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1

Functional characterization of alpha-glucan,water dikinase, the starch phosphorylating enzyme.  

PubMed Central

GWD (alpha-glucan,water dikinase) is the enzyme that catalyses the phosphorylation of starch by a dikinase-type reaction in which the beta-phosphate of ATP is transferred to either the C-6 or the C-3 position of the glycosyl residue of amylopectin. GWD shows similarity in both sequence and reaction mechanism to bacterial PPS (pyruvate,water dikinase) and PPDK (pyruvate,phosphate dikinase). Amino acid sequence alignments identified a conserved histidine residue located in the putative phosphohistidine domain of potato GWD. Site-directed mutagenesis of this histidine residue resulted in an inactive enzyme and loss of autophosphorylation. Native GWD is a homodimer and shows a strict requirement for the presence of alpha-1,6 branch points in its polyglucan substrate, and exhibits a sharp 20-fold increase in activity when the degree of polymerization is increased from 27.8 to 29.5. In spite of the high variability in the degree of starch phosphorylation, GWD proteins are ubiquitous in plants. The overall reaction mechanism of GWD is similar to that of PPS and PPDK, but the GWD family appears to have arisen after divergence of the plant kingdom. The nucleotide-binding domain of GWD exhibits a closer phylogenetic relationship to prokaryotic PPSs than to PPDKs. PMID:14525539

Mikkelsen, Rene; Baunsgaard, Lone; Blennow, Andreas

2004-01-01

2

ApuA, a multifunctional alpha-glucan-degrading enzyme of Streptococcus suis, mediates adhesion to porcine epithelium and mucus.  

PubMed

We have identified apuA in Streptococcus suis, which encodes a bifunctional amylopullulanase with conserved alpha-amylase and pullulanase substrate-binding domains and catalytic motifs. ApuA exhibited properties typical of a Gram-positive surface protein, with a putative signal sequence and LPKTGE cell-wall-anchoring motif. A recombinant protein containing the predicted N-terminal alpha-amylase domain of ApuA was shown to have alpha-(1,4) glycosidic activity. Additionally, an apuA mutant of S. suis lacked the pullulanase alpha-(1,6) glycosidic activity detected in a cell-surface protein extract of wild-type S. suis. ApuA was required for normal growth in complex medium containing pullulan as the major carbon source, suggesting that this enzyme plays a role in nutrient acquisition in vivo via the degradation of glycogen and food-derived starch in the nasopharyngeal and oral cavities. ApuA was shown to promote adhesion to porcine epithelium and mucus in vitro, highlighting a link between carbohydrate utilization and the ability of S. suis to colonize and infect the host. PMID:20522493

Ferrando, Maria Laura; Fuentes, Susana; de Greeff, Astrid; Smith, Hilde; Wells, Jerry M

2010-09-01

3

Structure-function relationships of glucansucrase and fructansucrase enzymes from lactic acid bacteria.  

PubMed

Lactic acid bacteria (LAB) employ sucrase-type enzymes to convert sucrose into homopolysaccharides consisting of either glucosyl units (glucans) or fructosyl units (fructans). The enzymes involved are labeled glucansucrases (GS) and fructansucrases (FS), respectively. The available molecular, biochemical, and structural information on sucrase genes and enzymes from various LAB and their fructan and alpha-glucan products is reviewed. The GS and FS enzymes are both glycoside hydrolase enzymes that act on the same substrate (sucrose) and catalyze (retaining) transglycosylation reactions that result in polysaccharide formation, but they possess completely different protein structures. GS enzymes (family GH70) are large multidomain proteins that occur exclusively in LAB. Their catalytic domain displays clear secondary-structure similarity with alpha-amylase enzymes (family GH13), with a predicted permuted (beta/alpha)(8) barrel structure for which detailed structural and mechanistic information is available. Emphasis now is on identification of residues and regions important for GS enzyme activity and product specificity (synthesis of alpha-glucans differing in glycosidic linkage type, degree and type of branching, glucan molecular mass, and solubility). FS enzymes (family GH68) occur in both gram-negative and gram-positive bacteria and synthesize beta-fructan polymers with either beta-(2-->6) (inulin) or beta-(2-->1) (levan) glycosidic bonds. Recently, the first high-resolution three-dimensional structures have become available for FS (levansucrase) proteins, revealing a rare five-bladed beta-propeller structure with a deep, negatively charged central pocket. Although these structures have provided detailed mechanistic insights, the structural features in FS enzymes dictating the synthesis of either beta-(2-->6) or beta-(2-->1) linkages, degree and type of branching, and fructan molecular mass remain to be identified. PMID:16524921

van Hijum, Sacha A F T; Kralj, Slavko; Ozimek, Lukasz K; Dijkhuizen, Lubbert; van Geel-Schutten, Ineke G H

2006-03-01

4

Selection acting directly on an enzyme polymorphism  

Microsoft Academic Search

A biochemical approach is utilised in the study of the maintenance of variation at the Adh locus in Drosophila melanogaster. There is a direct correlation between biochemical findings and the results of competition experiments. The relevance of these findings to the study of other enzyme polymorphisms is discussed.

Phillip Morgan

1975-01-01

5

Selection acting directly on an enzyme polymorphism.  

PubMed

A biochemical approach is utilised in the study of the maintenance of variation at the Adh locus in Drosophila melanogaster. There is a direct correlation between biochemical findings and the results of competition experiments. The relevance of these findings to the study of other enzyme polymorphisms is discussed. PMID:804462

Morgan, P

1975-02-01

6

Structure and function of enzymes acting on chitin and chitosan.  

PubMed

Enzymatic conversions of chitin and its soluble, partially deacetylated derivative chitosan are of great interest. Firstly, chitin metabolism is an important process in fungi, insects and crustaceans. Secondly, such enzymatic conversions may be used to transform an abundant biomass to useful products such as bioactive chito-oligosaccharides. Enzymes acting on chitin and chitosan are abundant in nature. Here we review current knowledge on the structure and function of enzymes involved in the conversion of these polymeric substrates: chitinases (glycoside hydrolase families 18 & 19), chitosanases (glycoside hydrolase families 8, 46, 75 & 80) and chitin deacetylases (carbohydrate esterase family 4). PMID:21415904

Eijsink, Vincent; Hoell, Ingunn; Vaaje-Kolstada, Gustav

2010-01-01

7

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 ...

8

Fumarate analogs act as allosteric inhibitors of the human mitochondrial NAD(P)+-dependent malic enzyme.  

PubMed

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

Hsieh, Ju-Yi; Liu, Jyung-Hurng; Yang, Pai-Chun; Lin, Chi-Li; Liu, Guang-Yaw; Hung, Hui-Chih

2014-01-01

9

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

10

A direct-acting fibrinolytic enzyme from the venom of Agkistrodon contortrix contortrix: effects on various components of the human blood coagulation and fibrinolysis systems.  

PubMed

A direct acting fibrinolytic enzyme (fibrolase) has been isolated from venom of the southern copperhead snake (Agkistrodon contortrix contortrix). Time-course experiments established that the venom enzyme cleaves primarily the A alpha-chain of human fibrinogen and fibrin between the Lys-413 and Leu-414 position. The B beta-chain is cleaved more slowly, while the gamma-chain is minimally affected. The cleavage pattern of fibrinogen and fibrin clearly varies from plasmin cleavage of the same molecules. The enzyme does not activate plasminogen or protein c and it is thus different from "Protac", a protein c activator isolated from the same venom. PMID:3232124

Retzios, A D; Markland, F S

1988-12-15

11

Biosynthesis of the immunosuppressants FK506, FK520, and rapamycin involves a previously undescribed family of enzymes acting on chorismate  

PubMed Central

The macrocyclic polyketides FK506, FK520, and rapamycin are potent immunosuppressants that prevent T-cell proliferation through initial binding to the immunophilin FKBP12. Analogs of these molecules are of considerable interest as therapeutics in both metastatic and inflammatory disease. For these polyketides the starter unit for chain assembly is (4R,5R)-4,5-dihydroxycyclohex-1-enecarboxylic acid derived from the shikimate pathway. We show here that the first committed step in its formation is hydrolysis of chorismate to form (4R,5R)-4,5-dihydroxycyclohexa-1,5-dienecarboxylic acid. This chorismatase activity is encoded by fkbO in the FK506 and FK520 biosynthetic gene clusters, and by rapK in the rapamycin gene cluster of Streptomyces hygroscopicus. Purified recombinant FkbO (from FK520) efficiently catalyzed the chorismatase reaction in vitro, as judged by HPLC-MS and NMR analysis. Complementation using fkbO from either the FK506 or the FK520 gene cluster of a strain of S. hygroscopicus specifically deleted in rapK (BIOT-4010) restored rapamycin production, as did supplementation with (4R,5R)-4,5-dihydroxycyclohexa-1,5-dienecarboxylic acid. Although BIOT-4010 produced no rapamycin, it did produce low levels of BC325, a rapamycin analog containing a 3-hydroxybenzoate starter unit. This led us to identify the rapK homolog hyg5 as encoding a chorismatase/3-hydroxybenzoate synthase. Similar enzymes in other bacteria include the product of the bra8 gene from the pathway to the terpenoid natural product brasilicardin. Expression of either hyg5 or bra8 in BIOT-4010 led to increased levels of BC325. Also, purified Hyg5 catalyzed the predicted conversion of chorismate into 3-hydroxybenzoate. FkbO, RapK, Hyg5, and Bra8 are thus founder members of a previously unrecognized family of enzymes acting on chorismate. PMID:21383123

Andexer, Jennifer N.; Kendrew, Steven G.; Nur-e-Alam, Mohammad; Lazos, Orestis; Foster, Teresa A.; Zimmermann, Anna-Sophie; Warneck, Tony D.; Suthar, Dipen; Coates, Nigel J.; Koehn, Frank E.; Skotnicki, Jerauld S.; Carter, Guy T.; Gregory, Matthew A.; Martin, Christine J.; Moss, Steven J.; Leadlay, Peter F.; Wilkinson, Barrie

2011-01-01

12

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

13

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.

14

Sustained 24-hour blockade of the renin-angiotensin system: A high dose of a long-acting blocker is as effective as a lower dose combined with an angiotensin-converting enzyme inhibitor  

Microsoft Academic Search

Whether a higher dose of a long-acting angiotensin II receptor blocker (ARB) can provide as much blockade of the renin-angiotensin system over a 24-hour period as the combination of an angiotensin-converting enzyme inhibitor and a lower dose of ARB has not been formally demonstrated so far. In this randomized double-blind study we investigated renin-angiotensin system blockade obtained with 3 doses

Christopher Hasler; Jürg Nussberger; Marc Maillard; Andrei Forclaz; Hans R. Brunner; Michel Burnier

2005-01-01

15

Identification of bioactivating enzymes involved in the hydrolysis of laninamivir octanoate, a long-acting neuraminidase inhibitor, in human pulmonary tissue.  

PubMed

Laninamivir octanoate (LO) is an octanoyl ester prodrug of the neuraminidase inhibitor laninamivir. After inhaled administration, LO exhibits clinical efficacy for both treatment and prophylaxis of influenza virus infection, resulting from hydrolytic bioactivation into its pharmacologically active metabolite laninamivir in the pulmonary tissue. In this study, we focused on the identification of LO-hydrolyzing enzymes from human pulmonary tissue extract using proteomic correlation profiling-a technology integration of traditional biochemistry and proteomics. In a single elution step by gel-filtration chromatography, LO-hydrolyzing activity was separated into two distinct peaks, designated as peak I and peak II. By mass spectrometry, 1160 and 1003 proteins were identified and quantitated for peak I and peak II, respectively, and enzyme candidates were ranked based on the correlation coefficient between the enzyme activity and the proteomic profiles. Among proteins with a high correlation value, S-formylglutathione hydrolase (esterase D; ESD) and acyl-protein thioesterase 1 (APT1) were selected as the most likely candidates for peak I and peak II, respectively, which was confirmed by LO-hydrolyzing activity of recombinant proteins. In the case of peak II, LO-hydrolyzing activity was completely inhibited by treatment with a specific APT1 inhibitor, palmostatin B. Moreover, immunohistochemical analysis revealed that both enzymes were mainly localized in the pulmonary epithelia, a primary site of influenza virus infection. These findings demonstrate that ESD and APT1 are key enzymes responsible for the bioactivation of LO in human pulmonary tissue. PMID:24682756

Koyama, Kumiko; Ogura, Yuji; Nakai, Daisuke; Watanabe, Mihoko; Munemasa, Toshiko; Oofune, Yuka; Kubota, Kazuishi; Shinagawa, Akira; Izumi, Takashi

2014-06-01

16

Pancreatic Enzymes  

MedlinePLUS

Pancreatic enzymes Ver esta página en español What are pancreatic enzymes? Pancreatic enzymes help break down fats, proteins and carbohydrates. A ... into the duodenum, daily. This fluid contains pancreatic enzymes to help with digestion and bicarbonate to neutralize ...

17

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

18

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.

School, Minerva D.

2011-10-03

19

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;); Karen Sprague (University of Oregon;); Will Goodwin (University of Oregon;); Sam Donovan (University of Oregon;); Vicki Chandler (University of Oregon;)

1998-01-01

20

Design acts  

E-print Network

What an architect does, designing, is a design act and not the making of an object, a design. A design act is an intentional act about built use. We give reasons for intentional acts and are responsible for knowing that ...

Saslaw, Ellen

1987-01-01

21

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

22

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.

Crumlish, Jane

2009-01-01

23

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.

School, Maryland V.

24

Enzyme Kinetics  

NSDL National Science Digital Library

This is a lesson from the Computational Biology for Biology Educators workshop series run by the National Computational Science Institute, with sponsorship from the Education Program of the International Supercomputing Conference and the National Science Foundation. The goal of these workshops is the integration of mathematics and computation into the undergraduate Biology classroom, and the integration of biological applications into the Mathematics and Computer Science classroom. Outline Biology background Putting enzymes in action with Agent Sheets Modeling enzymes as dynamic systems with Vensim Biology Background Enzymes accelerate specific molecular events catalytically Movie of MD simulation of HIV-1 protease with substrate There are three types of molecular events that underlie most enzymatic processes Association-dissociation Conformational rearrangement Bond making and breaking Some resources for demonstrating that life\\'s molecular machines are dynamic: Molecules in Motion Database of Macromolecular Movements DSMM - Database of Simulated Molecular Motions The Michaelis-Menten model is a ...

Krause

2008-10-31

25

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

26

Engineering enzymes  

PubMed Central

Fundamental research into bioinorganic catalysis of the kind presented at this Faraday Discussion has the potential to turn inspiration drawn from impressive natural energy and chemical transformations into artificial catalyst constructions useful to mankind. Creating bio-inspired artificial constructions requires a level of understanding well beyond simple description of structures and mechanisms of natural enzymes. To be useful, such description must be augmented by a practical sense of structural and energetic engineering tolerances of the mechanism. Significant barriers to achieving an engineering understanding of enzyme mechanisms arise from natural protein complexity. In certain cases we can surmount these barriers to understanding, such as natural electron tunneling, coupling of electron tunneling to light capture and proton exchange as well as simpler bond breaking redox catalysis. Hope for similar solutions of more complex bioinorganic enzymes is indicated in several papers presented in this Discussion. Armed with an engineering understanding of mechanism, the current serious frustrations to successful creation of functional artificial proteins that are rooted in protein complexity can fall away. Here we discuss the genetic and biological roots of protein complexity and show how to dodge and minimize the effects of complexity. In the best-understood cases, artificial enzymes can be designed from scratch using the simplest of protein scaffolds. PMID:21322497

Moser, Christopher C.

2014-01-01

27

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

28

Enzymes as Chemotherapeutic Agents Ronald T. Raines  

E-print Network

enzymic drugs act by blocking the flow of biochemical information. Here, I report on the ability the best character- ized of all enzymes [1]. RNase A was studied extensively during the 1960s and 1970s when the Nobel Prize in chemistry was awarded jointly to Stanford Moore, William Stein, and Christian

Raines, Ronald T.

29

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

30

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

31

ACT Test  

MedlinePLUS

... available for download at http://www.massgeneral.org/pathology/assets/poct/MGH-Medtronic-ACT-Plus-procedure.pdf ... May 29). Activated Clotting Time. Massachusetts General Hospital Pathology Service [On-line information]. Available online through http:// ...

32

Enzyme Immobilization Alternatives for the Enzyme Alarm.  

National Technical Information Service (NTIS)

The objective of this research program was to investigate new methods for immobilizing the enzyme, acetylcholinesterase, on selected supports suitable for use in enzyme alarms. Various coupling procedures were developed for glass, nylon and urethane suppo...

H. W. Levin, E. S. Erenrich

1976-01-01

33

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); Megan L. Matthews (Pennsylvania State University;Department of Chemistry)

2010-03-12

34

AMINOHYDROLASES ACTING ON ADENINE, ADENOSINE AND THEIR DERIVATIVES  

Microsoft Academic Search

Background: Adenine and adenosine-acting aminohydrolases are important groups of enzymes responsible for the metabolic salvage of purine compounds. Several subclasses of these enzymes have been described and given current knowledge of the full genome sequences of many organisms, it is possible to identify genes encoding these enzymes and group them according to their primary structure. Methods and Results: This article

Hana Pospisilova; Ivo Frebort

35

Enzyme Immobilization Alternatives for the Enzyme Alarm.  

National Technical Information Service (NTIS)

The research concerns the study of alternative processes for coupling the cholinesterase enzyme to various supports in order to achieve enzyme-support product(s) which can be produced in large quantities, stored and then provide at least 12 hours of relia...

H. W. Levin, E. S. Erenrich

1975-01-01

36

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

37

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

38

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

39

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

40

Enzymes in detergents  

Microsoft Academic Search

Factors affecting the performance of proteolytic and amylolytic enzymes in an anionic and nonionic detergent formulation have\\u000a been studied using stain removal from EMPA blood-milk-ink and cocoa-milk-sugar soil test cloths as a measure of enzyme activity\\u000a in the detergent solution. Factors considered include enzyme concentration, and temperature and pH of the wash solution. Results\\u000a on stability of these enzymes in

R. L. Liss; R. P. Langguth

1969-01-01

41

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.

Committee., International U.

1998-01-01

42

Extracellular Enzymes Lab Biochemistry  

E-print Network

Extracellular Enzymes Lab Biochemistry · All organisms convert small organic compounds by enzymes. Glucose (C6) Pentose (C5) Triose (C3) Pyruvate (C3) AcetylCoA (C2) Citrate (C6) Oxoglutarate (C5 Cycle Pentose Phosphate PathwayEMP Pathway #12;More Complete Metabolic Network TOP #12;#12;Enzymes

Vallino, Joseph J.

43

Extracellular Enzymes Lab Biochemistry  

E-print Network

Extracellular Enzymes Lab Biochemistry · All organisms convert small organic compounds shown here: All of these reactions, of which there are more than 1000, are catalyzed by enzymes. Glucose Phosphate PathwayEMP Pathway #12;Amino Acids #12;More Complete Metabolic Network TOP #12;#12;Enzymes

Vallino, Joseph J.

44

Enzymes from extremophiles  

Microsoft Academic Search

The industrial application of enzymes that can withstand harsh conditions has greatly increased over the past decade. This is mainly a result of the discovery of novel enzymes from extremophilic microorganisms. Recent advances in the study of extremozymes point to the acceleration of this trend. In particular, enzymes from thermophilic organisms have found the most practical commercial use to date

David C Demirjian; Francisco Mor??s-Varas; Constance S Cassidy

2001-01-01

45

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

46

Self-powered enzyme micropumps.  

PubMed

Non-mechanical nano- and microscale pumps that function without the aid of an external power source and provide precise control over the flow rate in response to specific signals are needed for the development of new autonomous nano- and microscale systems. Here we show that surface-immobilized enzymes that are independent of adenosine triphosphate function as self-powered micropumps in the presence of their respective substrates. In the four cases studied (catalase, lipase, urease and glucose oxidase), the flow is driven by a gradient in fluid density generated by the enzymatic reaction. The pumping velocity increases with increasing substrate concentration and reaction rate. These rechargeable pumps can be triggered 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 molecules and proteins in response to specific chemical stimuli, including the release of insulin in response to glucose. PMID:24755593

Sengupta, Samudra; Patra, Debabrata; Ortiz-Rivera, Isamar; Agrawal, Arjun; Shklyaev, Sergey; Dey, Krishna K; Córdova-Figueroa, Ubaldo; Mallouk, Thomas E; Sen, Ayusman

2014-05-01

47

Divergence and convergence in enzyme evolution.  

PubMed

Comparative analysis of the sequences of enzymes encoded in a variety of prokaryotic and eukaryotic genomes reveals convergence and divergence at several levels. Functional convergence can be inferred when structurally distinct and hence non-homologous enzymes show the ability to catalyze the same biochemical reaction. In contrast, as a result of functional diversification, many structurally similar enzyme molecules act on substantially distinct substrates and catalyze diverse biochemical reactions. Here, we present updates on the ATP-grasp, alkaline phosphatase, cupin, HD hydrolase, and N-terminal nucleophile (Ntn) hydrolase enzyme superfamilies and discuss the patterns of sequence and structural conservation and diversity within these superfamilies. Typically, enzymes within a superfamily possess common sequence motifs and key active site residues, as well as (predicted) reaction mechanisms. These observations suggest that the strained conformation (the entatic state) of the active site, which is responsible for the substrate binding and formation of the transition complex, tends to be conserved within enzyme superfamilies. The subsequent fate of the transition complex is not necessarily conserved and depends on the details of the structures of the enzyme and the substrate. This variability of reaction outcomes limits the ability of sequence analysis to predict the exact enzymatic activities of newly sequenced gene products. Nevertheless, sequence-based (super)family assignments and generic functional predictions, even if imprecise, provide valuable leads for experimental studies and remain the best approach to the functional annotation of uncharacterized proteins from new genomes. PMID:22069324

Galperin, Michael Y; Koonin, Eugene V

2012-01-01

48

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

49

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 SocietyÃÂs 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

50

[Microbial keratinolytic enzymes].  

