENTS TO THE MEMORIAL UNIVERSITY PENSIONS ACT  

E-print Network

AMENDMENTS TO THE MEMORIAL UNIVERSITY PENSIONS ACT SUMMARY INFORMATION The following summary information is provided in relation to a series of amendments to the Memorial University Pensions Act (the Act.mun.ca/humanres/about/2009_BILL_38.mht The various general categories of change to the Memorial University Pension Plan (the

deYoung, Brad

481

Academic Development Is a Creative Act  

ERIC Educational Resources Information Center

This paper argues that academic development is a creative act. Creative acts have potential to inspire, critique, inform and in many cases to change. The creativity literature identifies a number of core features of creative acts that assist in developing independent creative practitioners. Those features are observing, attending to relationships,…

Budge, Kylie; Clarke, Angela

2012-01-01

482

ACT Assessment Results, 1994: Summary Report. National.  

ERIC Educational Resources Information Center

This report presents information about the performance of the 1994 graduating seniors nationwide who took the ACT Assessment as juniors or seniors. Average scores are on the scale for the Enhanced ACT Assessment, which was introduced in 1989. It must be recalled that ACT-tested seniors may not be representative of the total population of…

American Coll. Testing Program, Iowa City, IA.

483

Women's Health and Cancer Rights Act  

MedlinePLUS

Women’s Health and Cancer Rights Act The Federal law The Women’s Health and Cancer Rights Act (WHCRA) helps protect many ... Services. Centers for Medicare and Medicaid Services. The Women’s Health & Cancer Rights Act. Accessed at www.cms.hhs. ...

484

FMLA: Family & Medical FLA: Family Leave Act  

E-print Network

FMLA: Family & Medical Leave Act FLA: Family Leave Act DVL: Domestic Violence Leave Faculty Sick Leave FCAL: Family Care Act Leave Parental Leave & Leave Without Salary Who is · Faculty (9 month calendar weeks during one academic year (26 calendar weeks if eligible for "Service Member Family Leave

Borenstein, Elhanan

485

A Formal Semantics for Proxy Communicative Acts  

Microsoft Academic Search

Mediation services are becoming increasingly important in multiagent systems. An agent that can act on behalf of another agent is one important example of mediation functionality commonly required. Within this paper, we define and analyze PROXY and PROXY-WEAK communicative acts that formally specify semantics for interacting with middle agents that provide proxy services. These two communicative acts are shown to

Marcus J. Huber; Sanjeev Kumar; Philip R. Cohen; David R. McGee; J.-J. C. Meyer; M. Tambe

2001-01-01

486

Shattering the Equal Pay Act's Glass Ceiling  

Microsoft Academic Search

This Article provides the first empirical and rhetorical analysis of all reported Equal Pay Act (EPA) federal appellate cases since the Act’s passage. This analysis shows that as women climb the occupational ladder, the manner in which many federal courts interpret the EPA imposes a wage glass ceiling, shutting out women in non-standardized jobs from its protection. This barrier is

Deborah Thompson Eisenberg

2010-01-01

487

New developments concerning the Equal Pay Act  

Microsoft Academic Search

Considers why a wage gap still exists between men and women, despite the introduction in the USA of the Equal Pay Act (EPA) in 1963 and the Civil Rights Act (Title VII) in 1964. Details the Equal Employment Opportunity Commission’s (EEOC’s) interpretations of the two Acts’ provisions relating to employment discrimination on the basis of gender, looking in particular at

Li Yun Chen; Brian H. Kleiner

1998-01-01

488

ACTS Satellite Telemammography Network Experiments  

NASA Technical Reports Server (NTRS)

The Satellite Networks and Architectures Branch of NASA's Glenn Research Center has developed and demonstrated several advanced satellite communications technologies through the Advanced Communications Technology Satellite (ACTS) program. One of these technologies is the implementation of a Satellite Telemammography Network (STN) encompassing NASA Glenn, the Cleveland Clinic Foundation. the University of Virginia, and the Ashtabula County Medical Center. This paper will present a look at the STN from its beginnings to the impact it may have on future telemedicine applications. Results obtained using the experimental ACTS satellite demonstrate the feasibility of Satellite Telemammography. These results have improved teleradiology processes and mammography image manipulation, and enabled advances in remote screening methodologies. Future implementation of satellite telemammography using next generation commercial satellite networks will be explored. In addition, the technical aspects of the project will be discussed, in particular how the project has evolved from using NASA developed hardware and software to commercial off the shelf (COTS) products. Development of asymmetrical link technologies was an outcome of this work. Improvements in the display of digital mammographic images, better understanding of end-to-end system requirements, and advances in radiological image compression were achieved as a result of the research. Finally, rigorous clinical medical studies are required for new technologies such as digital satellite telemammography to gain acceptance in the medical establishment. These experiments produced data that were useful in two key medical studies that addressed the diagnostic accuracy of compressed satellite transmitted digital mammography images. The results of these studies will also be discussed.