PubMed

Microbial keratinolytic enzymes hydrolyze such a hard dissoluble protein substrate as keratin. Data conserning ability to degrade keratin by various groups of microorganisms and their potential biological role are discussed in the paper. The physical and chemical properties of enzyme preparations of keratinases and methods of their separation and purification have been examined. The available and possible ways of these enzymes application in industry and medicine have been discussed. PMID:19140422

Matseliukh, O V; Varbanets, L D

2008-01-01

51

Indirect Speech Acts  

Microsoft Academic Search

In this paper, we address several puzzles concerning speech acts, particularly indirect speech acts. We show how a formal semantic theory of discourse interpretation can be used to define speech acts and to avoid murky issues concerning the metaphysics of action. We provide a formally precise definition of indirect speech acts, including the subclass of so-called conventionalized indirect speech acts.

Nicholas Asher; Alex Lascarides

52

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.

2008-10-22

53

Nanostructures for enzyme stabilization  

SciTech Connect

The last decade has witnessed notable breakthroughs in nanotechnology with development of various nanostructured materials such as mesoporous materials and nanoparticles. These nanostructures have been used as a host for enzyme immobilization via various approaches, such as enzyme adsorption, covalent attachment, enzyme encapsulation, and sophisticated combinations of methods. This review discusses the stabilization mechanisms behind these diverse approaches; such as confinement, pore size and volume, charge interaction, hydrophobic interaction, and multipoint attachment. In addition, we will introduce recent rigorous approaches to improve the enzyme stability in these nanostructures or develop new nanostructures for the enzyme stabilization. Especially, we will introduce our recent invention of a nanostructure, called single enzyme nanoparticles (SENs). In the form of SENs, each enzyme molecule is surrounded with a nanometer scale network, resulting in stabilization of enzyme activity without any serious limitation for the substrate transfer from solution to the active site. SENs can be further immobilized into mesoporous silica with a large surface area, providing a hierarchical approach for stable, immobilized enzyme systems for various applications, such as bioconversion, bioremediation, and biosensors.

Kim, Jungbae; Grate, Jay W.; Wang, Ping

2006-02-02

54

Dissipative dynamics of enzymes.  

PubMed

We explore enzyme conformational dynamics at sub-Å 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. PMID:25415926

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

2014-11-01

55

Dissipative Dynamics of Enzymes  

NASA Astrophysics Data System (ADS)

We explore enzyme conformational dynamics at sub-Å 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

56

Enzyme Immobilization Alternatives For the Enzyme Alarm.  

National Technical Information Service (NTIS)

Samples of glass beads, modified starch urethane pads, nylon and urethane enzyme products which passed wash-out resistance were sent to Edgewood Arsenal. Glass bead products and nylon products do not seem suitable for the alarm. Urethane pads including ch...

H. W. Levin, E. S. Erenrich

1975-01-01

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

Catalyzed enzyme electrodes  

Microsoft Academic Search

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

Thomas A. Zawodzinski; Mahlon S. Wilson; Judith Rishpon; Shimshon Gottesfeld

1993-01-01

59

Catalyzed enzyme electrodes  

Microsoft Academic Search

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

T. A. Zawodzinski; M. S. Wilson; J. Rishpon; S. Gottesfeld

1992-01-01

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

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

62

Oxygen-independent oxidases: A new class of enzymes for application in diagnostics  

Microsoft Academic Search

Some years ago, a new class of enzymes, the quinoproteins, were described. They are oxygen-independent oxidases. Common to this class of enzymes is the content of pyrroloquinoline quinone, which acts as a redox centre. These enzymes can transfer electrons from substrates such as glucose to electron acceptors such as cytochromes. They do not transfer electrons to oxygen. This property is

B. Schmidt

1997-01-01

63

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

64

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

65

Mechanisms, biology and inhibitors of deubiquitinating enzymes  

Microsoft Academic Search

The addition of ubiquitin (Ub) and ubiquitin-like (Ubl) modifiers to proteins serves to modulate function and is a key step in protein degradation, epigenetic modification and intracellular localization. Deubiquitinating enzymes and Ubl-specific proteases, the proteins responsible for the removal of Ub and Ubls, act as an additional level of control over the ubiquitin-proteasome system. Their conservation and widespread occurrence in

Kerry Routenberg Love; André Catic; Christian Schlieker; Hidde L Ploegh

2007-01-01

66

The EBI enzyme portal  

PubMed Central

The availability of comprehensive information about enzymes plays an important role in answering questions relevant to interdisciplinary fields such as biochemistry, enzymology, biofuels, bioengineering and drug discovery. At the EMBL European Bioinformatics Institute, we have developed an enzyme portal (http://www.ebi.ac.uk/enzymeportal) to provide this wealth of information on enzymes from multiple in-house resources addressing particular data classes: protein sequence and structure, reactions, pathways and small molecules. The fact that these data reside in separate databases makes information discovery cumbersome. The main goal of the portal is to simplify this process for end users. PMID:23175605

Alcantara, Rafael; Onwubiko, Joseph; Cao, Hong; de Matos, Paula; Cham, Jennifer A.; Jacobsen, Jules; Fischer, Julia D.; Rahman, Syed Asad; Jassal, Bijay; Goujon, Mikael; Rowland, Francis; Velankar, Sameer; Lopez, Rodrigo; Overington, John P.; Kleywegt, Gerard J.; Hermjakob, Henning; O'Donovan, Claire; Martin, Maria Jesus; Thornton, Janet M.; Steinbeck, Christoph

2013-01-01

67

Enzymes in Analytical Chemistry.  

ERIC Educational Resources Information Center

Presents tabular information concerning recent research in the field of enzymes in analytic chemistry, with methods, substrate or reaction catalyzed, assay, comments and references listed. The table refers to 128 references. Also listed are 13 general citations. (CS)

Fishman, Myer M.

1980-01-01

68

Glucocorticoid metabolism and reproduction: a tale of two enzymes  

Microsoft Academic Search

Within potential target cells, the actions of physiological glucocorticoids (cortisol and corticosterone) are modulated by isoforms of the enzyme 11-hydroxysteroid de- hydrogenase (11HSD). To date, two isoforms of 11HSD have been cloned: 11HSD1 acts predominantly as an NADP(H)-dependent reductase to generate active cortisol or corticosterone, and 11HSD2 is a high affinity NAD+-dependent enzyme that catalyses the enzymatic inactivation of glucocorticoids.

Anthony E. Michael; Lisa M. Thurston; Michael T. Rae

2003-01-01

69

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

70

[Enzymes of snake venoms].  

PubMed

Snakes' venom is a mixture of biologically active substances, containing proteins and peptides. A number of these proteins interact with haemostasis system components. Activators and inhibitors affecting blood coagulation and fibrinolysis systems are of special interest. Venom components can be classified into three main groups, such as procoagulants, anticoagulants and fibrinolytic enzymes according to their action. This review is focused on enzymes from Agkistrodon halys halys venom. They are thrombine-like enzyme, named Ancystron-H, flbrinogenolytic enzyme, protein C activator and platelet aggregation inhibitor. Ancystron-H is used for determination of fibrinogen level in blood plasma of patients undergoing heparin treatment and blood coagulation inhibitors accumulation. The fibrinogenolytic enzyme can be used as the instrument for protein-protein interactions in fibrinogen-fibrin system. The protein C activator is used for protein C level determination in blood plasma with different pathologies. Functions of the platelet aggregation inhibitor, belonging to disintegrins group, can be used for development of antithrombotic preparations. Information about the use of snake venoms in science and medicine is presented. PMID:14577148

Gornitskaia, O V; Platonova, T N; Volkov, G L

2003-01-01

71

ACTS data center  

NASA Technical Reports Server (NTRS)

Viewgraphs on ACTS Data Center status report are included. Topics covered include: ACTS Data Center Functions; data flow overview; PPD flow; RAW data flow; data compression; PPD distribution; RAW Data Archival; PPD Audit; and data analysis.

Syed, Ali; Vogel, Wolfhard J.

1993-01-01

72

ACTS data center  

NASA Astrophysics Data System (ADS)

Viewgraphs on ACTS Data Center status report are included. Topics covered include: ACTS Data Center Functions; data flow overview; PPD flow; RAW data flow; data compression; PPD distribution; RAW Data Archival; PPD Audit; and data analysis.

Syed, Ali; Vogel, Wolfhard J.

1993-08-01

73

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 SocietyÃÂs 2007 Frontiers in Physiology Program. For more information on this program, please visit www.frontiersinphys.org.

Dawn DeMayo (Montclair High School)

2007-08-01

74

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.

2008-08-13

75

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

76

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

77

Oxidizing enzymes as biocatalysts  

Microsoft Academic Search

This article describes oxidising enzymes used for biocatalytic applications. Redox biocatalysts are highly sought after because of the selectivity, controllability and economy of their reactions, in comparison with conventional chemical reactions. Increasing numbers of oxidative biotransformations are being reported, indicating wide variability in the biocatalyst characteristics and a range of potential and established applications. Several limitations apply to oxidative biotransformations,

Stephanie G. Burton

2003-01-01

78

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

79

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; Morl, Mario

2007-01-01

80

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

81

Caught in the act.  

PubMed

The crystal structure of a HECT E3 enzyme has been captured as it transfers ubiquitin to a target protein, revealing the dramatic changes in shape that enable it to modify particular residues in its targets. PMID:23936629

Meyer, Hermann-Josef; Rape, Michael

2013-01-01

82

Deubiquitylating enzymes and disease  

Microsoft Academic Search

: Deubiquitylating enzymes (DUBs) can hydrolyze a peptide, amide, ester or thiolester bond at the C-terminus of UBIQ (ubiquitin), including the post-translationally formed branched peptide bonds in mono- or multi-ubiquitylated conjugates. DUBs thus have the potential to regulate any UBIQ-mediated cellular process, the two best characterized being proteolysis and protein trafficking. Mammals contain some 80–90 DUBs in five different subfamilies,

Shweta Singhal; Matthew C Taylor; Rohan T Baker

2008-01-01

83

RNase P enzymes  

PubMed Central

Ribonuclease P (RNase P) catalyzes the maturation of the 5? end of precursor-tRNAs (pre-tRNA) and is conserved in all domains of life. However, the composition of RNase P varies from bacteria to archaea and eukarya, making RNase P one of the most diverse enzymes characterized. Most known RNase P enzymes contain a large catalytic RNA subunit that associates with one to 10 proteins. Recently, a protein-only form of RNase P was discovered in mitochondria and chloroplasts of many higher eukaryotes. This proteinaceous RNase P (PRORP) represents a new class of metallonucleases. Here we discuss our recent crystal structure of PRORP1 from Arabidopsis thaliana and speculate on the reasons for the replacement of catalytic RNA by a protein catalyst. We conclude, based on an analysis of the catalytic efficiencies of ribonucleoprotein (RNP) and PRORP enzymes, that the need for greater catalytic efficiency is most likely not the driving force behind the replacement of the RNA with a protein catalyst. The emergence of a protein-based RNase P more likely reflects the increasing complexity of the biological system, including difficulties in importation into organelles and vulnerability of organellar RNAs to cleavage. PMID:23595059

Howard, Michael J.; Liu, Xin; Lim, Wan Hsin; Klemm, Bradley P.; Fierke, Carol A.; Koutmos, Markos; Engelke, David R.

2013-01-01

84

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

85

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

86

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

87

On Acting from Duty  

E-print Network

 ON ACTING FROM DUTY An Undergraduate Research Scholars Thesis by JORDAN MICHAEL FOSSEE Submitted to Honors and Undergraduate Research Texas A&M University in partial fulfillment of the requirements for the designation as an UNDERGRADUATE... of Duty .................................................................................3 II. THE ISSUE ....................................................................................................6 Stocker’s Implications for Acting from Duty...

Fossee, Jordan Michael

2013-09-24

88

FAIR LABOR STANDARDS ACT  

E-print Network

FAIR LABOR STANDARDS ACT (FLSA) ADMINISTRATIVE GUIDE FOR MANAGERS AND SUPERVISORS of New Overtime Regulations The Fair Labor Standards Act of 1938 (FLSA) is one of the most important labor regulations affecting compensation in the workplace. These regulations have remained basically

Liu, Alice Y.C.

89

Speech Acts On Trial  

Microsoft Academic Search

In this document we discuss the general applicability of the speech act theory, as a theoretical foundation in the design of information technology (IT). We pay special attention to the acclimatization that speech act theory has undergone when applied in the IT-field. One of the questions we address concerns what happens when we import passive descriptive theories from other disciplines

Jan Ljungberg; Peter Holm

1996-01-01

90

Act 195 (Revised).  

ERIC Educational Resources Information Center

This monograph presents an overview of Pennsylvania's law governing collective bargaining for public employees (Act 195) and reviews Pennsylvania's experience under the law since its enactment in 1970. The passage of Act 195 for the first time made it possible for Pennsylvania public employees to bargain collectively and to legally strike when…

Pennsylvania School Boards Association, Inc., Harrisburg.

91

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

92

Enzyme stabilization for pesticide degradation  

Microsoft Academic Search

Enzymes offer inherent advantages and limitations as active components of formulations used to decontaminate soil and equipment contaminated with toxic materials such as pesticides. Because of the catalytic nature of enzymes, each molecule of enzyme has the potential to destroy countless molecules of a contaminating toxic compound. This degradation takes place under mild environmental conditions of pH, temperature, pressure, and

D. B. Rivers; F FRAZERIII; D. W. Mason; T. R. Tice

1988-01-01

93

Catalase Hybrid Enzymes in Maize  

Microsoft Academic Search

In maize endosperm there are two electrophoretic variants of catalase. The variations are under genetic control, and the heterozygote shows three hybrid enzymes with mobilities intermediate between the parental enzymes. Thus, maize catalase may exist as a tetramer, and the hybrid enzymes may be formed by random association of two different catalase monomers.

Lars Beckman; John G. Scandalios; James L. Brewbaker

1964-01-01

94

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

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 (CysM...

Messer, Kayla J.

2012-07-16

96

Mannan transglycosylase: a novel enzyme activity in cell walls of higher plants  

Microsoft Academic Search

Mannan transglycosylase is a novel cell wall enzyme activity acting on mannan-based plant polysaccharides in primary cell walls of monocotyledons and dicotyledons. The enzyme activity was detected by its ability to transfer galactoglucomannan (GGM) polysaccharides to tritium-labelled GGM-derived oligosaccharides generating tritium-labelled GGM polysaccharides. Mannan transglycosylase was found in a range of plant species and tissues. High levels of the enzyme

Roswitha Schröder; Teresa F. Wegrzyn; Karen M. Bolitho; Robert J. Redgwell

2004-01-01

97

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

98

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

99

The ACTS propagation program  

NASA Technical Reports Server (NTRS)

The purpose of the Advanced Communications Technology Satellite (ACTS) is to demonstrate the feasibility of the Ka-band (20 and 30 GHz) spectrum for satellite communications, as well as to help maintain U.S. leadership in satellite communications. ACTS incorporates such innovative schemes as time division multiple access (TDMA), microwave and baseband switching, onboard regeneration, and adaptive application of coding during rain-fade conditions. The success or failure of the ACTS experiment will depend on how accurately the rain-fade statistics and fade dynamics can be predicted in order to derive an appropriate algorithm that will combat weather vagaries, specifically for links with small terminals, such as very small aperture terminals (VSAT's) where the power margin is a premium. This article describes the planning process and hardware development program that will comply with the recommendations of the ACTS propagation study groups.

Chakraborty, Dayamoy; Davarian, Faramaz

1991-01-01

100

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

101

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

102

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

103

The ACTS propagation program  

NASA Technical Reports Server (NTRS)

The success or failure of the ACTS experiment will depend on how accurately the rain-fade statistics and fade dynamics can be predicted in order to derive an appropriate algorithm that will combat weather vagaries, specifically for links with small terminals, such as very small aperture terminals (VSAT's) where the power margin is a premium. The planning process and hardware development program that will comply with the recommendations of the ACTS propagation study groups are described.

Chakraborty, D.; Davarian, Faramaz

1992-01-01

104

Human Lung Angiotensin Converting Enzyme  

PubMed Central

To enable its immunohistologic localization, angiotensin converting enzyme (EC 3.4.15.1) from human lung was solubilized by trypsinization and purified ?2,660-fold to apparent homogeneity from a washed lung particulate fraction. The specific activity of pure enzyme was estimated to be 117 ?mol/min per mg protein with the substrate hippuryl-l-histidyl-l-leucine. Consistent with previously described lung enzyme studies, catalytic activity was strongly inhibited by EDTA, O-phenanthroline, SQ 20,881, and SQ 14,225 and increased by CoCl2. SQ 20,881 was a somewhat more potent inhibitor than SQ 14,225, unlike rabbit lung enzyme. The Michaelis constant (Km) with hippuryl-l-histidyl-l-leucine was 1.6 mM. The molecular weight was estimated at 150,000 from sucrose density gradient centrifugation. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed a single polypeptide chain estimated at 130,000 daltons. Rabbit antibody to human lung enzyme was prepared by parenteral administration of pure angiotensin-converting enzyme in Freund's adjuvant. Rabbit antibody to human lung angiotensin-converting enzyme appeared to crossreact weakly with the rabbit enzyme and strongly inhibited the catalytic activity of the enzymes from human serum, lung, and lymph node. The specificity of the rabbit antibody and purity of the final human lung enzyme preparation was suggested by the single precipitin lines obtained by radial double immunodiffusion, and by the coincidence of enzyme catalytic activity and immunoreactivity on polyacrylamide gel electrophoresis, with both relatively pure and highly impure enzymes. Generally applicable sensitive analysis of acrylamide gels for immunoreactivity (and subsequently for any other activity) by use of intact gel slices in radial double immunodiffusion was devised. Human lung enzyme was very tightly bound to and catalytically active on anti-human enzyme antibody covalently bound to Sepharose 4B, and could not be readily dissociated without inactivation. Antibody to human lung angiotensin converting enzyme has permitted tissue localization of the enzyme, which appears to be clinically useful in diseases associated with abnormal abundance of angiotensin-converting enzyme in tissues, such as sarcoidosis. Images PMID:6259212

Friedland, Joan; Silverstein, Emanuel; Drooker, Martin; Setton, Charlotte

1981-01-01

105

The CEO's second act.  

PubMed

When a CEO leaves because of performance problems, the company typically recruits someone thought to be better equipped to fix what the departing executive couldn't--or wouldn't. The board places its confidence in the new person because of the present dilemma's similarity to some previous challenge that he or she dealt with successfully. But familiar problems are inevitably succeeded by less familiar ones, for which the specially selected CEO is not quite so qualified. More often than not, the experiences, skills, and temperament that yielded triumph in Act I turn out to be unequal to Act II's difficulties. In fact, the approaches that worked so brilliantly in Act I may be the very opposite of what is needed in Act II. The CEO has four choices: refuse to change, in which case he or she will be replaced; realize that the next act requires new skills and learn them; downsize or circumscribe his or her role to compensate for deficiencies; or line up a successor who is qualified to fill a role to which the incumbent's skills and interests are no longer suited. Hewlett-Packard's Carly Fiorina exemplifies the first alternative; Merrill Lynch's Stanley O'Neal the second; Google's Sergey Brin and Larry Page the third; and Quest Diagnostics' Ken Freeman the fourth. All but the first option are reasonable responses to the challenges presented in the second acts of most CEOs' tenures. And all but the first require a power of observation, a propensity for introspection, and a strain of humility that are rare in the ranks of the very people who need those qualities most. There are four essential steps executives can take to discern that they have entered new territory and to respond accordingly: recognition that their leadership style and approach are no longer working; acceptance of others' advice on why performance is faltering; analysis and understanding of the nature of the Act II shift; and, finally, decision and action. PMID:17286076

Nadler, David A

2007-01-01

106

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

107

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

...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

108

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

109

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

110

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

111

ENZYMES IN CANDIDA ALBICANS II.  

PubMed Central

Rao, G. Ramananda (Indian Institute of Science, Bangalore, India), M. Sirsi, and T. Ramakrishnan. Enzymes in Candida albicans. II. Tricarboxylic acid cycle and related enzymes. J. Bacteriol. 84:778–783. 1962.—Evidence is presented to show the operation of the tricarboxylic acid cycle in Candida albicans, by studies with whole cells, cell-free preparations, and by the demonstration of most of the enzymes involved in the cycle. Cell-free extracts contained the following enzymes: condensing enzyme; aconitase; isocitric, ?-ketoglutaric, succinic, and malic dehydrogenases; malic enzyme; fumarase; reduced diphosphopyridine nucleotide (DPNH) oxidase; DPNH-cytochrome c reductase; reduced triphosphopyridine nucleotide (TPNH) cytochrome c reductase; and diaphorase. Pyruvic dehydrogenase, TPNH oxidase, and transhydrogenase activities could not be detected under the test conditions. PMID:13973046

Rao, G. Ramananda; Sirsi, M.; Ramakrishnan, T.

1962-01-01

112

Enzyme stabilization for pesticide degradation  

SciTech Connect

Enzymes offer inherent advantages and limitations as active components of formulations used to decontaminate soil and equipment contaminated with toxic materials such as pesticides. Because of the catalytic nature of enzymes, each molecule of enzyme has the potential to destroy countless molecules of a contaminating toxic compound. This degradation takes place under mild environmental conditions of pH, temperature, pressure, and solvent. The basic limitation of enzymes is their degree of stability during storage and application conditions. Stabilizing methods such as the use of additives, covalent crosslinking, covalent attachment, gel entrapment, and microencapsulation have been directed developing an enzyme preparation that is stable under extremes of pH, temperature, and exposure to organic solvents. Initial studies were conducted using the model enzymes subtilisin and horseradish peroxidase.

Rivers, D.B.; Frazer, F.R. III; Mason, D.W.; Tice, T.R.

1988-01-01

113

Proteolytic enzymes of Phymatotrichum omnivorum  

E-print Network

at bonds internal to the ends of the protein molecule and the exopeptidases, which cleave amino acids from the terminal ends of the molecule. Proteolytic enzymes may also be distinguished as to whether they exert their activity within the cell... of Molds In a review of the proteolytic enzymes of molds, Hagihara (2) discusses Matsushima's classification of these enzymes into four types, based on pH activity curves obtained with casein as a substrate. Hagihara suggests that casein is not a good...

Burgum, Alexis August

2012-06-07

114

Thermostable enzymes for industrial applications  

Microsoft Academic Search

Summary The variety of thermostable (TS) enzymes has been steadily increasing for use in industrial applications, mainly as replacements for thermolabile (TL) enzymes. For example, TS amylases fromBacillus licheniformis andBacillus stearothermophilus have replaced TL amylases fromBacillus subtilis. TS enzymes also have advantages in new areas such as cyclodextrin production. The TS cyclodextrin glycosyl transferase (CGTase) fromThermoanaerobacter sp. (95°C optimum) gives

Bruce L. Zamost; Henrik K. Nielsen; Robert L. Starnes

1991-01-01

115

ACTS broadband aeronautical terminal  

NASA Technical Reports Server (NTRS)

This paper discusses the design of, and experiments with, the ACTS Broadband Aeronautical Terminal. As part of the ongoing effort to investigate commercial applications of ACTS technologies, NASA's Jet Propulsion Laboratory and various industry/government partners are developing a broadband mobile terminal for aeronautical applications. The ACTS Broadband Aeronautical Terminal is designed to explore the use of K/Ka-band for high data rate aeronautical satellite communications. Currently available commercial aeronautical satellite communications systems are only capable of achieving data rates on the order of tens of kilobits per second. The broadband terminal used in conjunction with the ACTS mechanically steerable antenna, can achieve data rates of 384 kilobits per second, while use of an ACTS spot beam antenna with this terminal will allow up to T1 data rates (1.544 megabits per second). The aeronautical terminal will be utilized to test a variety of applications that require a high data rate communications link. The use of the K/Ka-band for wideband aeronautical communications has the advantages of spectrum availability and smaller antennas, while eliminating the one major drawback of this frequency band, rain attenuation, by flying above the clouds the majority of the time.

Agan, M. J.; Densmore, A. C.

1995-01-01

116

Rapid electrochemical enzyme assay with enzyme-free calibration.  

PubMed

The internally calibrated electrochemical continuous enzyme assay (ICECEA, patent pending) was developed for the fast determination of enzyme activity unit (U). The assay depends on the integration of enzyme-free preassay calibration with the actual enzyme assay in one continuous experiment. Such integration resulted in a uniquely shaped amperometric trace that allowed for the selective picomolar determination of redox enzymes. The ICECEA worked because the preassay calibration did not interfere with the enzyme assay allowing both measurements to be performed in succession in the same solution and at the same electrode. The method displayed a good accuracy (relative error, <3%) and precision (relative standard deviation (RSD), <3%) when tested with different working electrodes (carbon nanotubes/chitosan, glassy carbon, platinum) and enzymes (alcohol dehydrogenase, ADH; lactate dehydrogenase, LDH; xanthine oxidase, XOx; glucose oxidase, GOx). The limit of detection for the ADH, LDH, XOx, and GOx was equal to 0.18, 0.14, 0.0031, and 0.11 U L(-1) (or 4.2, 0.72, 89, and 6.0 pM), respectively. The simplicity, reliability, and short analysis time make the ICECEA competitive with the optical enzyme assays currently in use. PMID:23697336

Zhang, Maogen; Karra, Sushma; Gorski, Waldemar

2013-06-18

117

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

118

Affordable Care Act.  

PubMed

The Patient Protection and Affordable Care Act of 2010 (PPACA), although a subject of much debate in the Unites States, was enacted on March 23, 2010, and upheld by the Supreme Court on June 28, 2012. This act advocates that "healthcare is a right, not a privilege." The main goals of PPACA are to minimize the number of uninsured Americans and make healthcare available to everyone at an affordable price. The Congressional Budget Office has determined that 94% of Americans will have healthcare coverage while staying under the $900 billion limit that President Barack Obama established by bending the healthcare cost curve and reducing the deficit over the next 10 years. PMID:23767130

Rak, Sofija; Coffin, Janis

2013-01-01

119

Action of degradative enzymes on the light fraction of bovine septa protein polysaccharide  

PubMed Central

1. Fragments from enzymic degradation of protein–polysaccharide light fraction (PPL) have been analysed. 2. The time-course of action of some proteolytic enzymes and of hyaluronidase on PPL has been followed by viscometric techniques. 3. It is suggested that papain acts to produce single polysaccharide chains, whereas other proteolytic enzymes tried give evidence of twin-chain residues. 4. The molecular weight of the fragments derived from complete enzyme action on PPL supports this postulate. 5. A structure of the PPL complex is suggested. PMID:6033751

Luscombe, Mollie; Phelps, C. F.

1967-01-01

120

ACTS OF VIOLENCE ANNEX V ACTS OF VIOLENCE  

E-print Network

ANNEX V ACTS OF VIOLENCE #12;ANNEX V ­ ACTS OF VIOLENCE 07/25/2012 v.1.0 Page V-1 PROMULGATION STATEMENT Annex V: Acts of Violence, and contents within, is a guide to how the University conducts an emergency response specific to an act of violence. The Annex is written in support of the TAMU Emergency

121

The Kentucky Civil Rights Act: Explanation, the Act, Regulations.  

ERIC Educational Resources Information Center

The Kentucky Civil Rights Act, introduced on January 4, 1966, enacted January 27, 1966 and effective July 1, 1966 is said to meet the requirements of the Federal Civil Rights Act of 1964. In 1968, the Act was amended to prohibit housing discrimination. In 1972, the coverage of the Act was extended to prohibit employment discrimination because of…

Kentucky State Commission on Human Rights, Frankfort.

122

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,

123

Enzyme catalysis: Evolution made easy  

NASA Astrophysics Data System (ADS)

Directed evolution is a powerful tool for the development of improved enzyme catalysts. Now, a method that enables an enzyme, its encoding DNA and a fluorescent reaction product to be encapsulated in a gel bead enables the application of directed evolution in an ultra-high-throughput format.

Wee, Eugene J. H.; Trau, Matt

2014-09-01

124

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

125

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

126

Spore lytic enzyme released from Clostridium perfringens spores during germination.  

PubMed Central

The exudate of fully germinated spores of Clostridium perfringens was found to contain a large amount of a spore lytic enzyme which acted directly on alkali-treated spores of the organism to cause germination. Although no detectable amount of the enzyme was found in dormant spores during germination in a KCl medium, the enzyme was produced rapidly and released into the medium. The optimal conditions for enzyme activity were pH 6.0 and 45 degrees C. Maximum activity occurred in the presence of various univalent cations at a concentration of 50 mM. The enzyme was readily inactivated by several sulfhydryl reagents. A strong reducing condition was generated in the ionic germination of the spores, a minimum Eh level of -350 mV being reached 30 min after initiation of germination. Furthermore, adenosine triphosphate-dependent pyruvate:ferredoxin oxidoreductase (EC 1.2.7.1) was identified in both dorman and germinated spores. The relationship between the release of active enzyme and the generation of reducing conditions during germination is discussed. PMID:227836

Ando, Y

1979-01-01

127

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

128

OSTP gets acting director  

Microsoft Academic Search

Amid rumors that the Office of Science and Technology Policy (OSTP) will be abolished, President Reagan appointed Benjamin Huberman as acting director, effective March 5.Although the size and shape of the science policy office and the influence it will have under the Reagan administration are undetermined, rumors that the office will be abolished should be discounted, an OSTP official said.

Barbara T. Richman

1981-01-01

129

ACTS Mobile Terminals  

NASA Technical Reports Server (NTRS)

The development of the Advanced Communications Technology Satellite (ACTS) Mobile Terminal (AMT) and its follow-on, the Broadband Aeronautical Terminal (BAT), have provided an excellent testbed for the evaluation of K- and Ka-band mobile satellite communications systems. An overview of both of these terminals is presented in this paper.

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

1997-01-01

130

Let's Act Like Professionals  

ERIC Educational Resources Information Center

In this article, the author discusses some of the most serious challenges--intellectual, institutional, and political--that he sees for the future of professional learning in education. He states that one common solution to these challenges would be for educators to begin to act more like professionals. One thing is clear about the early stages of…

Elmore, Richard F.

2007-01-01

131

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

132

Derwent's Doors: Creative Acts  

Microsoft Academic Search

Children's early word learning is not usually considered creative in the same sense as artistic productions of later life. Yet early word learning is a creative response to the intrinsic instability of word meaning. As the child acts to participate in her community, she strives for intersubjectivity, manifest in neologisms and under- and overextensions, commonly characterized as errors. Young children's

Julia Gillen

2007-01-01

133

Enzyme-carrying electrospun nanofibers.  

PubMed

Compared to other nanomaterials as supports for enzyme immobilization, nanofibers provide a promising configuration in balancing the key factors governing the catalytic performance of the immobilized enzymes including surface area-to-volume ratio, mass transfer resistance, effective loading, and the easiness to recycle. Synthetic and natural polymers can be fabricated into nanofibers via a physical process called electrospinning. The process requires only simple apparatus to operate, yet has proved to be very flexible in the selection of feedstock materials and also effective to control and manipulate the properties of the resulting nanofibers such as size and surface morphology, which are typically important parameters for enzyme immobilization supports. This chapter describes a protocol for the preparation of nanofibrous enzyme, involving the synthesis and end-group functionalization of polystyrene, production of electrospun nanofibers, and surface immobilization of enzyme via covalent attachment. PMID:21553193

Jia, Hongfei

2011-01-01

134

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

135

Activated clotting time (ACT).  

PubMed

The standard assay for monitoring anticoagulation during extracorporeal life support (ECLS) is the activated clotting time (ACT) test, with celite, kaolin, and glass beads being the most commonly used activators to initiate contact activation. The point-of-care ACT test has been the preferred test in catheterization labs and cardiac theatres because it has a number of advantages over laboratory tests (Spinler et al., Ann Pharmacother 39(7-8):1275-1285, 2005): Shorter time between sampling and results. Smaller blood sample size. Availability to have test performed by non-lab personnel. Reduced errors associated with sample mislabeling/mishandling. Decreased risk of sample degradation with time. There are other coagulation monitoring tests available; however these are usually specific and do not take into account the global picture of the entire clotting system. The standard coagulation tests (prothrombin time (PT), activated partial thromboplastin time, thrombin time (TT), and fibrinogen level) are plasma tests measuring plasma haemostasis and not patient haemostasis. The ACT measurement uses whole blood, thereby incorporating the importance of platelets and phospholipids in the role of coagulation. Many of the problems with the haemostatic system during ECLS are caused by the activation of platelets, which are not detected by standard tests. Because an ACT test is nonspecific there are many variables such as hypothermia, platelets, aprotinin, GP IIb/IIIa antagonists, haemodilution, etc. that can alter its results. For this reason it is important to gain an understanding as to how these variables interact for meaningful interpretation of the ACT test result. PMID:23546712

Horton, Stephen; Augustin, Simon

2013-01-01

136

Kinetic analysis of enzyme systems with suicide substrate in the presence of a reversible competitive inhibitor, tested by simulated progress curves  

Microsoft Academic Search

The use of suicide substrates remains a very important and useful method in enzymology for studying enzyme mechanisms and designing potential drugs. Suicide substrates act as modified substrates for the target enzymes and bind to the active site. Therefore the presence of a competitive reversible inhibitor decreases the rate of substrate-induced inactivation and protects the enzyme from this inactivation. This

M. A. Moruno-Dávila; C. Garrido-del Solo; M. Garc??a-Moreno; B. H. Havsteen; F. Garcia-Sevilla; F. Garcia-Cánovas; R. Varón

2001-01-01

137

Magnetosensitive enzyme electrode for hydrogen peroxide sensing  

NASA Astrophysics Data System (ADS)

Peroxidase is one of the magnetosensitive enzymes, and has an important role in scavenging reactive oxygen species. In the present study, a surface of platinum black electrode was laminated by peroxidase molecules, and H2O2 decomposing processes by peroxidase and platinum black were monitored with and without magnetic fields of up to 14 T. An increase in the current reflected a decrease in the activity of peroxidase molecules. The current in the electrode with peroxidase increased significantly depending on the applied magnetic flux intensity. The increases of current during the magnetic field exposures were observed consistently both when the currents were transiently decreasing and at a constant level. It is suggested that the layers of peroxidase molecules on the platinum black cause a distortion by diamagnetic forces acting on the layers, and the distortion is concentrated on a catalytic part in the peroxidase resulting in the observed activity decreases.

Yaoita, M.; Iwasaka, M.; Ueno, S.

2003-05-01

138

Enzyme evolution beyond gene duplication  

PubMed Central

Understanding the evolution of enzyme function after gene duplication has been a major goal of molecular biologists, biochemists and evolutionary biologists alike, for almost half a century. In contrast, the impact that horizontal gene transfer (HGT) has had on the evolution of enzyme specialization and the assembly of metabolic networks has just started to being investigated. Traditionally, evolutionary studies of enzymes have been limited to either the function of enzymes in vitro, or to sequence variability at the population level, where in almost all cases the starting conceptual framework embraces gene duplication as the mechanism responsible for the appearance of genetic redundancy. Very recently, we merged comparative phylogenomics, detection of selection signals, enzyme kinetics, X-ray crystallography and computational molecular dynamics, to characterize the sub-functionalization process of an amino acid biosynthetic enzyme prompted by an episode of HGT in bacteria. Some of the evolutionary implications of these functional studies, including a proposed model of enzyme specialization independent of gene duplication, are developed in this commentary. PMID:24251070

Noda-Garcia, Lianet; Barona-Gomez, Francisco

2013-01-01

139

Glycogenolytic enzymes in sporulating yeast.  

PubMed Central

During meiosis in Saccharomyces cerevisiae, the polysaccharide glycogen is first synthesized and then degraded during the period of spore maturation. We have detected, in sporulating yeast strains, an enzyme activity which is responsible for the glycogen catabolism. The activity was absent in vegetative cells, appeared coincidently with the beginning of glycogenolysis and the appearance of mature ascospores, and increased progressively until spourlation was complete. The specific activity of glycogenolytic enzymes in the intact ascus was about threefold higher than in isolated spores. The glycogenolysis was not due to combinations of phosphorylase plus phosphatase or amylase plus maltase. Nonsporulating cells exhibited litle or no glycogen catabolism and contained only traces of glycogenolytic enzyme, suggesting that the activity is sporulation specific. The partially purified enzyme preparation degraded amylose and glycogen, releasing glucose as the only low-molecular-weight product. Maltotriose was rapidly hydrolyzed; maltose was less susceptible. Alpha-methyl-D-glucoside, isomaltose, and linear alpha-1,6-linked dextran were not attacked. However, the enzyme hydrolyzed alpha-1,6-glucosyl-Schardinger dextrin and increased the beta-amylolysis of beta-amylase-limit dextrin. Thus, the preparation contains alpha-1,4- and alpha-1,6-glucosidase activities. Sephadex G-150 chromatography partially resolved the enzyme into two activities, one of which may be a glucamylase and the other a debranching enzyme. Images PMID:350852

Colonna, W J; Magee, P T

1978-01-01

140

Georgia Shore Assistance Act  

SciTech Connect

The Georgia General Assembly passed the Shore Assistance Act in 1979 in order to fill a regulatory gap in the state's management of its coastal resources. A review of its legislative history, purposes, applications, and effects in terms of the sand sharing system of sand dunes, beaches, sandbars, and shoals concludes that the Act is poorly drafted. In its application on the oceanfront, it betrays its intent and protects the oceanfront owner. It has failed to satisfy the requirements of the public trust in the tidal foreshore. Amendments to clarify its understanding of the functions and values of the sand-sharing system should also conform with the state's duties under the public trust. 139 references.

Pendergrast, C.

1984-01-01

141

Dreams and acting out.  

PubMed

Dreams can be used as containers that free patients from increased tension. This may be the principal function of certain types of dreams, called "evacuative dreams." They are dreams used for getting rid of unbearable affects and unconscious fantasies, or as a safety valve for partial discharge of instinctual drives. These dreams are observed primarily in borderline and psychotic patients, but can also be seen in the regressive states of neurotic patients during weekends and other periods of separation. Such dreams have to be differentiated from "elaborative dreams," which have a working-through function and stand in an inverse relationship to acting out: the greater the production of elaborative dreams, the less the tendency to act out, and vice versa. PMID:3562698

Grinberg, L

1987-01-01

142

Understanding Evil Acts  

Microsoft Academic Search

Evil acts strike us, by their very nature, as not only horrifying and reprehensible, but also as deeply puzzling. No doubt\\u000a for reasons like this, evil has often been seen as mysterious, demonic and beyond our human powers of understanding. The question\\u000a I examine in this paper is whether or not we can (or would want to) overcome this puzzlement

Paul Formosa

2007-01-01

143

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

144

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

145

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...

146

The origins of enzyme kinetics.  

PubMed

The equation commonly called the Michaelis-Menten equation is sometimes attributed to other authors. However, although Victor Henri had derived the equation from the correct mechanism, and Adrian Brown before him had proposed the idea of enzyme saturation, it was Leonor Michaelis and Maud Menten who showed that this mechanism could also be deduced on the basis of an experimental approach that paid proper attention to pH and spontaneous changes in the product after formation in the enzyme-catalysed reaction. By using initial rates of reaction they avoided the complications due to substrate depletion, product accumulation and progressive inactivation of the enzyme that had made attempts to analyse complete time courses very difficult. Their methodology has remained the standard approach to steady-state enzyme kinetics ever since. PMID:23791665

Cornish-Bowden, Athel

2013-09-01

147

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

148

Immobilized enzymes affect biofilm formation  

Microsoft Academic Search

The effect of the activity of immobilized enzymes on the initial attachment of pathogenic bacteria commonly associated with\\u000a nosocomial infections (Pseudomonas aeruginosa and Staphylococcus epidermidis) was investigated. The proteolytic enzymes, subtilisin A and the glycoside hydrolase cellulose, were covalently attached\\u000a onto poly(ethylene-alt-maleic) anhydride copolymer films. A comparison between active and heat-inactivated surfaces showed that while the activity\\u000a of immobilized cellulase

Ana L. Cordeiro; Catharina Hippius; Carsten Werner

2011-01-01

149

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

150

21 CFR 864.4400 - Enzyme preparations.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 2013-04-01 false Enzyme preparations. 864.4400 Section 864...Specimen Preparation Reagents § 864.4400 Enzyme preparations. (a) Identification. Enzyme preparations are products that are...

2013-04-01

151

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;

152

21 CFR 864.4400 - Enzyme preparations.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 2010-04-01 false Enzyme preparations. 864.4400 Section 864...Specimen Preparation Reagents § 864.4400 Enzyme preparations. (a) Identification. Enzyme preparations are products that are...

2010-04-01

153

OSTP gets acting director  

NASA Astrophysics Data System (ADS)

Amid rumors that the Office of Science and Technology Policy (OSTP) will be abolished, President Reagan appointed Benjamin Huberman as acting director, effective March 5.Although the size and shape of the science policy office and the influence it will have under the Reagan administration are undetermined, rumors that the office will be abolished should be discounted, an OSTP official said. The search for a full-time, permanent director is underway, according to a White House official. He added that the new administration seems to be looking for someone from industry.

Richman, Barbara T.

154

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.

King, Donna

2012-08-01

155

SOME ENZYMES OF ISOLATED NUCLEI  

PubMed Central

The composition of isolated nuclei and cell preparations from tissues of calf, beef, horse, and fowl was studied with respect to the following components: 1. Liver and kidney arginase, catalase, and uricase; pancreatic lipase and amylase; cardiac muscle myoglobin; erythrocyte hemoglobin; intestinal alkaline phospharase. These are referred to as "special" components in view of their characteristically restricted distribution reflecting the differentiated nature of the tissues in question. 2. Esterase, ?-glucuronidase, alkaline and nucleotide phosphatases, adenosine deaminase, guanase, and nucleoside phosphorylase. These are enzymes of general distribution. The differences in nuclear composition noted with respect to the "special" components, together with the broad variability in nuclear activity found for enzymes of general distribution, led to the conclusion that nuclei are differentiated structures. The following distribution was observed: 1. "Special" components: Hemoglobin was found to be present in fowl and goose erythrocyte nuclei, but myoglobin was entirely absent from heart muscle nuclei; of the special enzymes listed, only catalase and arginase appeared to be concentrated in some of the nuclei. There was no significant nuclear concentration of lipase, amylase, uricase, or alkaline phosphatase. No simple relationship was found between the concentration of a special enzyme in a tissue and its activity in the corresponding nuclei. For example, arginase activity, which is high in mammalian liver and in fowl kidney, was found in liver, not kidney, nuclei. Similarly, catalase activity was demonstrated only in mammalian liver nuclei, although, in mammals, both liver and kidney are rich sources of this enzyme. 2. Enzymes of general distribution fell into three classes: (a) Those present in low concentrations, if at all, in the nuclei—alkaline phosphatase, the nucleotide phosphatases) and ?-glucuronidase. (b) Those present in nuclei in varying concentrations—esterase. (c) Those present in high proportions in most nuclei—adenosine deaminase, nucleoside phosphorylase, and guanase. The exceptionally low nuclear activity of intestinal mucosa with respect to these enzymes was discussed in relation to physiological considerations. The response of nuclei to changes in physiological state was demonstrated by experiments on starvation. The outstanding aspect of this response was a change in nuclear enzymatic activity opposing that observed in the cytoplasm. A comparison of fetal and adult mucosa cells led to the following tentative interpretation of the observed intracellular enzyme distribution: In cells tending to moribundity, as in those subjected to starvation, relative nuclear enzymatic activity falls. The occurrence of special enzymes in nuclei was considered in terms of differentiation, and the high nuclear concentration of the nucleoside-specific enzymes was interpreted in terms of general nuclear metabolic activity. PMID:14898035

Stern, H.; Allfrey, V.; Mirsky, A. E.; Saetren, H.

1952-01-01

156

21 CFR 864.4400 - Enzyme preparations.  

Code of Federal Regulations, 2012 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4400 Enzyme preparations. (a) Identification. Enzyme...

2012-04-01

157

21 CFR 864.4400 - Enzyme preparations.  

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4400 Enzyme preparations. (a) Identification. Enzyme...

2014-04-01

158

21 CFR 864.4400 - Enzyme preparations.  

Code of Federal Regulations, 2011 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4400 Enzyme preparations. (a) Identification. Enzyme...