Kachmar, Brian A.; Kerczewski, Robert J.

2000-01-01

489

Tracing metabolic pathways from enzyme data.  

PubMed

The IUBMB Enzyme List is widely used by other databases as a source for avoiding ambiguity in the recognition of enzymes as catalytic entities. However, it was never designed for activities such as pathway tracing, which have become increasingly important in systems biology. This is because it often relies on generic or representative reactions to show the reactions catalysed by enzymes of wide specificity. It is necessary to go to databases such as BRENDA to find further, more detailed, information on what is known about the range of substrates for any particular enzyme. In order to provide a framework for tracing pathways involving any specific enzyme or metabolite, we have created a Reactions Database from the material in the Enzyme List. This allows reactions to be searched by substrate/product and pathways to be traced from any selected starting/seed substrate. An extensive synonym glossary allows searches by many of the alternative names, including accepted abbreviations, by which a chemical compound may be known. This database was necessary for the development of the application Reaction Explorer (http://www.reaction-explorer.org), which was written in REALbasic to search the Reactions Database and draw metabolic pathways from reactions selected by the user. Having input the name of the starting compound (the "seed"), the user is presented with a list of all reactions containing that compound and then selects the product of interest as the next point on the ensuing graph. The pathway diagram is then generated as the process iterates. A contextual menu is provided, which allows the user to (i) remove a compound from the graph, along with all associated links; (ii) search the reactions database again for additional reactions involving the compound and (iii) search for the compound within the Enzyme List. PMID:19563919

McDonald, Andrew G; Tipton, Keith F; Boyce, Sinéad

2009-09-01

490

The Bayh-Dole Act turns 30.  

PubMed

On 12 December 1980, in the waning days of the lame duck session of the 96th Congress, the U.S. Senate passed the University and Small Business Patent Procedures Act, now known as the Bayh-Dole Act, a seemingly obscure act that allowed universities to claim title to inventions that had been made with federal funding. It is unlikely that many present that day realized what a dramatic impact that act would have. Data clearly show that it played a critical role in rejuvenating the entire U.S. economic system, transforming it from a manufacturing base to an innovation base. Yet ironically, the act has passionate critics. PMID:20926832

Loise, Vicki; Stevens, Ashley J

2010-10-01

491

Thermophilic Fungi: Their Physiology and Enzymes  

PubMed Central

Thermophilic fungi are a small assemblage in mycota that have a minimum temperature of growth at or above 20°C and a maximum temperature of growth extending up to 60 to 62°C. As the only representatives of eukaryotic organisms that can grow at temperatures above 45°C, the thermophilic fungi are valuable experimental systems for investigations of mechanisms that allow growth at moderately high temperature yet limit their growth beyond 60 to 62°C. Although widespread in terrestrial habitats, they have remained underexplored compared to thermophilic species of eubacteria and archaea. However, thermophilic fungi are potential sources of enzymes with scientific and commercial interests. This review, for the first time, compiles information on the physiology and enzymes of thermophilic fungi. Thermophilic fungi can be grown in minimal media with metabolic rates and growth yields comparable to those of mesophilic fungi. Studies of their growth kinetics, respiration, mixed-substrate utilization, nutrient uptake, and protein breakdown rate have provided some basic information not only on thermophilic fungi but also on filamentous fungi in general. Some species have the ability to grow at ambient temperatures if cultures are initiated with germinated spores or mycelial inoculum or if a nutritionally rich medium is used. Thermophilic fungi have a powerful ability to degrade polysaccharide constituents of biomass. The properties of their enzymes show differences not only among species but also among strains of the same species. Their extracellular enzymes display temperature optima for activity that are close to or above the optimum temperature for the growth of organism and, in general, are more heat stable than those of the mesophilic fungi. Some extracellular enzymes from thermophilic fungi are being produced commercially, and a few others have commercial prospects. Genes of thermophilic fungi encoding lipase, protease, xylanase, and cellulase have been cloned and overexpressed in heterologous fungi, and pure crystalline proteins have been obtained for elucidation of the mechanisms of their intrinsic thermostability and catalysis. By contrast, the thermal stability of the few intracellular enzymes that have been purified is comparable to or, in some cases, lower than that of enzymes from the mesophilic fungi. Although rigorous data are lacking, it appears that eukaryotic thermophily involves several mechanisms of stabilization of enzymes or optimization of their activity, with different mechanisms operating for different enzymes. PMID:10974122

Maheshwari, Ramesh; Bharadwaj, Girish; Bhat, Mahalingeshwara K.