2011-04-01

159

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

160

Rights, Protections (Affordable Care Act)  

MedlinePLUS

... Act Regulatory and Policy Information For Partners For the Media For Researchers For States Information in other languages ... Act Regulatory and Policy Information For Partners For the Media For Researchers For States Information in other languages ...

161

Enzyme immunoassay (EIA)/enzyme-linked immunosorbent assay (ELISA).  

PubMed

This brief note addresses the historical background of the invention of the enzyme immunoassay (EIA) and enzyme-linked immunosorbent assay (ELISA). These assays were developed independently and simultaneously by the research group of Peter Perlmann and Eva Engvall at Stockholm University in Sweden and by the research group of Anton Schuurs and Bauke van Weemen in The Netherlands. Today, fully automated instruments in medical laboratories around the world use the immunoassay principle with an enzyme as the reporter label for routine measurements of innumerable analytes in patient samples. The impact of EIA/ELISA is reflected in the overwhelmingly large number of times it has appeared as a keyword in the literature since the 1970s. Clinicians and their patients, medical laboratories, in vitro diagnostics manufacturers, and worldwide healthcare systems owe much to these four inventors. PMID:16179424

Lequin, Rudolf M

2005-12-01

162

Enzyme exposure and enzyme sensitisation in the baking industry.  

PubMed Central

OBJECTIVES: To assess the exposure to enzymes and prevalence of enzyme sensitisation in the baking industry. METHODS: A cross sectional study was conducted in four bakeries, one flour mill, and one crispbread factory. Sensitisation to enzymes, flours, and storage mites was examined by skin prick and radioallergosorbent (RAST) tests. 365 workers were tested. The workers were interviewed for work related respiratory and skin symptoms. Total dust concentrations were measured by a gravimetric method, and the concentration of alpha-amylase in air was measured by a catalytic method. An immunochemical method was used for measuring cellulase and xylanase in air. RESULTS: Total measured dust concentrations were from 0.1 to 18 mg/m3, with highest values in dough making areas of bakeries. The alpha-amylase concentrations generally followed the total dust concentrations and reached the highest values < 6.6 micrograms/m3 in the same areas. Cellulase and xylanase varied with concentrations < 180 ng/m3 and < 40 ng/m3, respectively, in the flour mill and the crispbread factory. No cellulase, but concentrations of 1-200 ng/m3 xylanase, were found in the bakeries, probably indicating the natural xylanase activity of wheat. 12 workers (8%) in the bakeries, three (5%) in the flour mill, and four (3%) in the crispbread factory were skin prick positive to enzymes. The corresponding percentages of positive reactions to flours were 12%, 5%, and 8%. CONCLUSIONS: The study confirmed that industrial enzymes in baking used as additives in a powdered form pose a risk of sensitisation. The no effect air concentrations for industrial enzymes are not known. Based on present knowledge, however, lowering exposures and eliminating short and high peaks by technical measures would lower the risk of sensitisation. This would be most effectively accomplished by shifting to non-dusty products. PMID:8943831

Vanhanen, M; Tuomi, T; Hokkanen, H; Tupasela, O; Tuomainen, A; Holmberg, P C; Leisola, M; Nordman, H

1996-01-01

163

A novel 3-sulfinopropionyl coenzyme A (3SP-CoA) desulfinase from Advenella mimigardefordensis strain DPN7T acting as a key enzyme during catabolism of 3,3'-dithiodipropionic acid is a member of the acyl-CoA dehydrogenase superfamily.  

PubMed

3-Sulfinopropionyl coenzyme A (3SP-CoA) desulfinase (AcdDPN7) is a new desulfinase that catalyzes the sulfur abstraction from 3SP-CoA in the betaproteobacterium Advenella mimigardefordensis strain DPN7(T). During investigation of a Tn5::mob-induced mutant defective in growth on 3,3'-dithiodipropionate (DTDP) and also 3-sulfinopropionate (3SP), the transposon insertion was mapped to an open reading frame with the highest homology to an acyl-CoA dehydrogenase (Acd) from Burkholderia phenoliruptrix strain BR3459a (83% identical and 91% similar amino acids). An A. mimigardefordensis ?acd mutant was generated and verified the observed phenotype of the Tn5::mob-induced mutant. For enzymatic studies, AcdDPN7 was heterologously expressed in Escherichia coli BL21(DE3)/pLysS by using pET23a::acdDPN7. The purified protein is yellow and contains a noncovalently bound flavin adenine dinucleotide (FAD) cofactor, as verified by high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS) analyses. Size-exclusion chromatography revealed a native molecular mass of about 173 kDa, indicating a homotetrameric structure (theoretically 179 kDa), which is in accordance with other members of the acyl-CoA dehydrogenase superfamily. In vitro assays unequivocally demonstrated that the purified enzyme converted 3SP-CoA into propionyl-CoA and sulfite (SO3(2-)). Kinetic studies of AcdDPN7 revealed a Vmax of 4.19 ?mol min(-1) mg(-1), an apparent Km of 0.013 mM, and a kcat/Km of 240.8 s(-1) mM(-1) for 3SP-CoA. However, AcdDPN7 is unable to perform a dehydrogenation, which is the usual reaction catalyzed by members of the acyl-CoA dehydrogenase superfamily. Comparison to other known desulfinases showed a comparably high catalytic efficiency of AcdDPN7 and indicated a novel reaction mechanism. Hence, AcdDPN7 encodes a new desulfinase based on an acyl-CoA dehydrogenase (EC 1.3.8.x) scaffold. Concomitantly, we identified the gene product that is responsible for the final desulfination step during catabolism of 3,3'-dithiodipropionate (DTDP), a sulfur-containing precursor substrate for biosynthesis of polythioesters. PMID:23354747

Schürmann, Marc; Deters, Anika; Wübbeler, Jan Hendrik; Steinbüchel, Alexander

2013-04-01

164

A Novel 3-Sulfinopropionyl Coenzyme A (3SP-CoA) Desulfinase from Advenella mimigardefordensis Strain DPN7T Acting as a Key Enzyme during Catabolism of 3,3?-Dithiodipropionic Acid Is a Member of the Acyl-CoA Dehydrogenase Superfamily  

PubMed Central

3-Sulfinopropionyl coenzyme A (3SP-CoA) desulfinase (AcdDPN7) is a new desulfinase that catalyzes the sulfur abstraction from 3SP-CoA in the betaproteobacterium Advenella mimigardefordensis strain DPN7T. During investigation of a Tn5::mob-induced mutant defective in growth on 3,3?-dithiodipropionate (DTDP) and also 3-sulfinopropionate (3SP), the transposon insertion was mapped to an open reading frame with the highest homology to an acyl-CoA dehydrogenase (Acd) from Burkholderia phenoliruptrix strain BR3459a (83% identical and 91% similar amino acids). An A. mimigardefordensis ?acd mutant was generated and verified the observed phenotype of the Tn5::mob-induced mutant. For enzymatic studies, AcdDPN7 was heterologously expressed in Escherichia coli BL21(DE3)/pLysS by using pET23a::acdDPN7. The purified protein is yellow and contains a noncovalently bound flavin adenine dinucleotide (FAD) cofactor, as verified by high-performance liquid chromatography–electrospray ionization mass spectrometry (HPLC-ESI-MS) analyses. Size-exclusion chromatography revealed a native molecular mass of about 173 kDa, indicating a homotetrameric structure (theoretically 179 kDa), which is in accordance with other members of the acyl-CoA dehydrogenase superfamily. In vitro assays unequivocally demonstrated that the purified enzyme converted 3SP-CoA into propionyl-CoA and sulfite (SO32?). Kinetic studies of AcdDPN7 revealed a Vmax of 4.19 ?mol min?1 mg?1, an apparent Km of 0.013 mM, and a kcat/Km of 240.8 s?1 mM?1 for 3SP-CoA. However, AcdDPN7 is unable to perform a dehydrogenation, which is the usual reaction catalyzed by members of the acyl-CoA dehydrogenase superfamily. Comparison to other known desulfinases showed a comparably high catalytic efficiency of AcdDPN7 and indicated a novel reaction mechanism. Hence, AcdDPN7 encodes a new desulfinase based on an acyl-CoA dehydrogenase (EC 1.3.8.x) scaffold. Concomitantly, we identified the gene product that is responsible for the final desulfination step during catabolism of 3,3?-dithiodipropionate (DTDP), a sulfur-containing precursor substrate for biosynthesis of polythioesters. PMID:23354747

Schürmann, Marc; Deters, Anika; Wübbeler, Jan Hendrik

2013-01-01

165

Enzyme kinetics problems 1 Intro Biology Enzyme Kinetics Problems  

E-print Network

.475 9 0.4875 10 0.4975 15 0.5 20 0.5 Enzyme #3 (e3) Initial [A] (mM) V (umols B produced /min) 0 0 1 0 reaction for the initial concentrations listed: Enzyme #1 (e1) Initial [A] (mM) V (umols B produced /min) 0 [A] (mM) V (umols B produced /min) 0 0 1 0.05 2 0.125 3 0.1875 4 0.25 5 0.3125 6 0.375 7 0.4325 8 0

Prestwich, Ken

166

Gender Fairness Using the ACT  

ERIC Educational Resources Information Center

A criticism made against standardized tests is that they may be biased against females because males typically outscore females. On the ACT, males perform only slightly better than females. The population of students who take the ACT is self-selected--that is, the ACT has traditionally been taken primarily by those planning to attend college. For…

ACT, Inc., 2005

2005-01-01

167

Effects of naturally occurring coumarins on hepatic drug-metabolizing enzymes inmice  

Microsoft Academic Search

Cytochromes P450 (P450s) and glutathione S-transferases (GSTs) constitute two important enzyme families involved in carcinogen metabolism. Generally, P450s play activation or detoxifying roles while GSTs act primarily as detoxifying enzymes. We previously demonstrated that oral administration of the linear furanocoumarins, isopimpinellin and imperatorin, modulated P450 and GST activities in various tissues of mice. The purpose of the present study was

Heather E. Kleiner; Xiaojun Xia; Junichiro Sonoda; Jun Zhang; Elizabeth Pontius; Jane Abey; Ronald M. Evans; David D. Moore; John DiGiovanni

2008-01-01

168

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

169

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

170

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

171

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

172

Enzyme-based listericidal nanocomposites.  

PubMed

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 10(5)?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

173

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

174

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

175

Lithuanian biochemist builds enzyme empire  

SciTech Connect

Vidas Janulaitis is professor of biochemistry at the University of Vilnius, head of the Institute of Applied Enzymology - and creator of one of the world's largest collections of restriction enzymes, with more than 100 on offer. He also appears to be the first successful biotechnology entrepreneur to emerge from the former Soviet Union. This paper shows how Janulaitis managed to rise above the chaos that has accompanied the dismantlement of the Soviet Union to become one of the world's top suppliers of new restriction enzymes - especially given that the venture capitalists who rushed off to make deals with Moscow labs in the early days of perestroika mostly came back disappointed.

Dickman, S.

1992-09-11

176

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

177

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

178

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.

179

Taking the Mystery Out of Enzymes.  

ERIC Educational Resources Information Center

Discusses structure and function of enzymes, design of new enzymes and enzyme substitutes, and enzyme uses in industry, medicine, and wastewater treatment. The latter is a low-cost method which can remove as much as 99 percent of toxic substances found in many industrial wastewater streams. (JN)

DeYoung, H. Garrett

1984-01-01

180

Enzyme-based biosilica and biocalcite: biomaterials for the future in regenerative medicine.  

PubMed

The oldest animals on Earth, sponges, form both the calcareous and the siliceous matrices of their spicules enzymatically. Until recently, it has been neglected that enzymes play crucial roles during formation of these biominerals. This paradigm shift occurred after the discovery that the enzyme silicatein, which catalyzes the polycondensation of silica, and the enzyme carbonic anhydrase (CA), which catalyzes the formation of bicarbonate (HCO3(-)/CaCO3), produce solid amorphous bioglass or biocalcite. This suggests that in mammals, biosilica and biocalcite can act anabolically during hydroxyapatite (HA) synthesis and bone formation. Biosilica and biocalcite are thus promising candidates for the fabrication of biomaterials for regenerative medicine. PMID:24908383

Wang, Xiaohong; Schröder, Heinz C; Müller, Werner E G

2014-09-01

181

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

182

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

183

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

184

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

185

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

186

Enzyme encapsulation on chitosan microbeads  

Microsoft Academic Search

The influence of two variables (cross-linking and protein concentration) on the activity shown by ?-amylase and invertase immobilized on chitosan microbeads was studied by means of full factorial experimental designs. Microencapsulation on chitosan beads has shown to be an effective immobilization method for both enzymes and observed differences in their behaviour are explained mainly by the molecular weight of their

M. I. González Siso; E. Lang; B. Carrenõ-Gómez; M. Becerra; F. Otero Espinar; J. Blanco Méndez

1997-01-01

187

Chemical Oscillations in Enzyme Kinetics  

Microsoft Academic Search

The Higgins model is a two variable model in enzyme kinetics. In contrast with other popular simple dynamical models like the Lotka-Volterra model, the Higgins model shows steady states, damped oscillations and stable limit cycles. For these three dynamical behaviors, stability analysis yields expressions of the eigenvalues, which are easy to obtain either analytically or with the use of Mathematica.

Katherine L. Queeney; Ethan P. Marin; Cory M. Campbell; Enrique Peacock-Lopez

1996-01-01

188

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

189

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

190

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

191

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.

192

Trypanosoma cruzi Antioxidant Enzymes As Virulence Factors in Chagas Disease  

PubMed Central

Abstract Significance: Chagas disease (CD) affects several million people in Latin America and is spreading beyond its classical boundaries due to the migration of infected host and insect vectors, HIV co-infection, and blood transfusion. The current therapy is not adequate for treatment of the chronic phase of CD, and new drugs are warranted. Recent Advances: Trypanosoma cruzi is equipped with a specialized and complex network of antioxidant enzymes that are located at different subcellular compartments which defend the parasite against host oxidative assaults. Recently, strong evidence has emerged which indicates that enzyme components of the T. cruzi antioxidant network (cytosolic and mitochondrial peroxiredoxins and trypanothione synthetase) in naturally occurring strains act as a virulence factor for CD. This precept is recapitulated with the observed increased resistance of T. cruzi peroxirredoxins overexpressers to in vivo or in vitro nitroxidative stress conditions. In addition, the modulation of mitochondrial superoxide radical levels by iron superoxide dismutase (FeSODA) influences parasite programmed cell death, underscoring the role of this enzyme in parasite survival. Critical Issues: The unraveling of the biological significance of FeSODs in T. cruzi programmed cell death in the context of chronic infection in CD is still under examination. Future Directions: The role of the antioxidant enzymes in the pathogenesis of CD, including parasite virulence and persistence, and their feasibility as pharmacological targets justifies further investigation. Antioxid. Redox Signal. 19, 723–734. PMID:22458250

Piacenza, Lucia; Peluffo, Gonzalo; Alvarez, Maria Noel; Martinez, Alejandra

2013-01-01

193

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

194

Quantitative comparison of catalytic mechanisms and overall reactions in convergently evolved enzymes: implications for classification of enzyme function.  

PubMed

Functionally analogous enzymes are those that catalyze similar reactions on similar substrates but do not share common ancestry, providing a window on the different structural strategies nature has used to evolve required catalysts. Identification and use of this information to improve reaction classification and computational annotation of enzymes newly discovered in the genome projects would benefit from systematic determination of reaction similarities. Here, we quantified similarity in bond changes for overall reactions and catalytic mechanisms for 95 pairs of functionally analogous enzymes (non-homologous enzymes with identical first three numbers of their EC codes) from the MACiE database. Similarity of overall reactions was computed by comparing the sets of bond changes in the transformations from substrates to products. For similarity of mechanisms, sets of bond changes occurring in each mechanistic step were compared; these similarities were then used to guide global and local alignments of mechanistic steps. Using this metric, only 44% of pairs of functionally analogous enzymes in the dataset had significantly similar overall reactions. For these enzymes, convergence to the same mechanism occurred in 33% of cases, with most pairs having at least one identical mechanistic step. Using our metric, overall reaction similarity serves as an upper bound for mechanistic similarity in functional analogs. For example, the four carbon-oxygen lyases acting on phosphates (EC 4.2.3) show neither significant overall reaction similarity nor significant mechanistic similarity. By contrast, the three carboxylic-ester hydrolases (EC 3.1.1) catalyze overall reactions with identical bond changes and have converged to almost identical mechanisms. The large proportion of enzyme pairs that do not show significant overall reaction similarity (56%) suggests that at least for the functionally analogous enzymes studied here, more stringent criteria could be used to refine definitions of EC sub-subclasses for improved discrimination in their classification of enzyme reactions. The results also indicate that mechanistic convergence of reaction steps is widespread, suggesting that quantitative measurement of mechanistic similarity can inform approaches for functional annotation. PMID:20300652

Almonacid, Daniel E; Yera, Emmanuel R; Mitchell, John B O; Babbitt, Patricia C

2010-03-01

195

NIST Organic Act National Institute of Standards and Technology Act  

E-print Network

concerns compete strongly in world markets. (3) Improvements in manufacturing and product technology dependNIST Organic Act National Institute of Standards and Technology Act SECTION 1. FINDINGS-being of the United States economy depends on a strong manufacturing base and requires continual improvements

Magee, Joseph W.

196

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 ...

197

Covalent enzyme immobilization on paramagnetic polyacrolein beads.  

PubMed

An optimized procedure of covalent glucose oxidase, urease, Bacillus subtilis alpha-amylase and Bacillus licheniformis alpha-amylase immobilization on paramagnetic, non-porous, polyacrolein beads is presented. The resulting insolubilized enzymes can be employed for extended periods of time without loss of activity. The conditions were optimized for maximizing the activity of the linked enzyme. Coated beads bearing up to 15 micrograms active enzyme/mg(beads) were obtained on reproducible basis. The paramagnetic feature of the particles facilitates the enzyme handling. In the magnetic field, the enzyme separation is fast and complete. Thus, the paramagnetic beads represent an excellent carrier for immobilized enzymes. PMID:8746190

Varlan, A R; Sansen, W; Van Loey, A; Hendrickx, M

1996-01-01

198

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

199

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); David H. Sherman (University of Michigan;Life Sciences Institute; Departments of Medicinal Chemistry, Chemistry, and Microbiology and Immunology)

2008-09-05

200

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

201

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

202

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

203

Enzyme Flexibility in Drosophila melanogaster  

Microsoft Academic Search

POLYMORPHISMS for genetically determined enzyme variants have been reported in humans1, Drosophila2 and several other groups of organisms, but there is no adequate explanation for their occurrence. Genetic polymorphisms can be maintained in numerous ways3, but Haldane4 and Mayr5 have emphasized that geographical or temporal changes in the environment could place a premium on metabolic flexibility and that selection for

John Gibson

1970-01-01

204

Enzymes of respiratory iron oxidation  

SciTech Connect

This report focuses on the progress made in three areas of research concerned with enzymes involved in respiratory iron oxidation. The three areas are as follows: development of an improved procedure for the routine large scale culture of iron oxidizing chemolithotrophs based on the in-situ electrolysis of the soluble iron in the growth medium; to perform iron oxidation kinetic studies on whole cells using the oxygen electrode; and to identify, separate, purify, and characterize the individual cellular components.

Blake, R. II.

1991-01-01

205

Myopathies due to enzyme deficiencies.  

PubMed

After the discovery in 1959 of myophosphorylase deficiency, at least 15 myopathies due to deficiency of enzymes involved in energy substrate utilization have been described. In this review two main categories of enzymopathies, glycogenosis and mitochondrial disorders, are discussed. Clinically, the patients with these categories of enzyme defects present two major syndromes: acute recurrent muscle impairment, generally related to exercise, associated with cramps and/or myoglobinuria; progressive muscular weakness and wasting eventually associated with signs of affected organs other than skeletal muscle. Defects of glycogen breakdown and of the first step of glycolysis are more frequently associated with acute exercise intolerance, such as in myophosphorylase and phosphofructokinase deficiencies, but may be associated with progressive muscle weakness and wasting, such as in acid maltase and debrancher enzyme deficiency. Clinical heterogeneity is common in these disorders, but a biochemical explanation for their different clinical expression is still lacking. Defects of the second step of glycolysis, phosphoglycerate kinase, phosphoglycerate mutase and lactate dehydrogenase deficiencies, have been discovered recently and are associated with exercise intolerance. The reason for muscle weakness and atrophy in glycogenosis is still unclear, although it has been suggested that excessive protein catabolism occurs in myophosphorylase, debrancher and acid maltase deficiencies. Myopathies due to deficiencies of mitochondrial enzymes are less well defined, as a group, than the glycogenoses. They are currently considered to fall into three main groups: defects of substrate utilization, such as carnitine palmitoyltransferase deficiency; defects of respiratory chain complexes, such as cytochrome-c-oxidase deficiency and defects of phosphorylation-respiration coupling, such as Luft's disease. Again, severe and benign exercise intolerance or progressive life-threatening myopathic syndromes may be the clinical expression of these disorders. Detailed biochemical and morphological studies of muscle biopsies are needed in these patients to obtain a definite diagnosis and prognosis, and to decide on eventual treatment. PMID:2934518

Cornelio, F; Di Donato, S

1985-01-01

206

Substrate Mediated Enzyme Prodrug Therapy  

PubMed Central

In this report, we detail Substrate Mediated Enzyme Prodrug Therapy (SMEPT) as a novel approach in drug delivery which relies on enzyme-functionalized cell culture substrates to achieve a localized conversion of benign prodrug(s) into active therapeutics with subsequent delivery to adhering cells or adjacent tissues. For proof-of-concept SMEPT, we use surface adhered micro-structured physical hydrogels based on poly(vinyl alcohol), ?-glucuronidase enzyme and glucuronide prodrugs. We demonstrate enzymatic activity mediated by the assembled hydrogel samples and illustrate arms of control over rate of release of model fluorescent cargo. SMEPT was not impaired by adhering cells and afforded facile time - and dose – dependent uptake of the in situ generated fluorescent cargo by hepatic cells, HepG2. With the use of a glucuronide derivative of an anticancer drug, SN-38, SMEPT afforded a decrease in cell viability to a level similar to that achieved using parent drug. Finally, dose response was achieved using SMEPT and administration of judiciously chosen concentration of SN-38 glucuronide prodrug thus revealing external control over drug delivery using drug eluting surface. We believe that this highly adaptable concept will find use in diverse biomedical applications, specifically surface mediated drug delivery and tissue engineering. PMID:23152927

Fejerskov, Betina; Zelikin, Alexander N.

2012-01-01

207

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

208

Inhibitory zinc sites in enzymes.  

PubMed

Several pathways increase the concentrations of cellular free zinc(II) ions. Such fluctuations suggest that zinc(II) ions are signalling ions used for the regulation of proteins. One function is the inhibition of enzymes. It is quite common that enzymes bind zinc(II) ions with micro- or nanomolar affinities in their active sites that contain catalytic dyads or triads with a combination of glutamate (aspartate), histidine and cysteine residues, which are all typical zinc-binding ligands. However, for such binding to be physiologically significant, the binding constants must be compatible with the cellular availability of zinc(II) ions. The affinity of inhibitory zinc(II) ions for receptor protein tyrosine phosphatase ? is particularly high (K i = 21 pM, pH 7.4), indicating that some enzymes bind zinc almost as strongly as zinc metalloenzymes. The competitive pattern of zinc inhibition for this phosphatase implicates its active site cysteine and nearby residues in the coordination of zinc. Quantitative biophysical data on both affinities of proteins for zinc and cellular zinc(II) ion concentrations provide the basis for examining the physiological significance of inhibitory zinc-binding sites in proteins and the role of zinc(II) ions in cellular signalling. Regulatory functions of zinc(II) ions add a significant level of complexity to biological control of metabolism and signal transduction and embody a new paradigm for the role of transition metal ions in cell biology. PMID:23456096

Maret, Wolfgang

2013-04-01

209

Equality Act 2010 Guidance on  

E-print Network

discrimination mean in this chapter? Other unlawful conduct Liability for acts of employees and agents Liability? Chapter 4 Direct discrimination Introduction What the Act says What is `less favourable' treatment is it lawful to treat a person more favourably? Discrimination because of pregnancy and maternity 35 35 36 37

Mottram, Nigel

210

Workforce Investment Act of 1998.  

ERIC Educational Resources Information Center

This document provides an overview of the Workforce Investment Act, which provides the framework for a national work force preparation and employment system designed to meet simultaneously the needs of the nation's businesses and of job seekers wishing to further their careers. The document begins with a brief summary of the act's five titles,…

Employment and Training Administration (DOL), Washington, DC.

211

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

212

Family Educational Rights & Privacy Act  

E-print Network

FERPA Family Educational Rights & Privacy Act #12;What is FERPA? FERPA is the Family Educational Rights and Privacy Act of 1974. The law was designed to protect the privacy of a student's education: student's name, local and permanent address, telephone and email, dates off attendance at IIT, positions

Heller, Barbara

213

Nitrate reductase, a nitric oxide-producing enzyme: induction by pathogen signals  

Microsoft Academic Search

Nitric oxide (NO) is believed to act as an effector for defense signaling in plant cells. Nitrate reductase (NR) is one of the NO-producing enzymes in plants. Here, we report that infection of Phytophthora infestans, the fungal pathogen of potato late blight, into potato tubers caused a transient increase in the NR transcript in an incompatible, but not a compatible,

Ayako Yamamoto; Shinpei Katou; Hirofumi Yoshioka; Noriyuki Doke; Kazuhito Kawakita

2003-01-01

214

Enantioselective reactions catalyzed by synthetic enzymes. A model for chemical evolution  

Microsoft Academic Search

Polyleucines of various lengths act as enantioselective catalysts in the aldol condensation between cyclohexanone and various aromatic aldehydes. Polyleucine and other polyamino acids behave as synthetic enzymes in the epoxidation of chalcone and other electron-deficient alkenes. Both reactions are of considerable prebiotic significance.

Stefano Colonna; Dario Perdicchia; Ernesto Di Mauro

2009-01-01

215

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

216

ENZYME DEGRADATION OF CHIRAL ORGANIC PHOSPHORUS INSECTICIDES  

EPA Science Inventory

Chiral organic phosphorus pesticides (OPs) are expected to be biologically degraded enantioselectively by endogenous enzymes. Various chiral Ops were treated with the enzyme phosphotriesterase (PTE) obtained from partially purified extracts of Escherichia coli strain DH-5- carryi...

217

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;); A. Malcolm Campbell (Davidson College;)

1999-01-01

218

Immobilized Enzymes and the Food Processing Industry.  

National Technical Information Service (NTIS)

Enzymes have long been recognized as the most efficient catalysts known to man. Unlike most industrial catalysts which operate under extreme conditions of temperature and/or pressure, enzymes work most efficiently at room temperature. The mechanism of enz...

P. F. Greenfield, R. L. Lawrence

1974-01-01

219

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

220

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...

221

Development of silica gel-supported modified macroporous chitosan membranes for enzyme immobilization and their characterization analyses.  

PubMed

The present work was aimed at developing stability enhanced silica gel-supported macroporous chitosan membrane for immobilization of enzymes. The membrane was surface modified using various cross-linking agents for covalent immobilization of enzyme Bovine serum albumin. The results of FT-IR, UV-vis, and SEM analyses revealed the effect of cross-linking agents and confirmed the formation of modified membranes. The presence of silica gel as a support could provide a large surface area, and therefore, the enzyme could be immobilized only on the surface, and thus minimized the diffusion limitation problem. The resultant enzyme immobilized membranes were also characterized based on their activity retention, immobilization efficiency, and stability aspects. The immobilization process increased the activity of immobilized enzyme even higher than that of total (actual) activity of native enzyme. Thus, the obtained macroporous chitosan membranes in this study could act as a versatile host for various guest molecules. PMID:24846556

Yang, Wen-Yi; Thirumavalavan, Munusamy; Malini, Madasamy; Annadurai, Gurusamy; Lee, Jiunn-Fwu

2014-07-01

222

The Differentiation of Pigmentation in Flower Parts, IV. Flavonoid Elaborating Enzymes From Petals of Impatiens balsamina s.  

PubMed

Extracts of the flower petals of Impatiens balsamina L. contain enzymes which catalyze the glycosylation of phenolic compounds. Enzymes have been extracted which glycosylate hydroquinone to arbutin and at least 3 different flavonols to the 3-monoglucoside. The hydroquinone glucosylating enzyme is similar to enzymes previously described except that it requires an unidentified low molecular weight cofactor. The glucosylation of flavonols follows normal enzyme kinetics; it requires a nucleotide diphosphate glucose donor for activity, and is made more evident by the presence of glucono-1:5-lactone, an inhibitor of endogenous glucosidases. It is suggested that the flavonol glucosylating enzyme acts naturally to glucosylate a precursor of both flavonols and anthocyanins to the 3-monoglucoside. The only elaboration of an anthocyanin observed with petal extracts was an acylation of pelargonidin-3-monoglucoside. PMID:16656918

Miles, C D; Hagen, C W

1968-09-01

223

13 CFR 107.115 - 1940 Act and 1980 Act Companies.  

Code of Federal Regulations, 2010 CFR

...false 1940 Act and 1980 Act Companies. 107.115 Section 107... SMALL BUSINESS INVESTMENT COMPANIES Qualifying for an SBIC License Organizing An Sbic § 107.115 1940 Act and 1980 Act Companies. A 1940 Act or...

2010-01-01

224

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

... Architectural Barriers Act and the Americans with Disabilities Act. 570.614... Architectural Barriers Act and the Americans with Disabilities Act. (a...general type buildings). (b) The Americans with Disabilities Act (42...

2014-04-01

225

Antioxidative capacity and enzyme activity in Haematococcus pluvialis cells exposed to superoxide free radicals  

NASA Astrophysics Data System (ADS)

The antioxidative capacity of astaxanthin and enzyme activity of reactive oxygen eliminating enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) were studied in three cell types of Haematococcus pluvialis exposed to high concentrations of a superoxide anion radical (O{2/-}). The results show that defensive enzymes and astaxanthin-related mechanisms were both active in H. pluvialis during exposure to reactive oxygen species (ROS) such as O{2/-}. Astaxanthin reacted with ROS much faster than did the protective enzymes, and had the strongest antioxidative capacity to protect against lipid peroxidation. The defensive mechanisms varied significantly between the three cell types and were related to the level of astaxanthin that had accumulated in those cells. Astaxanthin-enriched red cells had the strongest antioxidative capacity, followed by brown cells, and astaxanthin-deficient green cells. Although there was no significant increase in expression of protective enzymes, the malondialdehyde (MDA) content in red cells was sustained at a low level because of the antioxidative effect of astaxanthin, which quenched O{2/-} before the protective enzymes could act. In green cells, astaxanthin is very low or absent; therefore, scavenging of ROS is inevitably reliant on antioxidative enzymes. Accordingly, in green cells, these enzymes play the leading role in scavenging ROS, and the expression of these enzymes is rapidly increased to reduce excessive ROS. However, because ROS were constantly increased in this study, the enhance enzyme activity in the green cells was not able to repair the ROS damage, leading to elevated MDA content. Of the four defensive enzymes measured in astaxanthin-deficient green cells, SOD eliminates O{2/-}, POD eliminates H2O2, which is a by-product of SOD activity, and APX and CAT are then initiated to scavenge excessive ROS.

Liu, Jianguo; Zhang, Xiaoli; Sun, Yanhong; Lin, Wei

2010-01-01

226

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

227

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

228

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 resolution crystal structures of M -activated enzymes, which have become available only over the last decade

Di Cera, Enrico

229

Kemp elimination catalysts by computational enzyme design  

E-print Network

ARTICLES Kemp elimination catalysts by computational enzyme design Daniela Ro¨thlisberger1 *, Olga for creating new enzymes, and we anticipate the creation of a wide range of useful new catalysts in the future. Naturally occurring enzymes are extraordinarily efficient catalysts1 . They bind their substrates in a well

Tawfik, Dan S.

230

Microorganisms detected by enzyme-catalyzed reaction  

NASA Technical Reports Server (NTRS)

Enzymes detect the presence of microorganisms in soils. The enzyme lysozymi is used to release the enzyme catalase from the microorganisms in a soil sample. The catalase catalyzes the decomposition of added hydrogen peroxide to produce oxygen which is detected manometrically. The partial pressure of the oxygen serves as an index of the samples bacteria content.

Vango, S. P.; Weetall, H. H.; Weliky, N.

1966-01-01

231

Enzymes with Molecular Tunnels FRANK M. RAUSHEL,*,  

E-print Network

Enzymes with Molecular Tunnels FRANK M. RAUSHEL,*, JAMES B. THODEN, AND HAZEL M. HOLDEN become feasible to examine complicated protein structures at high resolution. For those enzymes understanding of molecular tunnels ob- served in various enzyme systems. Introduction A revolution in biological

Holden, Hazel

232

Probing Product Binding in Cellulase Enzymes  

E-print Network

Probing Product Binding in Cellulase Enzymes Simulations uncover potential new strategies for increasing the desired effects of enzymes for biofuels. Large-scale computer simulations offer a new interpretation for the discrepancy in experimentally measured product inhibition constants in cellulase enzymes

233

Enzyme Nanoparticles-Based Electronic Biosensor  

Microsoft Academic Search

A novel method for fabricating electronic biosensors based on coupling enzyme nanoparticles and self assembly technology is illustrated. Redox horseradish peroxidase nanoparticles were prepared by desolvation with ethanol and subsequent crosslinking with glutaraldehyde. The cross-linked enzyme nanoparticles were functionalized by cysteine to introduce thiol groups on the nanoparticle surface. Immobilized enzyme nanoparticle on the gold electrode by self-assembly kept redox

Guodong Liu; Yuehe Lin; V. Ostatna; Joseph Wang

2005-01-01

234

Immobilization of Enzymes in Polymer Supports.  

ERIC Educational Resources Information Center

Two experiments in which an enzyme is immobilized onto a polymeric support are described. The experiments (which also demonstrate two different polymer preparations) involve: (1) entrapping an enzyme in an acrylamide polymer; and (2) reacting the amino groups on the enzyme's (esterase) lysine residues with an activated polymer. (JN)

Conlon, Hugh D.; Walt, David R.

1986-01-01

235

Covalent enzyme immobilization on paramagnetic polyacrolein beads  

Microsoft Academic Search

An optimized procedure of covalent glucose oxidase, urease, Bacillus subtilis ?-amylase and Bacillus licheniformis ?-amylase immobilization on paramagnetic, non-porous, polyacrolein beads is presented. The resulting insolubilized enzymes can be employed for extended periods of time without loss of activity. The conditions were optimized for maximizing the activity of the linked enzyme. Coated beads bearing up to 15 ?gactive enzyme\\/mgbeads were

Ann Van Loey; Marc Hendrickx

1996-01-01

236

The Human But Not the Xenopus RNA-editing Enzyme ADAR1 Has an Atypical Nuclear Localization Signal and Displays the Characteristics of a Shuttling Protein  

Microsoft Academic Search

The RNA-editing enzyme ADAR1 (adenosine deaminase that acts on RNA) is a bona fide nuclear enzyme that has been cloned from several vertebrate species. Putative nuclear localization signals (NLSs) have been identified in the aminoterminal regions of both human and Xenopus ADAR1. Here we show that neither of these predicted NLSs is biologically active. Instead, we could identify a short

Christian R. Eckmann; Andrea Neunteufl; Lydia Pfaffstetter; Michael F. Jantsch

237

Distinct in vivo roles for double-stranded RNA-binding domains of the Xenopus RNA-editing enzyme ADAR1 in chromosomal targeting  

Microsoft Academic Search

he RNA-editing enzyme adenosine deaminase that acts on RNA (ADAR1) deaminates adenosines to inosines in double-stranded RNA substrates. Currently, it is not clear how the enzyme targets and discriminates different substrates in vivo . However, it has been shown that the deaminase domain plays an important role in distin- guishing various adenosines within a given substrate RNA in vitro .

Michael Doyle; Michael F. Jantsch

2003-01-01

238

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

239

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 Tryptic digestion uu u_ 182 Ereptic digestion u n _ 186 Carbohydrate-splitting enzymes _ 184 Amylase _ 184 enzymes in representatives throughout the vertebrate series. It would be of value to know if differences

240

Enzyme Analysis to Determine Glucose Content  

NASA Astrophysics Data System (ADS)

Enzyme analysis is used for many purposes in food science and technology. Enzyme activity is used to indicate adequate processing, to assess enzyme preparations, and to measure constituents of foods that are enzyme substrates. In this experiment, the glucose content of corn syrup solids is determined using the enzymes, glucose oxidase and peroxidase. Glucose oxidase catalyzes the oxidation of glucose to form hydrogen peroxide (H2O2), which then reacts with a dye in the presence of peroxidase to give a stable colored product.

Carpenter, Charles; Ward, Robert E.

241

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.

2002-01-01

242

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.

2007-07-20

243

Kenji Soda--researching enzymes with the spirit of an alpinist.  

PubMed

Like an alpinist continuously seeking virgin peaks to climb, Kenji Soda has investigated a variety of unique enzymes for which there was little or no information available; and by doing so he opened up a variety of new fields in enzyme science and technology. In particular, he has promoted the study of enzymes requiring vitamin B-derived cofactors such as FAD, NAD(P) and pyridoxal 5'-phosphate, shedding light on their reaction mechanisms, enzymological properties, crystal structures and potential practical applications. Highlighted in this review are the studies of enzymes acting on d-amino acids and sulphur/selenium-containing amino acids and those from thermophilic and psychrophilic bacteria. PMID:20924059

Yoshimura, Toru; Mihara, Hisaaki; Ohshima, Toshihisa; Tanizawa, Katsuyuki

2010-10-01

244

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

245

MAJOR PROGRAMS ACTG Acting [BFA  

E-print Network

MAJOR PROGRAMS ACTG Acting [BFA] AFST Africana Studies [BA] AMST American Studies [BA] ANCS Ancient Africana Studies AMST American Studies ANCS Ancient Studies ANTH Anthropology APPO Applied Politics (majors

Maryland, Baltimore County, University of

246

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

247

Enzyme Mediated Synthesis of a Semiconducting Metal Oxide  

E-print Network

specific enzymes thermal denaturation temperature. Urease isof the enzyme increases with increasing temperature. Theand temperature conditions compared with the normal operating conditions of the enzyme

Johnson, John Michael

2012-01-01

248

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; Wallace, Andrew

249

Cell-free translation of biofuel enzymes.  

PubMed

In nature, bacteria and fungi are able to utilize recalcitrant plant materials by secreting a diverse set of enzymes. While genomic sequencing efforts offer exhaustive lists of genes annotated as potential polysaccharide-degrading enzymes, biochemical and functional characterizations of the encoded proteins are still needed to realize the full potential of this natural genomic diversity. This chapter outlines an application of wheat germ cell-free translation to the study of biofuel enzymes using genes from Clostridium thermocellum, a model cellulolytic organism. Since wheat germ extract lacks enzymatic activities that can hydrolyze insoluble polysaccharide substrates and is likewise devoid of enzymes that consume the soluble sugar products, the cell-free translation reactions provide a clean background for production and study of the reactions of biofuel enzymes. Examples of assays performed with individual enzymes or with small sets of enzymes obtained directly from cell-free translation are provided. PMID:24395410

Takasuka, Taichi E; Walker, Johnnie A; Bergeman, Lai F; Vander Meulen, Kirk A; Makino, Shin-ichi; Elsen, Nathaniel L; Fox, Brian G

2014-01-01

250

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. Résumé DISTRIBUTION DES ENZYMES DANS LES ORGANES DE L'OIE. EFFETS DE L'ENGRAISSEMENT SUR LES ENZYMES HÃ?PATIQUES. ― La distribution de quelques enzymes dans les organes de l'oie a été

Paris-Sud XI, Université de

251

Peptidoglycan remodeling by the coordinated action of multispecific enzymes.  

PubMed

The peptidoglycan (PG) cell wall constitutes the main defense barrier of bacteria against environmental insults and acts as communication interface. The biochemistry of this macromolecule has been well characterized throughout the years but recent discoveries have unveiled its chemical plasticity under environmental stresses. Non-canonical D-amino acids (NCDAA) are produced and released to the extracellular media by diverse bacteria. Such molecules govern cell wall adaptation to challenging environments through their incorporation into the polymer, a widespread capability among bacteria that reveals the inherent catalytic plasticity of the enzymes involved in the cell wall metabolism. Here, we analyze the recent structural and biochemical characterization of Bsr, a new family of broad spectrum racemases able to generate a wide range of NCDAA. We also discuss the necessity of a coordinated action of PG multispecific enzymes to generate adequate levels of modification in the murein sacculus. Finally, we also highlight how this catalytic plasticity of NCDAA-incorporating enzymes has allowed the development of new revolutionary methodologies for the study of PG modes of growth and in vivo dynamics. PMID:24799190

Alvarez, Laura; Espaillat, Akbar; Hermoso, Juan A; de Pedro, Miguel A; Cava, Felipe

2014-06-01

252

DNA glycosylase enzymes induced during chemical adaptation of M. luteus.  

PubMed Central

Five peaks of DNA glycosylase activity showing a preference for MNNG alkylated DNA have been identified from extracts of adapted M. luteus. They are numerically designated as GI to GV in order of their decreasing molecular weights. The first two of these peaks have been highly purified. GI, is a constitutive heat labile protein, 35% stimulated by the presence of 50 mM NaCl, acts exclusively on 3 MeA residues in alkylated DNA, 60-70% inhibited by the presence of 2 mM free 3MeA and has been designated as 3MeA DNA glycosylase enzyme. GII, which is an inducible protein, is heat stable, 28% inhibited by the presence of 50 mM NaCl, removes 3MeA, 3MeG, 7MeA & 7MeG with different efficiency, and has been designated as 3,7 methylpurine DNA glycosylase enzyme. The rate of release of 3 methylpurines is 30 times that of 7MeG. There is no activity of either enzyme on O2-MeC, O2-MeT, O4-MeT or O6-MeG. The apparent molecular weights of GI and GII proteins are 28 Kd and 22 Kd respectively. PMID:3628000

Riazuddin, S; Athar, A; Ahmed, Z; Lali, S M; Sohail, A

1987-01-01

253

Inactivation of enzymes within spores of Bacillus megaterium ATCC 19213 by hydroperoxides.  