2000-01-01

492

The temperature response of fungal enzyme kinetics  

NASA Astrophysics Data System (ADS)

Extracellular enzymes produced and excreted by microbes mediate the decomposition of carbon (C), nitrogen (N), and phosphorus (P) -containing compounds in their environment. Climate change has the potential to alter the rate of decomposition especially in high latitude regions where stocks of recalcitrant, or long-lived, C are abundant. This project compares extracellular enzyme activity (EEA) across ten fungi strains within the model family Neurospora in order to assess the range of variation in temperature sensitivities of fungal enzyme Vmax and Km. Vmax values of most enzymes tested increased exponentially,which was hypothesized and consistant with thermodynamic principles. We also hypothesized that Neurospora strains would exhibit different EEA temperature sensitivities based on their native climate. We observed strain-dependent variation in enzyme temperature responses consistent with strain-specific adaptation to local conditions. Since fungi are the major decomposers of organic carbon in high-latitude ecosystems, an increase in EEA in-situ would result in higher carbon dioxide emissions. These findings suggest a shift in fungal processing of soil organic carbon and nutrients in response to changing climate.

Curran, M.; Lu, Y.; Taylor, J.; Allison, S. D.

2013-12-01

493

Salivary enzymes in peptic ulcer disease  

PubMed Central

Aim Peptic ulcer, the common disease of the upper gastro-intestinal tract, occurs in about 5–10% of the world's population. Therefore, diagnosis of trace disease progression with a noninvasive method is of prime importance in the field of healthcare research. The aim of this study was to evaluate the validity of salivary enzymes as noninvasive biomarkers for peptic ulcer. Materials and methods In practice, 34 peptic ulcer patients and 30 healthy subjects donated their un-stimulated saliva samples after 8 h of fasting. The activity of some selected enzymes was measured using appropriate enzymatic assay methods. Results The results indicated an overall alternation in enzymatic activity of saliva in patients suffering from peptic ulcer. Biological activity of a-amylase, peroxidase and lactate dehydrogenase, showed significantly higher values in almost all patients as compared to control subjects. Conclusions Based on the results of salivary enzyme activity, it was concluded that besides the influence of their peptic ulcer on enzyme activity of saliva, the considerably higher activity of a-amylase could also be related to the major role of the enzyme on physiological oxidative stress. PMID:25737890

Motamedi, Mojdeh; Mansour-Ghanaei, Fariborz; Sariri, Reyhaneh; Vesal, Mahmoud

2013-01-01

494

Type I restriction enzymes and their relatives  

PubMed Central

Type I restriction enzymes (REases) are large pentameric proteins with separate restriction (R), methylation (M) and DNA sequence-recognition (S) subunits. They were the first REases to be discovered and purified, but unlike the enormously useful Type II REases, they have yet to find a place in the enzymatic toolbox of molecular biologists. Type I enzymes have been difficult to characterize, but this is changing as genome analysis reveals their genes, and methylome analysis reveals their recognition sequences. Several Type I REases have been studied in detail and what has been learned about them invites greater attention. In this article, we discuss aspects of the biochemistry, biology and regulation of Type I REases, and of the mechanisms that bacteriophages and plasmids have evolved to evade them. Type I REases have a remarkable ability to change sequence specificity by domain shuffling and rearrangements. We summarize the classic experiments and observations that led to this discovery, and we discuss how this ability depends on the modular organizations of the enzymes and of their S subunits. Finally, we describe examples of Type II restriction–modification systems that have features in common with Type I enzymes, with emphasis on the varied Type IIG enzymes. PMID:24068554

Loenen, Wil A. M.; Dryden, David T. F.; Raleigh, Elisabeth A.; Wilson, Geoffrey G.