PubMed

The organic hydroperoxides t-butyl hydroperoxide, cumene hydroperoxide, and peracetic acid were found to act similarly to hydrogen peroxide in causing inactivation of enzymes within intact spores of bacillus megaterium ATCC 19213 concomitant with mortality. Spores treated with lethal levels of the agents were germinated and permeabilized for enzyme assays. The hierarchy of sensitivities among enolase, glucose-6-phosphate dehydrogenase (G6Pdh), and pyruvate kinase to inactivation varied somewhat with the specific hydroperoxide used, possibly because of the differences in the types of radicals generated. However, each agent inactivated each of the enzymes, albeit at different rates. Comparative assessments of enzyme inactivation by lethal levels of H2O2 or by moist heat showed that some enzymes, such as G6Pdh, are highly sensitive to inactivation, while others, such as ATPases, are much more resistant. The enzymes G6Pdh and aldolase were highly sensitive to hydroperoxide inactivation and also to moist heat, while pyruvate kinase was much more sensitive to hydroperoxides than to moist heat. Our overall interpretation of the findings is that hydroperoxides and moist heat can produce cumulative damage to sensitive enzymes within spores, which progressively diminishes the capacities of the cells to undergo the outgrowth required for return to vegetative life. PMID:9741972

Palop, A; Rutherford, G C; Marquis, R E

1998-05-01

254

Recombinant Human Angiotensin-Converting Enzyme 2 as a New Renin-Angiotensin System Peptidase for Heart Failure Therapy  

Microsoft Academic Search

Angiotensin-converting enzyme 2 (ACE2) is a monocarboxypeptidase that metabolizes several peptides, including the degradation\\u000a of angiotensin (Ang) II, a peptide with vasoconstrictive\\/proliferative effects, to generate Ang 1-7, which exerts vasodilatory\\/antiproliferative\\u000a actions by acting through its receptor Mas. ACE2 is a multifunctional enzyme, and its actions on other vasoactive peptides,\\u000a including the apelin-13 and apelin-17 peptides, also can contribute to its

Gavin Y. Oudit; Josef M. Penninger

2011-01-01

255

Effects of redox cycling compounds on glutathione content and activity of glutathione-related enzymes in rainbow trout liver  

Microsoft Academic Search

In fish, as in other aerobic organisms, glutathione and glutathione-related enzymes are important components in the defences against oxidative stress. To study if hepatic glutathione levels and\\/or activities of glutathione-related enzymes can act as indicators of oxidative stress in fish, we injected rainbow trout (Oncorhynchus mykiss) intraperitoneally with paraquat (PQ), menadione (MD), naphthazarin (DHNQ), or ?-naphthoflavone (?-NF), all known to

Eir??kur Stephensen; Joachim Sturve; Lars Förlin

2002-01-01

256

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

257

Enzyme analysis of Schistosoma haematobium*  

PubMed Central

Results are reported of enzyme analyses, by isoelectric focusing in polyacrylamide gels, of adult Schistosoma haematobium worms derived from 22 isolates originating from 13 countries. Polymorphisms have been identified in the glucose-6-phosphate dehydrogenase (G6PD) and phosphoglucomutase (PGM) systems. Certain forms appear to be restricted in their geographical distribution and their occurrence outside their usual areas suggests human population movements resulting in mixing of parasite strains. The possible implications of minor variations in some PGM patterns and the apparent absence of heteropolymer fractions in presumed G6PD heterozygotes are discussed. The use of the technique to detect natural multiple miracidial infections in snails is reported and discussed. ImagesFig. 1 PMID:6222843

Wright, C. A.; Ross, G. C.

1983-01-01

258

Encapsulation of Enzymes and Peptides  

NASA Astrophysics Data System (ADS)

A large part of formulated peptides and proteins, e.g., enzymes used as food ingredients, are formulated in a liquid form. Often, they are dissolved in water to which glycerol or sorbitol is added to reduce the water activity of the liquid, thus reducing the change of microbial growth. Still, there are reasons to formulate them in a solid form. Often, these reasons are stability, since a dry formulation is often much better than liquid formulations, and less transportation cost, since less mass is transported if one gets rid of the liquid; however, most of the times, the reason is that the product is mixed with a solid powder. Here, a liquid addition would lead to lump formation.

Meesters, Gabrie M. H.

259

7 CFR 1260.128 - Act.  

...MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE BEEF PROMOTION AND RESEARCH Beef Promotion and Research Order Definitions § 1260.128 Act. Act means the Beef Promotion and Research Act of 1985, Title XVI,...

2014-01-01

260

7 CFR 1260.128 - Act.  

Code of Federal Regulations, 2012 CFR

...MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE BEEF PROMOTION AND RESEARCH Beef Promotion and Research Order Definitions § 1260.128 Act. Act means the Beef Promotion and Research Act of 1985, Title XVI,...

2012-01-01

261

7 CFR 1260.128 - Act.  

Code of Federal Regulations, 2011 CFR

...MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE BEEF PROMOTION AND RESEARCH Beef Promotion and Research Order Definitions § 1260.128 Act. Act means the Beef Promotion and Research Act of 1985, Title XVI,...

2011-01-01

262

7 CFR 1260.128 - Act.  

Code of Federal Regulations, 2010 CFR

...MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE BEEF PROMOTION AND RESEARCH Beef Promotion and Research Order Definitions § 1260.128 Act. Act means the Beef Promotion and Research Act of 1985, Title XVI,...

2010-01-01

263

7 CFR 1260.128 - Act.  

Code of Federal Regulations, 2013 CFR

...MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE BEEF PROMOTION AND RESEARCH Beef Promotion and Research Order Definitions § 1260.128 Act. Act means the Beef Promotion and Research Act of 1985, Title XVI,...

2013-01-01

264

7 CFR 1207.302 - Act.  

Code of Federal Regulations, 2010 CFR

...DEPARTMENT OF AGRICULTURE POTATO RESEARCH AND PROMOTION PLAN Potato Research and Promotion Plan Definitions... Act. Act means the Potato Research and Promotion Act, Title III of Public Law 91-670, 91st Congress,...

2010-01-01

265

7 CFR 1207.302 - Act.  

Code of Federal Regulations, 2011 CFR

...DEPARTMENT OF AGRICULTURE POTATO RESEARCH AND PROMOTION PLAN Potato Research and Promotion Plan Definitions... Act. Act means the Potato Research and Promotion Act, Title III of Public Law 91-670, 91st Congress,...

2011-01-01

266

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

267

7 CFR 1220.600 - Act.  

Code of Federal Regulations, 2012 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...

2012-01-01

268

7 CFR 1220.600 - Act.  

Code of Federal Regulations, 2011 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...

2011-01-01

269

7 CFR 1220.600 - Act.  

...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...

2014-01-01

270

7 CFR 1220.600 - Act.  

Code of Federal Regulations, 2013 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...

2013-01-01

271

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

272

7 CFR 917.2 - Act.  

Code of Federal Regulations, 2011 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...

2011-01-01

273

7 CFR 985.2 - Act.  

...AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE MARKETING ORDER REGULATING THE HANDLING OF SPEARMINT OIL PRODUCED IN THE FAR WEST Order Regulating Handling Definitions § 985.2 Act. Act means Public Act...

2014-01-01

274

7 CFR 985.2 - Act.  

Code of Federal Regulations, 2012 CFR

...Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE MARKETING ORDER REGULATING THE HANDLING OF SPEARMINT OIL PRODUCED IN THE FAR WEST Order Regulating Handling Definitions § 985.2 Act. Act means Public Act...

2012-01-01

275

7 CFR 985.2 - Act.  

Code of Federal Regulations, 2013 CFR

...AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE MARKETING ORDER REGULATING THE HANDLING OF SPEARMINT OIL PRODUCED IN THE FAR WEST Order Regulating Handling Definitions § 985.2 Act. Act means Public Act...

2013-01-01

276

7 CFR 985.2 - Act.  

Code of Federal Regulations, 2010 CFR

...Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE MARKETING ORDER REGULATING THE HANDLING OF SPEARMINT OIL PRODUCED IN THE FAR WEST Order Regulating Handling Definitions § 985.2 Act. Act means Public Act...

2010-01-01

277

7 CFR 985.2 - Act.  

Code of Federal Regulations, 2011 CFR

...Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE MARKETING ORDER REGULATING THE HANDLING OF SPEARMINT OIL PRODUCED IN THE FAR WEST Order Regulating Handling Definitions § 985.2 Act. Act means Public Act...

2011-01-01

278

7 CFR 906.2 - Act.  

Code of Federal Regulations, 2010 CFR

...Marketing Agreements and 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...

2010-01-01

279

7 CFR 966.2 - Act.  

Code of Federal Regulations, 2011 CFR

... AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating Handling Definitions § 966.2 Act. Act means Public Act No. 10, 73d...

2011-01-01

280

7 CFR 926.2 - Act.  

Code of Federal Regulations, 2010 CFR

...DEPARTMENT OF AGRICULTURE DATA COLLECTION, REPORTING AND RECORDKEEPING REQUIREMENTS APPLICABLE TO CRANBERRIES NOT SUBJECT TO THE CRANBERRY MARKETING ORDER § 926.2 Act. Act means Public Act No. 10, 73d Congress [May 12,...

2010-01-01

281

7 CFR 966.2 - Act.  

Code of Federal Regulations, 2012 CFR

...Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating Handling Definitions § 966.2 Act. Act means Public Act No. 10, 73d...

2012-01-01

282

Industrial Fungal Enzymes: An Occupational Allergen Perspective  

PubMed Central

Occupational exposure to high-molecular-weight allergens is a risk factor for the development and pathogenesis of IgE-mediated respiratory disease. In some occupational environments, workers are at an increased risk of exposure to fungal enzymes used in industrial production. Fungal enzymes have been associated with adverse health effects in the work place, in particular in baking occupations. Exposure-response relationships have been demonstrated, and atopic workers directly handling fungal enzymes are at an increased risk for IgE-mediated disease and occupational asthma. The utilization of new and emerging fungal enzymes in industrial production will present new occupational exposures. The production of antibody-based immunoassays is necessary for the assessment of occupational exposure and the development of threshold limit values. Allergen avoidance strategies including personal protective equipment, engineering controls, protein encapsulation, and reduction of airborne enzyme concentrations are required to mitigate occupational exposure to fungal enzymes. PMID:21747869

Green, Brett J.; Beezhold, Donald H.

2011-01-01

283

Stabilized enzymes in continuous gas phase reactions  

SciTech Connect

We are assessing the utility of enzymes to catalyze reactions in a continuous gas phase reactor. First, alcohol dehydrogenase has been used to oxidize an unsaturated alcohol, 3-methyl-2-buten-1-ol (UOL), to the corresponding unsaturated aldehyde, 3-methyl-2-butenal (UAL). Cofactor NAD{sup +} was regenerated by concomitant acetone reduction to isopropyl alcohol. Second, organophosphorus hydrolase (OPH) has been used to hydrolyze pesticide vapors. In order to control enzyme hydration level, enzyme water adsorption isotherms at different temperature have been studied. Huttig`s isotherm model has been found suitable to describe adsorption behavior. The influence of enzyme hydration level, enzyme loading on glass beads, reaction temperature and flow rate on enzymatic reaction rate and biocatalyst stability were investigated. Reaction kinetics were studied and a kinetic model was proposed. We will also report our attempts to further stabilize enzymes for use in gas reactions by incorporating them into polymer matrices.

Yang, Fangxiao; LeJeune, K.; Yang, Zhen [Univ. of Pittsburgh, PA (United States)] [and others

1995-12-01

284

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

285

Understanding enzyme catalysis using computer simulation  

SciTech Connect

Enzymes catalyze biochemical reactions with remarkable specificity and efficiency, usually under physiological conditions. Computer simulation is a powerful tool for understanding enzyme catalytic mechanisms, particularly in cases where standard experimental techniques may be of limited utility. Here, we present an overview of the application of computer simulation techniques to understanding enzyme catalytic mechanisms. Examples using quantum chemical methods, as well as combined quantum mechanical/classical mechanical approaches, are provided.

Parks, Jerry M [ORNL; Imhof, Petra [ORNL; Smith, Jeremy C [ORNL

2010-01-01

286

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

287

Self-acting shaft seals  

NASA Technical Reports Server (NTRS)

Self-acting seals are described in detail. The mathematical models for obtaining a seal force balance and the equilibrium operating film thickness are outlined. Particular attention is given to primary ring response (seal vibration) to rotating seat face runout. This response analysis reveals three different vibration models with secondary seal friction being an important parameter. Leakage flow inlet pressure drop and affects of axisymmetric sealing face deformations are discussed. Experimental data on self-acting face seals operating under simulated gas turbine conditions are given. Also a spiral groove seal design operated to 244 m/sec (800 ft/sec) is described.

Ludwig, L. P.

1978-01-01

288

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

289

7 CFR 1220.101 - Act.  

Code of Federal Regulations, 2012 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...

2012-01-01

290

7 CFR 1220.101 - Act.  

...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...

2014-01-01

291

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

292

7 CFR 1220.101 - Act.  

Code of Federal Regulations, 2011 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...

2011-01-01

293

7 CFR 1220.101 - Act.  

Code of Federal Regulations, 2013 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...

2013-01-01

294

7 CFR 1215.1 - Act.  

Code of Federal Regulations, 2010 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE POPCORN PROMOTION, RESEARCH, AND CONSUMER INFORMATION Popcorn Promotion, Research, and Consumer Information... § 1215.1 Act. Act means the Popcorn Promotion, Research, and Consumer...

2010-01-01

295

7 CFR 1215.1 - Act.  

Code of Federal Regulations, 2013 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE POPCORN PROMOTION, RESEARCH, AND CONSUMER INFORMATION Popcorn Promotion, Research, and Consumer Information... § 1215.1 Act. Act means the Popcorn Promotion, Research, and Consumer...

2013-01-01

296

7 CFR 1215.1 - Act.  

...COMMODITIES), DEPARTMENT OF AGRICULTURE POPCORN PROMOTION, RESEARCH, AND CONSUMER INFORMATION Popcorn Promotion, Research, and Consumer Information... § 1215.1 Act. Act means the Popcorn Promotion, Research, and Consumer...

2014-01-01

297

7 CFR 1215.1 - Act.  

Code of Federal Regulations, 2012 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE POPCORN PROMOTION, RESEARCH, AND CONSUMER INFORMATION Popcorn Promotion, Research, and Consumer Information... § 1215.1 Act. Act means the Popcorn Promotion, Research, and Consumer...

2012-01-01

298

7 CFR 1215.1 - Act.  

Code of Federal Regulations, 2011 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE POPCORN PROMOTION, RESEARCH, AND CONSUMER INFORMATION Popcorn Promotion, Research, and Consumer Information... § 1215.1 Act. Act means the Popcorn Promotion, Research, and Consumer...

2011-01-01

299

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

300

Zymography methods for visualizing hydrolytic enzymes.  

PubMed

Zymography is a technique for studying hydrolytic enzymes on the basis of substrate degradation. It is a powerful, but often misinterpreted, tool yielding information on potential hydrolytic activities, enzyme forms and the locations of active enzymes. In this Review, zymography techniques are compared in terms of advantages, limitations and interpretations. With in gel zymography, enzyme forms are visualized according to their molecular weights. Proteolytic activities are localized in tissue sections with in situ zymography. In vivo zymography can pinpoint proteolytic activity to sites in an intact organism. Future development of novel substrate probes and improvement in detection and imaging methods will increase the applicability of zymography for (reverse) degradomics studies. PMID:23443633

Vandooren, Jennifer; Geurts, Nathalie; Martens, Erik; Van den Steen, Philippe E; Opdenakker, Ghislain

2013-03-01

301

Enzyme reactor design under thermal inactivation.  

PubMed

Temperature is a very relevant variable for any bioprocess. Temperature optimization of bioreactor operation is a key aspect for process economics. This is especially true for enzyme-catalyzed processes, because enzymes are complex, unstable catalysts whose technological potential relies on their operational stability. Enzyme reactor design is presented with a special emphasis on the effect of thermal inactivation. Enzyme thermal inactivation is a very complex process from a mechanistic point of view. However, for the purpose of enzyme reactor design, it has been oversimplified frequently, considering one-stage first-order kinetics of inactivation and data gathered under nonreactive conditions that poorly represent the actual conditions within the reactor. More complex mechanisms are frequent, especially in the case of immobilized enzymes, and most important is the effect of catalytic modulators (substrates and products) on enzyme stability under operation conditions. This review focuses primarily on reactor design and operation under modulated thermal inactivation. It also presents a scheme for bioreactor temperature optimization, based on validated temperature-explicit functions for all the kinetic and inactivation parameters involved. More conventional enzyme reactor design is presented merely as a background for the purpose of highlighting the need for a deeper insight into enzyme inactivation for proper bioreactor design. PMID:12693444

Illanes, Andrés; Wilson, Lorena

2003-01-01

302

Potential of enzymes for wood debarking  

SciTech Connect

The effect of enzymatic pretreatment on the energy consumption of wood debarking was studied on the laboratory scale using enzymes to degrade the cambial layer. The energy consumed in debarking spruce was decreased as much as 80% after pretreatment with pectinolytic enzymes. In addition to polygalacturonase activity, pectin lyase and xylanase activities were also present in the most efficient enzyme preparation. Due to the complex composition of the cambium and inner phloem, these and other enzymes that hydrolyze the various inner bark components are probably needed for efficient debarking.

Raettoe, M.; Kantelinen, A.; Bailey, M.; Viikari, L. (VTT Biotechnical Lab., Espoo (Finland))

1993-02-01

303

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

Code of Federal Regulations, 2013 CFR

... false Clean Air Act and the Federal Water Pollution Control Act. ...2543.86 Clean Air Act and the Federal Water Pollution Control Act. ...pursuant to the Clean Air Act (42 U.S...the Federal Water Pollution Control Act as...

2013-10-01

304

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

Code of Federal Regulations, 2012 CFR

... false Clean Air Act and the Federal Water Pollution Control Act. ...2543.86 Clean Air Act and the Federal Water Pollution Control Act. ...pursuant to the Clean Air Act (42 U.S...the Federal Water Pollution Control Act as...

2012-10-01

305

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

Code of Federal Regulations, 2011 CFR

... false Clean Air Act and the Federal Water Pollution Control Act. ...2543.86 Clean Air Act and the Federal Water Pollution Control Act. ...pursuant to the Clean Air Act (42 U.S...the Federal Water Pollution Control Act as...

2011-10-01

306

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

Code of Federal Regulations, 2010 CFR

... false Clean Air Act and the Federal Water Pollution Control Act. ...2543.86 Clean Air Act and the Federal Water Pollution Control Act. ...pursuant to the Clean Air Act (42 U.S...the Federal Water Pollution Control Act as...

2010-10-01

307

UC Santa Cruz Acting Chancellor  

E-print Network

UC Santa Cruz Review Acting Chancellor George R. Blumenthal Vice Chancellor, University Relations of University Relations Carriage House University of California 1156 High Street Santa Cruz, CA 95064-1077 Voice: 831.459.2501 Fax: 831.459.5795 E-mail: jrburns@ucsc.edu Web: review.ucsc.edu Produced by UC Santa Cruz

Zhang, Yi

308

Freedom of Information Act Information  

E-print Network

Freedom of Information Act 2000 Information Request Form Reference no of request Please read the guidance accompanying this form and refer to the University's Freedom of Information publication scheme (http://www.admin.cam.ac.uk/univ/information/foi/foi_publication_scheme.pdf) before making

Talbot, James P.

309

The Indian Mineral Development Act.  

ERIC Educational Resources Information Center

Discusses the objectives of the Indian Mineral Development Act of 1982 (IMDA) and the possible effects it may have on Indian mineral development. Explains how the provisions of IMDA work to provide Indian tribes with greater flexibility for the development and sale of their mineral resources. (ML)

Houle, Antoinette

1986-01-01

310

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

311

Implementing the Clean Air Act  

Microsoft Academic Search

Early bans on coal use in London during the 14th century began a largely ineffective effort until the Clean Air Act Amendments of 1970 established a strong national program involving all levels of government. Until 1977, when new amendments were enacted, Congress struggled to develop acceptable tradeoffs between pollution control and industrial growth. States can now tailor their method of

Rothblatt

1980-01-01

312

The Proposed Environmental Justice Act: \\  

Microsoft Academic Search

This Comment addresses the concept of environmental racism, the tools that have been used to fight it, and the proposed Environmental Justice Act of 1993. Part II begins with an examination of the evidence minority communities have relied on as proof that environmental racism exists. The evidence contained in numerous articles clearly shows inequalities in the amounts of environmental and

Claire L. Hasler

1994-01-01

313

PHYSIOLOGY BY ACTING OUT CONCEPTS  

Microsoft Academic Search

ypically, classes in anatomy and physiology are taught via lecture and visual aids. This seems to work well for students who are primarily auditory and visual learners but not for those who learn better through kinesthetic experiences. This is the first report describing the use of improvisation to act out physiological concepts within an anatomy and physiology course. Improvisational techniques

Carolyn B. Yucha

314

The 1986 Act: Opportunities Missed.  

ERIC Educational Resources Information Center

This paper outlines the arrangements for assessing school leavers under Sections 5 and 6 of Great Britain's Disabled Persons Act, summarizes the results of research in Avon (England) following the lives of 50 people with severe learning difficulties just before and after they left school. Presents a model for individual and strategic planning to…

Madden, Phil

1993-01-01

315

Federal Black Lung Benefits Act  

Microsoft Academic Search

The basis for the filing of a civil action suit brought by a number of railroads against the Secretaries of Labor, Health and Human Services and the Treasury for declaratory and injunctive relief from certain provisions of the Federal Black Lung Benefit Act is set forth. The arguments that railroads are not liable for payment of benefits to their workers

Stallsmith; W. P. Jr

2009-01-01

316

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.

317

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

318

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

319

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

320

The Impact of Enzyme Orientation and Electrode Topology on the Catalytic Activity of Adsorbed Redox Enzymes  

PubMed Central

It is well established that the structural details of electrodes and their interaction with adsorbed enzyme influences the interfacial electron transfer rate. However, for nanostructured electrodes, it is likely that the structure also impacts on substrate flux near the adsorbed enzymes and thus catalytic activity. Furthermore, for enzymes converting macro-molecular substrates it is possible that the enzyme orientation determines the nature of interactions between the adsorbed enzyme and substrate and therefore catalytic rates. In essence the electrode may impede substrate access to the active site of the enzyme. We have tested these possibilities through studies of the catalytic performance of two enzymes adsorbed on topologically distinct electrode materials. Escherichia coli NrfA, a nitrite reductase, was adsorbed on mesoporous, nanocrystalline SnO2 electrodes. CymA from Shewanella oneidensis MR-1 reduces menaquinone-7 within 200 nm sized liposomes and this reaction was studied with the enzyme adsorbed on SAM modified ultra-flat gold electrodes. PMID:24634538

McMillan, Duncan G. G.; Marritt, Sophie J.; Kemp, Gemma L.; Gordon-Brown, Piers; Butt, Julea N.; Jeuken, Lars J. C.

2014-01-01

321

Activity regulation of adenosine deaminases acting on RNA (ADARs).  

PubMed

Adenosine deaminases acting on RNA (ADARs) are the enzymes that are responsible for the A to I RNA editing process in mammals, which is an important mechanism that increases molecular diversity. A to I RNA editing consists of an enzymatic conversion of specific adenosine in pre-mRNA, leading to alteration of the properties of both the RNA itself and the translated protein. Currently, the importance of this phenomenon is increasingly recognized as it affects a diverse set of cellular pathways. ADAR function within the cell, especially in the neurons, is to diversify the features of a limited set of unique transcripts, mostly neurotransmitter receptors; however, a growing set of target is going to be discovered, increasing the importance of the RNA editing event in the proper physiology of the cell. Despite the functional relevance of these enzymes, there is a gap of knowledge in the mechanisms that regulate ADAR activity and consequently about the modulation of RNA editing process. This review summarizes ongoing investigations of ADAR regulation at the transcriptional, post-transcriptional and post-translational level and addresses new hypothetical mechanisms that are capable of modulating ADAR activity, including subcellular localization, dimerization and interaction with trans-acting factors. PMID:22113393

Orlandi, Cesare; Barbon, Alessandro; Barlati, Sergio

2012-02-01

322

Illustrating Enzyme Inhibition Using Gibbs Energy Profiles  

ERIC Educational Resources Information Center

Gibbs energy profiles have great utility as teaching and learning tools because they present students with a visual representation of the energy changes that occur during enzyme catalysis. Unfortunately, most textbooks divorce discussions of traditional kinetic topics, such as enzyme inhibition, from discussions of these same topics in terms of…

Bearne, Stephen L.

2012-01-01

323

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

324

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

325

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

326

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

327

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

328

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

329

Enzymes that catalyse the restructuring of proteins  

Microsoft Academic Search

The large enzyme families of protein disulfide isomerases and peptidyl prolyl cis\\/trans isomerases have been shown to assist polypeptide restructuring. Various folding states of polypeptides may serve as substrates of the catalysed reaction. Our understanding of the cellular function of these enzymes is increasing as a result of the availability of more specific inhibitors, the discovery of natural substrates and

Cordelia Schiene; Gunter Fischer

2000-01-01

330

Enzyme adsorption at solid-liquid interfaces  

Microsoft Academic Search

Enzymes are proteins with the capacity of catalysing various reactions. Nowadays two types of enzymes, proteases and lipases, are available for use in detergent formulations for household and industrial laundry washing. Proteases are capable of catalysing the hydrolysis of proteins while lipases enable the hydrolysis of glycerol esters, the main component in fats and non-mineral oils. In this study, two

S. Duinhoven

1992-01-01

331

Cobalamin- and Corrinoid-Dependent Enzymes  

PubMed Central

This chapter will review the literature on cobalamin- and corrinoid-containing enzymes. These enzymes fall into two broad classes, those using methylcobalamin or related methylcorrinoids as prosthetic groups and catalyzing methyltransfer reactions, and those using adenosylcobalamin as the prosthetic group and catalyzing the generation of substrate radicals that in turn undergo rearrangements and/or eliminations. PMID:20877792

Matthews, Rowena G.

2011-01-01

332

Flexibility and reactivity in promiscuous enzymes.  

PubMed

Best of both worlds: The interplay of active site reactivity and the dynamic character of proteins allows enzymes to be promiscuous and--sometimes--remarkably efficient at the same time. This review analyses the roles structural flexibility and chemical reactivity play in the catalytic mechanism of selected enzymes. PMID:23362046

Gatti-Lafranconi, Pietro; Hollfelder, Florian

2013-02-11

333

Formation of oxylipins by CYP74 enzymes  

Microsoft Academic Search

Lipid peroxidation is common to all biological systems, both appearing in developmentally and environmentally regulated processes. Products are hydroperoxy polyunsaturated fatty acids and metabolites derived there from collectively named oxylipins. They may either originate from chemical oxidation or are synthesized by the action of various enzymes, such as lipoxygenases. Cloning of many lipoxygenases and other key enzymes metabolizing oxylipins revealed

Michael Stumpe; Ivo Feussner

2006-01-01

334

Tryptophan-Catabolizing Enzymes - Party of Three  

PubMed Central

Indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) are tryptophan-degrading enzymes that have independently evolved to catalyze the first step in tryptophan catabolism via the kynurenine pathway (KP). The depletion of tryptophan and formation of KP metabolites modulates the activity of the mammalian immune, reproductive, and central nervous systems. IDO and TDO enzymes can have overlapping or distinct functions depending on their expression patterns. The expression of TDO and IDO enzymes in mammals differs not only by tissue/cellular localization but also by their induction by distinct stimuli. To add to the complexity, these genes also have undergone duplications in some organisms leading to multiple isoforms of IDO or TDO. For example, many vertebrates, including all mammals, have acquired two IDO genes via gene duplication, although the IDO1-like gene has been lost in some lower vertebrate lineages. Gene duplications can allow the homologs to diverge and acquire different properties to the original gene. There is evidence for IDO enzymes having differing enzymatic characteristics, signaling properties, and biological functions. This review analyzes the evolutionary convergence of IDO and TDO enzymes as tryptophan-catabolizing enzymes and the divergent evolution of IDO homologs to generate an enzyme family with diverse characteristics not possessed by TDO enzymes, with an emphasis on the immune system.

Ball, Helen J.; Jusof, Felicita F.; Bakmiwewa, Supun M.; Hunt, Nicholas H.; Yuasa, Hajime J.

2014-01-01

335

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...

336

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.

337

Enzyme Activity of Cenococcum geophilum Isolates on Enzyme-specific Solid Media  

PubMed Central

Enzyme activities of Cenococcum geophilum isolates were examined on enzyme-specific solid media. Deoxyribonuclease, phosphatase, and urease were detected in all isolates, whereas cellulase was not detected in any of the isolates. Variations in enzyme activities of amylase, caseinolysis, gelatinase, lipase, and ribonuclease were observed among isolates. PMID:22783090

Obase, Keisuke; Lee, Sang Yong; Chun, Kun Woo

2011-01-01

338

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

339

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

340

Acting Out; Theoretical and Clinical Aspects.  

ERIC Educational Resources Information Center

The beneficial and harmful effects of acting out are studied in a series of short essays by numerous authors. Included are four articles on the theoretical and dynamic considerations of acting out, along with five clinical manifestations of acting out involving suicide and criminality in adolescents and adults. Special forms of harmful acting out…

Abt, Lawrence Edwin, Ed.; Weissman, Stuart L.

341

Enzymic Conversion of Racemates into Aminoacid Enantiomers  

NASA Astrophysics Data System (ADS)

The present state of the art and prospects for further development in the employment of enzymes for the resolution of aminoacid racemates or the conversion of racemates of a series of chemical compounds into optically pure aminoacids are considered. A comparative survey of studies involving the use of aminoacylases, proteases, hydantoinases, ?-aminocaprolactam hydrolase, and a number of other enzymes for the preparation of L- and D- aminoacids has been carried out. Examples are presented of processes involving the enzymic resolution of racemates on an industrial scale. The kinetic and thermodynamic features of the enzymic reactions employed have been analysed in detail and the limits in the employment of a particular enzyme for the conversion of racemates into optically pure aminoacids are accounted for. The bibliography includes 288 references.

Švedas, V.; Galaev, I. U.

1983-12-01

342

Biotechnological uses of enzymes from psychrophiles  

PubMed Central

Summary The bulk of the Earth's biosphere is cold (e.g. 90% of the ocean's waters are ??5°C), sustaining a broad diversity of microbial life. The permanently cold environments vary from the deep ocean to alpine reaches and to polar regions. Commensurate with the extent and diversity of the ecosystems that harbour psychrophilic life, the functional capacity of the microorganisms that inhabitat the cold biosphere are equally diverse. As a result, indigenous psychrophilic microorganisms provide an enormous natural resource of enzymes that function effectively in the cold, and these cold?adapted enzymes have been targeted for their biotechnological potential. In this review we describe the main properties of enzymes from psychrophiles and describe some of their known biotechnological applications and ways to potentially improve their value for biotechnology. The review also covers the use of metagenomics for enzyme screening, the development of psychrophilic gene expression systems and the use of enzymes for cleaning. PMID:21733127

Cavicchioli, R.; Charlton, T.; Ertan, H.; Omar, S. Mohd; Siddiqui, K. S.; Williams, T. J.

2011-01-01

343

A conserved family of enzymes that phosphorylate inositol hexakisphosphate.  

PubMed

Inositol pyrophosphates are a diverse group of high-energy signaling molecules whose cellular roles remain an active area of study. We report a previously uncharacterized class of inositol pyrophosphate synthase and find it is identical to yeast Vip1 and Asp1 proteins, regulators of actin-related protein-2/3 (ARP 2/3) complexes. Vip1 and Asp1 acted as enzymes that encode inositol hexakisphosphate (IP6) and inositol heptakisphosphate (IP7) kinase activities. Alterations in kinase activity led to defects in cell growth, morphology, and interactions with ARP complex members. The functionality of Asp1 and Vip1 may provide cells with increased signaling capacity through metabolism of IP6. PMID:17412958

Mulugu, Sashidhar; Bai, Wenli; Fridy, Peter C; Bastidas, Robert J; Otto, James C; Dollins, D Eric; Haystead, Timothy A; Ribeiro, Anthony A; York, John D

2007-04-01

344

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.

345

Acting Director appointed for OSTP  

NASA Astrophysics Data System (ADS)

John P. McTague has been designated acting director of the White House Office of Science and Technology Policy (OSTP) and acting science advisor to the President. McTague has served as the deputy director of OSTP under director George A. Keyworth II for the last 2 years. After 4½ years as science advisor, Keyworth left OSTP December 31 to start a consulting firm (Eos, December 10, 1985, p. 1219).A physical chemist by training, McTague was chairman of the National Synchrotron Light Source Department at Brookhaven National Laboratory in Upton, N.Y., from 1982 to late 1983, when he took the post at OSTP. From 1970-1982, he was a professor of chemistry and a member of the Institute of Geophysics and Planetary Physics at the University of California, Los Angeles.

346

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

347

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

348

Long acting methods of contraception.  

PubMed

Long acting methods of contraception have been developed and refined over the last 10 years. From the classical long acting progestogen-only depot preparations we now have a range of delivery systems including both combined and progestogen only injection systems and vaginal rings also containing either progestogen only or oestrogen and progestogen in combination. Subcutaneous implants at present containing only a progestogen, offer a range of durations from 2-5 years. The efficacy of these methods is high, with failure rates as low as 0.1 per 100 woman years. However, with progestogen only systems a significant proportion of women develop unpredictable menstrual bleeding, which with counselling is acceptable. The commonest reason for discontinuation still remains menstrual disorders and recent WHO workshops have investigated the cause of this bleeding and refined the reference periods of analysis. The method of action of progestogen-only systems is primarily cervical mucus blockade and prevention of sperm penetration. However, they also tend to produce a thinned atrophic endometrium. Ovarian effects ranging from complete anovulation to disordered luteal phase, persistent follicles and disorganised hormone production add to the contraceptive effect in more than half of the treatment cycles, but cause some of the menstrual disturbance. All these long acting methods are essential to family planning programmes, offering highly acceptable, and in some cases novel methods with high efficacy. PMID:8324615

Newton, J

1993-01-01

349

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

350

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

PubMed

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

2013-12-24

351

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

352

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

353

Fermentation technology targets the use of microorganisms and/or enzymes for the production of value added  

E-print Network

-energy and pharmaceutical sectors. Microbial cells act as factories to produce high value products such as antimicrobial applications such as waste treatment, production of natural food ingredients, the detection of metabolites fromFermentation technology targets the use of microorganisms and/or enzymes for the production

Auckland, University of

354

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

355

Biochem. J. (1989) 257, 339-345 (Printed in Great Britain) Characteristics necessary for an interconvertible enzyme cascade  

E-print Network

. 1. An allosteric effector G acts on one or both of two modifier enzymes E1 and E2, which catalyse-catalysed reactions, does not necessarily produce a greater degree of sensitivity to an effector than one could expect from direct interaction between effector and target reaction. On the contrary, a cascade in which

356

NADP+ -dependent malic enzyme of Rhizobium meliloti.  

PubMed Central

The bacterium Rhizobium meliloti, which forms N2-fixing root nodules on alfalfa, has two distinct malic enzymes; one is NADP+ dependent, while a second has maximal activity when NAD+ is the coenzyme. The diphosphopyridine nucleotide (NAD+)-dependent malic enzyme (DME) is required for symbiotic N2 fixation, likely as part of a pathway for the conversion of C4-dicarboxylic acids to acetyl coenzyme A in N2-fixing bacteroids. Here, we report the cloning and localization of the tme gene (encoding the triphosphopyridine nucleotide [NADP+]-dependent malic enzyme) to a 3.7-kb region. We constructed strains carrying insertions within the tme gene region and showed that the NADP+ -dependent malic enzyme activity peak was absent when extracts from these strains were eluted from a DEAE-cellulose chromatography column. We found that NADP+ -dependent malic enzyme activity was not required for N2 fixation, as tme mutants induced N2-fixing root nodules on alfalfa. Moreover, the apparent NADP+ -dependent malic enzyme activity detected in wild-type (N2-fixing) bacteroids was only 20% of the level detected in free-living cells. Much of that residual bacteroid activity appeared to be due to utilization of NADP+ by DME. The functions of DME and the NADP+ -dependent malic enzyme are discussed in light of the above results and the growth phenotypes of various tme and dme mutants. PMID:8636022

Driscoll, B T; Finan, T M

1996-01-01

357

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

358

A survey of orphan enzyme activities  

PubMed Central

Background Using computational database searches, we have demonstrated previously that no gene sequences could be found for at least 36% of enzyme activities that have been assigned an Enzyme Commission number. Here we present a follow-up literature-based survey involving a statistically significant sample of such "orphan" activities. The survey was intended to determine whether sequences for these enzyme activities are truly unknown, or whether these sequences are absent from the public sequence databases but can be found in the literature. Results We demonstrate that for ~80% of sampled orphans, the absence of sequence data is bona fide. Our analyses further substantiate the notion that many of these enzyme activities play biologically important roles. Conclusion This survey points toward significant scientific cost of having such a large fraction of characterized enzyme activities disconnected from sequence data. It also suggests that a larger effort, beginning with a comprehensive survey of all putative orphan activities, would resolve nearly 300 artifactual orphans and reconnect a wealth of enzyme research with modern genomics. For these reasons, we propose that a systematic effort to identify the cognate genes of orphan enzymes be undertaken. PMID:17623104

Pouliot, Yannick; Karp, Peter D

2007-01-01

359

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

360

Toward a Systems Biology Perspective on Enzyme Evolution*  

PubMed Central

Large superfamilies of enzymes derived from a common progenitor have emerged by duplication and divergence of genes encoding metabolic enzymes. Division of the functions of early generalist enzymes enhanced catalytic power and control over metabolic fluxes. Later, novel enzymes evolved from inefficient secondary activities in specialized enzymes. Enzymes operate in the context of complex metabolic and regulatory networks. The potential for evolution of a new enzyme depends upon the collection of enzymes in a microbe, the topology of the metabolic network, the environmental conditions, and the net effect of trade-offs between the original and novel activities of the enzyme. PMID:22069330

Copley, Shelley D.

2012-01-01

361

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); Sharon Hammes-Schiffer (Pennsylvania State University;Department of Chemistry)

2006-04-14

362

Immobilized Enzymes and Cells as Practical Catalysts  

NASA Astrophysics Data System (ADS)

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, pharmaceutical, and food industries, in clinical and chemical analyses, and in medicine, as well as probable future trends in enzyme technology are discussed.

Klibanov, Alexander M.

1983-02-01

363

Immobilized enzymes and cells as practical catalysts  

SciTech Connect

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, pharmaceutical, and food industries, in clinical and chemical analyses, and in medicine, as well as probable future trends in enzyme technology are discussed.

Klibanov, A.M.

1983-02-11

364

Rh Antibodies Detectable only by Enzyme Technique  

PubMed Central

The titration of Rh antibodies at intervals during pregnancy by various methods has led to evidence for the existence of an Rh antibody or antibodies detectable by an enzyme (papain) method but not by anti-human-globulin. Adsorption experiments show that this antibody is less readily absorbed by red cells than the other Rh antibodies unless the cells are pretreated with enzyme. This fact may possibly account for the finding of a negative or weakly positive anti-human-globulin test associated with moderate or high titres by enzyme techniques. The relationship of this antibody to the general immunization process in pregnant women is discussed. PMID:13886834

Dodd, Barbara E.; Eeles, Doreen A.

1961-01-01

365

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

366

Influence of pulsed electric field on various enzyme activities  

Microsoft Academic Search

Effects of high-voltage pulsed electric field (PEF) on native or thermal denatured enzyme activities were studied. When PEF was applied to various native enzymes, 105–120% of initial enzyme activities were observed after PEF treatment. It was suggested that an activation of enzyme would be possible by PEF treatment. We attempted a refolding of thermal denatured enzyme by using PEF. When

Takayuki Ohshima; Tsuruki Tamura; Masayuki Sato

2007-01-01

367

DNA-relaxing enzyme from Micrococcus luteus.  

PubMed Central

A DNA-relaxing enzyme which catalyzes the conversion of superhelical DNA to a non-superhelical covalently closed form has been purified from Micrococcus luteus to near homogeneity by two chromatographic steps. The enzyme is a single polypeptide chain. As determined by sodium dodecyl sulfate - polyacrylamide gel electrophoresis and gel filtration on Sephadex G 150, the molecular weight is 115,000. The DNA-relaxing activity determined as a function of enzyme concentration follows a sigmoidal curve. The enzyme requires Mg++ for activity. In the presence of 4.5 mM Mg++ addition of 50-250 mM KCl yields incompletely relaxed DNA molecules (intermediates); intermediates are also observed in the absence of KCl, when the reaction is carried out at 0 degree C or at Mg++ concentrations exceeding 10 mM. Images PMID:202927

Hecht, R; Thielmann, H W

1977-01-01

368

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

369

Ribonucleotide reductases: essential enzymes for bacterial life  

PubMed Central

Ribonucleotide reductase (RNR) is a key enzyme that mediates the synthesis of deoxyribonucleotides, the DNA precursors, for DNA synthesis in every living cell. This enzyme converts ribonucleotides to deoxyribonucleotides, the building blocks for DNA replication, and repair. Clearly, RNR enzymes have contributed to the appearance of genetic material that exists today, being essential for the evolution of all organisms on Earth. The strict control of RNR activity and dNTP pool sizes is important, as pool imbalances increase mutation rates, replication anomalies, and genome instability. Thus, RNR activity should be finely regulated allosterically and at the transcriptional level. In this review we examine the distribution, the evolution, and the genetic regulation of bacterial RNRs. Moreover, this enzyme can be considered an ideal target for anti-proliferative compounds designed to inhibit cell replication in eukaryotic cells (cancer cells), parasites, viruses, and bacteria. PMID:24809024

Torrents, Eduard

2014-01-01

370

Directed Evolution of Cyanide Degrading Enzymes  

E-print Network

. However, application of these enzymes in industry requires improving their characteristics. The goal of this dissertation is to better understand cyanide nitrilases, in particular the cyanide dihydratase from of Bacillus pumilus and Pseudomonas stutzeri...

Abou Nader, Mary 1983-

2012-11-12

371

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

372

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

373

An enzyme immunoassay for plasma betamethasone  

SciTech Connect

A sensitive enzyme immunoassay for plasma betamethasone was developed using betamethasone-3-(O-carboxymethyl)oxime-beta-D-galactosidase conjugate as a labelled antigen and 4-methylumbelliferyl-beta-D-galactoside as a fluorescence substrate. The performances of the enzyme immunoassay were compared with that of a radioimmunoassay using /sup 3/H-betamethasone and the same antiserum. The minimal detectable level for the enzyme immunoassay was 0.15 pg/tube or 0.15 ng/ml of plasma, which was remarkably more sensitive than the radioimmunoassay level of 10 pg/tube or 2 ng/ml of plasma. The specificity was sufficient, in particular, the cross reactivity of cortisol as 0.008%. However, the precision of the enzyme immunoassay was inferior to that of the radioimmunoassay.

Kominami, G.; Yamauchi, A.; Ishihara, S.; Kono, M.

1981-03-01

374

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;); Beth A. D. Nichols (Princeton University;)

1991-01-01

375

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

376

Enzyme release and glycolytic energy production.  

PubMed

In substrate-free anoxia, activities of released cytosolic enzymes (LDH, MDH) correlate inversely with the actual ATP level (for both: r = -0.98). At the same time there is a close correlation between lactate production from glycogen and the ATP content (r = 0.98). With external glucose present enzyme release is greatly delayed, but this could be due to the stimulation of glycolysis as well as to the maintenance of high ATP levels. When glycolysis is blocked by iodoacetate under aerobic conditions, the cells also become depleted of high-energy phosphates. This depletion is delayed in the presence of pyruvate. Cytosolic enzyme release again is correlated with total ATP contents, by the same relation in the presence or absence of pyruvate. Glycolytic energy production is negligible in both cases and does not seem to determine enzyme release directly. PMID:3994635

Piper, H M; Spahr, R; Hütter, J F; Spieckermann, P G

1985-01-01

377

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

378

Biotechnological relevance of starch-degrading enzymes  

SciTech Connect

Traditional enzymes, such as the amylases and the proteases, have been improved, novel applications have been found and new and valuable products have been marketed. The enzymatic hydrolysis of starch is described in some detail. (Refs. 8).

Stewart, G.G.

1987-01-01

379

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.

380

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

381

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

382

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;); Franz X. Schmid (Universität Bayreuth, Laboratorium für Biochemie;)

2004-06-25

383

Antioxidative enzyme activities in human erythrocytes  

Microsoft Academic Search

Reliable and standardized methods are necessary to determine the expression of antioxidative enzymes and their role in maintaining health. In addition, the vari- ability of the enzyme activities within the general pop- ulation caused by age, gender, and life-style factors must be described. This study describes methodological conditions that are suitable for analyzing copper-zinc superoxide dismutase (CuZn-SOD), glutathione peroxi- dase

Helle Raun Andersen; Jesper B. Nielsen; Flemming Nielsen; Philippe Grandjean

384

Stability Improvement of a Liquid Enzyme Product  

Microsoft Academic Search

The shelf-life of a previously developed two-part liquid–liquid enzyme ceruminolytic product was improved maintaining the\\u000a same final reconstituted composition and re-formulating the liquid enzyme portion as a drug granulate by a double wet granulation\\u000a process. The critical steps for the preparation of the granulate were studied (mixing\\/granulating times and drying) determining\\u000a the proteolytic activity, the residual ethanol, and the moisture

Núria Jiménez; Maria Luisa Garcia; Javier Galán; Alberto Vallet; Geoffrey Owen; G. Michael Wall

2009-01-01

385

Tissue enzyme studies in Macaca nemestrina monkeys.  