2014-01-01

495

From the Rehabilitation Act of 1973 (Section 504) to the Americans with Disabilities Act  

E-print Network

From the Rehabilitation Act of 1973 (Section 504) to the Americans with Disabilities Act Twenty publications and look for the report titled From the Rehabilitation Act of 1973 to the Americans with Disabilities Act Twenty-six Years Later. Edition: Update # 1: June 25, 1999 Report Procedure This report

Slatton, Clint

496

12 CFR 741.214 - Report of crime or catastrophic act and Bank Secrecy Act compliance.  

Code of Federal Regulations, 2010 CFR

...Banking 6 2010-01-01 2010-01-01 false Report of crime or catastrophic act and Bank Secrecy Act compliance. 741...Insured State-Chartered Credit Unions § 741.214 Report of crime or catastrophic act and Bank Secrecy Act compliance....

2010-01-01

497

36 CFR 51.101 - Did the 1998 Act repeal the 1965 Act?  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Did the 1998 Act repeal the 1965 Act? 51.101 Section 51.101 Parks, Forests...INTERIOR CONCESSION CONTRACTS The Effect of the 1998 Act's Repeal of the 1965 Act § 51.101 Did the...

2010-07-01

498

An amperometric enzyme biosensor for real-time measurements of cellobiohydrolase activity on insoluble cellulose.  

PubMed

An amperometric enzyme biosensor for continuous detection of cellobiose has been implemented as an enzyme assay for cellulases. We show that the initial kinetics for cellobiohydrolase I, Cel7A from Trichoderma reesei, acting on different types of cellulose substrates, semi-crystalline and amorphous, can be monitored directly and in real-time by an enzyme-modified electrode based on cellobiose dehydrogenase (CDH) from Phanerochaete chrysosporium (Pc). PcCDH was cross-linked and immobilized on the surface of a carbon paste electrode which contained a mediator, benzoquinone. An oxidation current of the reduced mediator, hydroquinone, produced by the CDH-catalyzed reaction with cellobiose, was recorded under constant-potential amperometry at +0.5 V (vs. Ag/AgCl). The CDH-biosensors showed high sensitivity (87.7 µA mM(-1) cm(-2)), low detection limit (25 nM), and fast response time (t(95%) ? 3 s) and this provided experimental access to the transient kinetics of cellobiohydrolases acting on insoluble cellulose. The response from the CDH-biosensor during enzymatic hydrolysis was corrected for the specificity of PcCDH for the ?-anomer of cello-oligosaccharides and the approach were validated against HPLC. It is suggested that quantitative, real-time data on pure insoluble cellulose substrates will be useful in attempts to probe the molecular mechanism underlying enzymatic hydrolysis of cellulose. PMID:22767376

Cruys-Bagger, Nicolaj; Ren, Guilin; Tatsumi, Hirosuke; Baumann, Martin J; Spodsberg, Nikolaj; Andersen, Heidi Delcomyn; Gorton, Lo; Borch, Kim; Westh, Peter

2012-12-01

499

ACTS: Technology Description and Results  

NASA Technical Reports Server (NTRS)

The ACTS Project was originated at NASA Glenn Research Center in the early 1980's to sponsor the development and application of technology that was intended to be used by the private sector. The program was formulated with the underlying philosophy of maintaining US leadership in satellite communications while focusing technology development for efficient use of the frequency spectrum. This report chronicles the execution and results of the program from the perspective of its technology managers, from inception through hardware and system development to on-orbit experiments and demonstrations of the technology. The first eight sections of the report discuss programmatic background, the specific satellite and ground terminal technology and the results generated by the program including industry relevance. A federally funded program of this type attracted strong advocates and adversaries and the resulting impact on the project schedule is also discussed. The last two sections are a list of useful acronyms and extensive references.

Gedney, Richard T.; Schertler, Ronald; Gargione, Frank

2000-01-01

500

Stratospheric Ozone: A Balancing Act  

NSDL National Science Digital Library

This activity demonstrates the concept of equilibrium as applied to a model system and to stratospheric ozone. Although the materials are easy to come by, this model set-up does require a fair amount of preparation. This can be done as a laboratory activity or as a classroom demonstration. A feature of this site is an animation that shows the depletion of ozone and the regeneration that causes the chlorine atom to act as a catalyst in the destruction of the ozone layer. The teacher's guide contains detailed background material, learning goals, alignment to national standards, grade level/time, details on materials and preparation, procedure, assessment ideas, and modifications for alternative learners.