NASA Technical Reports Server (NTRS)

Total enzyme activities in fresh tissue specimens from major organs of Macaca nemestrina were analyzed for lactic dehydrogenase (LDH), creatine phosphokinase (CPK), and aldolase. The concentration of these enzymes varied among the different tissue with skeletal muscle, heart, and brain having the highest activities. LDH isozymes determinations for the various tissues were also made. The spectrum of LDH isozyme distribution appears to be quite specific and characteristic for at least some of the tissues analyzed.

Hubbard, R. W.; Hoffman, R. A.; Jenkins, D.

1971-01-01

386

Possible pathways for lysosomal enzyme delivery  

PubMed Central

Immunogold double-labeling and ultrathin cryosections were used to compare the subcellular distribution of albumin, mannose 6-phosphate receptor (MPR), galactosyltransferase, and the lysosomal enzymes cathepsin D, beta-hexosaminidase, and alpha-glucosidase in Hep G2 cells. MPR and lysosomal enzymes were found throughout the stack of Golgi cisternae and in a trans-Golgi reticulum (TGR) of smooth-surfaced tubules with coated buds and vesicles. The trans-Golgi orientation of TGR was ascertained by the co-localization with galactosyltransferase. MPR was particularly abundant in TGR and CURL, the compartment of uncoupling receptors and ligands. Both TGR and CURL also contained lysosomal enzymes, but endogenous albumin was detected in TGR only. The coated buds on TGR tubules contained MPR, lysosomal enzymes, as well as albumin. MPR and lysosomal enzymes were also found in coated pits of the plasma membrane. CURL tubules seemed to give rise to smooth vesicles, often of the multivesicular body type. In CURL, the enzymes were found in the lumina of the smooth vesicles while MPR prevailed in the tubules. These observations suggest a role of CURL in transport of lysosomal enzymes to lysosomes. When the cells were treated with the lysosomotropic amine primaquine, binding of anti-MPR to the cells in culture was reduced by half. Immunocytochemistry showed that MPR accumulated in TGR, especially in coated buds. Since these buds contain endogenous albumin and lysosomal enzymes also, these data suggest that coated vesicles originating from TGR provide for a secretory route in Hep G2 cells and that this pathway is followed by the MPR system as well. PMID:2933416

1985-01-01

387

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

388

Lysosomal Enzyme Activities in Experimental Granulomatous Inflammation  

Microsoft Academic Search

Foreign-body (dextran beads) and hypersensitivity (antigen-coupled agarose beads) lung granulomas were induced in BALB\\/c mice by the intratracheal injection of beads. Large granulomas developed, which reached peak intensity within 3 days and declined in size thereafter. Aqueous extracts of both granulomas contained high levels of lysosomal enzymes N-acetyl-?-D-glucosaminidase (NAG) and lysozyme. Lysosomal enzyme activities in the extracts correlated with granuloma

Shuji Kaga; Kazuo Kobayashi; Noriko Yamagata; Hiroko T. Takeuchi; Kazue Yoshida; Tomoko Matsuda; Kazuko Nakatani; Tsuyoshi Kasama; Keita Kasahara; Terumi Takahashi

1991-01-01

389

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

390

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

391

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

392

21 CFR 184.1372 - Insoluble glucose isomerase enzyme preparations.  

...2014-04-01 false Insoluble glucose isomerase enzyme preparations. 184.1372 Section 184...184.1372 Insoluble glucose isomerase enzyme preparations. (a) Insoluble glucose isomerase enzyme preparations are used in the...

2014-04-01

393

21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.  

...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

394

21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 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...

2010-04-01

395

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

396

21 CFR 184.1372 - Insoluble glucose isomerase enzyme preparations.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Insoluble glucose isomerase enzyme preparations. 184.1372 Section 184...184.1372 Insoluble glucose isomerase enzyme preparations. (a) Insoluble glucose isomerase enzyme preparations are used in the...

2012-04-01

397

21 CFR 173.150 - Milk-clotting enzymes, microbial.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Milk-clotting enzymes, microbial. 173.150 Section 173...PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.150 Milk-clotting enzymes, microbial. Milk-clotting...

2011-04-01

398

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

399

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

400

21 CFR 173.150 - Milk-clotting enzymes, microbial.  

...2014-04-01 false Milk-clotting enzymes, microbial. 173.150 Section 173...PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.150 Milk-clotting enzymes, microbial. Milk-clotting...

2014-04-01

401

21 CFR 173.150 - Milk-clotting enzymes, microbial.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Milk-clotting enzymes, microbial. 173.150 Section 173...PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.150 Milk-clotting enzymes, microbial. Milk-clotting...

2012-04-01

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 173.150 - Milk-clotting enzymes, microbial.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 true Milk-clotting enzymes, microbial. 173.150 Section 173...PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.150 Milk-clotting enzymes, microbial. Milk-clotting...

2010-04-01

404

21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 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...

2012-04-01

405

21 CFR 184.1372 - Insoluble glucose isomerase enzyme preparations.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Insoluble glucose isomerase enzyme preparations. 184.1372 Section 184...184.1372 Insoluble glucose isomerase enzyme preparations. (a) Insoluble glucose isomerase enzyme preparations are used in the...

2013-04-01

406

21 CFR 864.7100 - Red blood cell enzyme assay.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Red blood cell enzyme assay. 864.7100 Section 864.7100...Packages § 864.7100 Red blood cell enzyme assay. (a) Identification. Red blood cell enzyme assay is a device used to measure...

2013-04-01

407

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

408

21 CFR 184.1372 - Insoluble glucose isomerase enzyme preparations.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 true Insoluble glucose isomerase enzyme preparations. 184.1372 Section 184...184.1372 Insoluble glucose isomerase enzyme preparations. (a) Insoluble glucose isomerase enzyme preparations are used in the...

2010-04-01

409

21 CFR 184.1372 - Insoluble glucose isomerase enzyme preparations.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Insoluble glucose isomerase enzyme preparations. 184.1372 Section 184...184.1372 Insoluble glucose isomerase enzyme preparations. (a) Insoluble glucose isomerase enzyme preparations are used in the...

2011-04-01

410

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

411

21 CFR 862.2500 - Enzyme analyzer for clinical use.  

...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

412

21 CFR 173.150 - Milk-clotting enzymes, microbial.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Milk-clotting enzymes, microbial. 173.150 Section 173...PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.150 Milk-clotting enzymes, microbial. Milk-clotting...

2013-04-01

413

21 CFR 184.1287 - Enzyme-modified fats.  

Code of Federal Regulations, 2012 CFR

...recognized as safe (GRAS). Enzyme-modified milk powder may be prepared with GRAS enzymes from reconstituted milk powder...lipolysis is maintained at a temperature that is optimal for the action of the enzyme until appropriate acid...

2012-04-01

414

21 CFR 184.1287 - Enzyme-modified fats.  

Code of Federal Regulations, 2013 CFR

...recognized as safe (GRAS). Enzyme-modified milk powder may be prepared with GRAS enzymes from reconstituted milk powder...lipolysis is maintained at a temperature that is optimal for the action of the enzyme until appropriate acid...

2013-04-01

415

21 CFR 184.1287 - Enzyme-modified fats.  

...recognized as safe (GRAS). Enzyme-modified milk powder may be prepared with GRAS enzymes from reconstituted milk powder...lipolysis is maintained at a temperature that is optimal for the action of the enzyme until appropriate acid...

2014-04-01

416

Studies of Enzymes in Mitochondrial DNA Precursor Synthesis  

E-print Network

Studies of Enzymes in Mitochondrial DNA Precursor Synthesis Regulatory Mechanisms for Human;Studies of Enzymes in Mitochondrial DNA Precursor Synthesis - Regulatory Mechanisms for Human Thymidine Kinase 2 and Deoxyguanosine Kinase Abstract As important enzymes in mitochondrial nucleotide salvage

417

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

418

Bleaching with lignin-oxidizing enzymes.  

PubMed

General concern about the environmental impact of chlorine bleaching effluents has led to a trend towards elementary chlorine-free or totally chlorine free bleaching methods. Considerable interest has been focused on the use of biotechnology in pulp bleaching, as large number of microbes and the enzymes produced by them are known to be capable of preferential degradation of native lignin and complete degradation of wood. Enzymes of the hemicellulolytic type, particularly xylan-attacking enzymes xylanases are now used commercially in the mills for pulp treatment and subsequent incorporation into bleach sequences. Certain white-rot fungi can delignify Kraft pulps increasing their brightness and their responsiveness to brightening with chemicals. The fungal treatments are too slow but the enzymes produced from the fungi can also delignify pulps and these enzymatic processes are likely to be easier to optimize and apply than the fungal treatments. This article presents an overview of the developments in the application of lignin-oxidizing enzymes in bleaching of chemical pulps. The present knowledge of the mechanisms on the action of enzymes as well as the practical results and advantages obtained on the laboratory and industrial scale are discussed. PMID:17045199

Bajpai, Pratima; Anand, Aradhna; Bajpai, Pramod K

2006-01-01

419

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

420

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

421

Uproar over Milk Substitutes Act.  

PubMed

Health policy activists lobbied 7 years for the Infant Milk Substitutes, Feeding Bottles and Infant Food Bill. Proponents of the bill say that it basically curtails unethical marketing practices, not the sales of baby foods, and argue that it was conceived to reduce the trend of mothers over-diluting commercial milk in order to reduce household expenses as well as stem the potential erosion of knowledge on locally available weaning foods. Even though the bill will become an Act only after its rules and regulations have been finalized, the government has already banned baby food advertisements on television and in other electronic media under its control. Women's groups now argue that the bill tends to focus almost exclusively upon the welfare of children and compromises the position of women who can not lactate adequately. Moreover, they hold that the bill may be used to compel wives to stay out of the formal workforce so that they may feed their babies. The intention of the bill may be meaningless without complementary legislation addressing the problems of working mothers. Specifically, amendments to the Maternity Benefits Act of 1961 would extend maternity leave to 4 months after delivery and lengthen the duration of nursing breaks. It is, however, feared that these changes may reduce employment prospects for women. PMID:12179211

1993-11-15

422

University of Birmingham Equality Act 2010  

E-print Network

unlawful discrimination, harassment and victimisation and other conduct prohibited by the Equality Act 2010University of Birmingham Equality Act 2010 Publication of Equality Information Contents 1 information - Introduction - Age - Disability - Gender Identity - Pregnancy and Maternity - Race - Religion

Heinke, Dietmar

423

45 CFR 670.4 - Prohibited acts.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Prohibited acts. 670.4 Section 670.4 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL...CONSERVATION OF ANTARCTIC ANIMALS AND PLANTS Prohibited Acts, Exceptions §...

2012-10-01

424

45 CFR 670.4 - Prohibited acts.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Prohibited acts. 670.4 Section 670.4 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL...CONSERVATION OF ANTARCTIC ANIMALS AND PLANTS Prohibited Acts, Exceptions §...

2010-10-01

425

45 CFR 670.4 - Prohibited acts.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Prohibited acts. 670.4 Section 670.4 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL...CONSERVATION OF ANTARCTIC ANIMALS AND PLANTS Prohibited Acts, Exceptions §...

2011-10-01

426

45 CFR 670.4 - Prohibited acts.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Prohibited acts. 670.4 Section 670.4 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL...CONSERVATION OF ANTARCTIC ANIMALS AND PLANTS Prohibited Acts, Exceptions §...

2013-10-01

427

10 CFR 490.603 - Prohibited acts.  

Code of Federal Regulations, 2010 CFR

...false Prohibited acts. 490.603 Section 490.603 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Investigations and Enforcement § 490.603 Prohibited acts. It is unlawful...

2010-01-01

428

75 FR 39053 - Sunshine Act Meetings  

Federal Register 2010, 2011, 2012, 2013

...NATIONAL LABOR RELATIONS BOARD Sunshine Act Meetings Time and Dates: All meetings...proceedings under section 8, 9, or 10 of the [National Labor Relations] Act, or any court proceedings collateral or ancillary...

2010-07-07

429

75 FR 54916 - Sunshine Act Meetings  

Federal Register 2010, 2011, 2012, 2013

...NATIONAL LABOR RELATIONS BOARD Sunshine Act Meetings Time and Dates: All meetings...proceedings under section 8, 9, or 10 of the [National Labor Relations] Act, or any court proceedings collateral or ancillary...

2010-09-09

430

77 FR 60146 - Sunshine Act Meetings  

Federal Register 2010, 2011, 2012, 2013

...NATIONAL LABOR RELATIONS BOARD Sunshine Act Meetings TIME AND DATES: All meetings...proceedings under section 8, 9, or 10 of the [National Labor Relations] Act, or any court proceedings collateral or ancillary...

2012-10-02

431

7 CFR 1209.1 - Act.  

Code of Federal Regulations, 2012 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE MUSHROOM PROMOTION, RESEARCH, AND CONSUMER INFORMATION ORDER Mushroom Promotion, Research, and Consumer Information... § 1209.1 Act. Act means the Mushroom Promotion, Research, and Consumer...

2012-01-01

432

7 CFR 1209.1 - Act.  

...COMMODITIES), DEPARTMENT OF AGRICULTURE MUSHROOM PROMOTION, RESEARCH, AND CONSUMER INFORMATION ORDER Mushroom Promotion, Research, and Consumer Information... § 1209.1 Act. Act means the Mushroom Promotion, Research, and Consumer...

2014-01-01

433

7 CFR 1209.1 - Act.  

Code of Federal Regulations, 2013 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE MUSHROOM PROMOTION, RESEARCH, AND CONSUMER INFORMATION ORDER Mushroom Promotion, Research, and Consumer Information... § 1209.1 Act. Act means the Mushroom Promotion, Research, and Consumer...

2013-01-01

434

7 CFR 1209.1 - Act.  

Code of Federal Regulations, 2010 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE MUSHROOM PROMOTION, RESEARCH, AND CONSUMER INFORMATION ORDER Mushroom Promotion, Research, and Consumer Information... § 1209.1 Act. Act means the Mushroom Promotion, Research, and Consumer...

2010-01-01

435

7 CFR 1209.1 - Act.  

Code of Federal Regulations, 2011 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE MUSHROOM PROMOTION, RESEARCH, AND CONSUMER INFORMATION ORDER Mushroom Promotion, Research, and Consumer Information... § 1209.1 Act. Act means the Mushroom Promotion, Research, and Consumer...

2011-01-01

436

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.

437

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) ... let insurance plans give doctors incentives to discourage women from having breast reconstruction after mastectomy? No. The ...

438

47 CFR 32.4 - Communications Act.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Communications Act. 32.4 Section 32.4 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON...COMPANIES Preface § 32.4 Communications Act. Attention is...

2011-10-01

439

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

440

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.

441

7 CFR 930.1 - Act.  

...VEGETABLES, NUTS), DEPARTMENT 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...

2014-01-01

442

77 FR 59548 - Privacy Act; Implementation  

Federal Register 2010, 2011, 2012, 2013

...correction to the amendment of its Privacy Act regulations due to inadvertently...INFORMATION CONTACT: Brian Anderson, Privacy Act Officer, Department of the Treasury, at 202-622-0755, or by email at Privacy@Treasury.gov....

2012-09-28

443

Transforming Growth Factor ?/Activin Signaling Functions as a Sugar-Sensing Feedback Loop to Regulate Digestive Enzyme Expression.  

PubMed

Organisms need to assess their nutritional state and adapt their digestive capacity to the demands for various nutrients. Modulation of digestive enzyme production represents a rational step to regulate nutriment uptake. However, the role of digestion in nutrient homeostasis has been largely neglected. In this study, we analyzed the mechanism underlying glucose repression of digestive enzymes in the adult Drosophila midgut. We demonstrate that glucose represses the expression of many carbohydrases and lipases. Our data reveal that the consumption of nutritious sugars stimulates the secretion of the transforming growth factor ? (TGF-?) ligand, Dawdle, from the fat body. Dawdle then acts via circulation to activate TGF-?/Activin signaling in the midgut, culminating in the repression of digestive enzymes that are highly expressed during starvation. Thus, our study not only identifies a mechanism that couples sugar sensing with digestive enzyme expression but points to an important role of TGF-?/Activin signaling in sugar metabolism. PMID:25284780

Chng, Wen-Bin Alfred; Sleiman, Maroun S Bou; Schüpfer, Fanny; Lemaitre, Bruno

2014-10-01

444

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

445

Heterologous Expression of a Bioactive ?-Hexosyltransferase, an Enzyme Producer of Prebiotics, from Sporobolomyces singularis  

PubMed Central

Galacto-oligosaccharides (GOS) are indigestible dietary fibers that are able to reach the lower gastrointestinal tract to be selectively fermented by health-promoting bacteria. In this report, we describe the heterologous expression of an optimized synthetically produced version of the ?-hexosyltransferase gene (Bht) from Sporobolomyces singularis. The Bht gene encodes a glycosyl hydrolase (EC 3.2.1.21) that acts as galactosyltransferase, able to catalyze a one-step conversion of lactose to GOS. Expression of the enzyme in Escherichia coli yielded an inactive insoluble protein, while the methylotrophic yeast Pichia pastoris GS115 produced a bioactive ?-hexosyltransferase (rBHT). The enzyme exhibited faster kinetics at pHs between 3.5 and 6 and at temperatures between 40 and 50°C. Enzyme stability improved at temperatures lower than 40°C, and glucose was found to be a competitive inhibitor of enzymatic activity. P. pastoris secreted a fraction of the bioactive rBHT into the fermentation broth, while the majority of the enzyme remained associated with the outer membrane. Both the secreted and the membrane-associated forms were able to efficiently convert lactose to GOS. Additionally, resting cells with membrane-bound enzyme converted 90% of the initial lactose into GOS at 68% yield (g/g) (the maximum theoretical is 75%) with no secondary residual (glucose or galactose) products. This is the first report of a bioactive BHT from S. singularis that has been heterologously expressed. PMID:23241974

Dagher, Suzanne F.; Azcarate-Peril, M. Andrea

2013-01-01

446

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

447

Gender Stereotypes Associated with Altruistic Acts  

Microsoft Academic Search

Possible gender stereotypes associated with altruistic acts presented in two types of vignettes were investigated. A sample of 72 General Psychology students were recruited to participate. The researchers had three main hypotheses: Females would more likely be perceived as the performers of an altruistic act, females would more likely be perceived as the receivers of an altruistic act, and the

Lacey D. Seefeldt

448

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

449

American Recovery and Reinvestment Act of 2009  

E-print Network

American Recovery and Reinvestment Act of 2009 Anne Allain Brianna Lysiak Rebecca Bickford Sotheavy Khon #12;American Recovery and Reinvestment Act · On February 17, 2009, President Obama signed the act, and as intended, able to stimulate the job market in Belchertown. This project has always been a priority

Nagurney, Anna

450

ACT National Curriculum Survey[R], 2009  

ERIC Educational Resources Information Center

The ACT National Curriculum Survey is a one-of-a-kind nationwide survey of educational practices and expectations conducted by ACT every 3 to 5 years. ACT surveys thousands of middle school/junior high school, secondary, and postsecondary teachers in English/writing, reading (including English language arts and social studies teachers),…

ACT, Inc., 2009

2009-01-01

451

The ACT User Handbook, 2008-2009  

ERIC Educational Resources Information Center

This handbook is intended to help high school and college counselors effectively use and interpret ACT results. It contains four main sections: Section 1, "Components of the ACT," which contains general information about the ACT tests, probably will be of interest both to high school counselors and to college advisors and other staff. In Section…

ACT, Inc., 2008

2008-01-01

452

The act frequency approach to personality  

Microsoft Academic Search

Personality dispositions are viewed as summaries of act frequencies that, in themselves, possess no explanatory status. As sociocultural emergents, dispositions function as natural cognitive categories with acts as members. Category boundaries are fuzzy, and acts within each category differ in their prototypicality of membership. This formulation is illustrated by a series of studies involving undergraduate raters, which focused on indices

David M. Buss; Kenneth H. Craik

1983-01-01

453

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; Stahlberg, Jerry; Stals, Ingeborg; Tan, Zhongping; Beckham, Gregg T.

2013-01-01

454

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.; Noel, Gaetane; Stroobant, Vincent; Vertommen, Didier; Vincent, Marie-Francoise; Bommer, Guido T.; Veiga-da-Cunha, Maria; Van Schaftingen, Emile

2011-01-01

455

[Enzyme replacement therapies for lysosomal storage disorders.].  

PubMed

The lysosome was discovered in 1955 by Christian de Duve. The first demonstration by Hers of a link between an enzyme deficiency and a storage disorder (Pompe disease) paved the way for seminal discoveries culminating in the successful treatment of Gaucher disease with beta-glucosidase. Today, enzyme replacement therapy is a reality for Fabry disease, mucopolysaccharidosis type I (MPS I) and mucopolysaccharidosis type VI (MPS VI). In patients with MPS I, laronidase (recombinant human alpha-L-iduronidase) significantly improves respiratory function and physical capacities, reduces hepatomegaly and glycosaminoglycan storage, and has a favorable safety profile. Following positive results from phase I and phase II studies, a randomized, double-blind, multicentre phase III trial of galsulfase (recombinant human arylsulfatase B) was conducted in patients affected with MPS VI. Data from this study confirmed the safety and efficacy of galsulfase which significantly improved the 12-minutes walk test and reduced urinary dermatan sulftate. Recombinant human alpha-glucosidase (rhGAA) is currently in clinical trials for therapy of Pompe disease. Clinical data show that the enzyme efficiently clears glycogen from cardiac muscle and type I skeletal muscle fibers, but not type II fibers. Clinical trials with recombinant human enzymes are ongoing in MPS II and about to begin in Niemann-Pick B disease. Significant challenges remain for enzyme replacement therapies, particularly the treatment of central nervous system disease. Alternative strategies, such as substrate deprivation and enzyme enhancement therapy which employs small molecules as "pharmacological chaperones" to rescue misfolded and/or unstable mutant enzymes that have residual function, are currently being investigated. double dagger. PMID:16324679

Germain, Dominique P

2005-12-01

456

National Environmental Policy Act handbook  

SciTech Connect

The Handbook describes Bureau of Reclamation (Reclamation) policy and procedures for implementing the National Environmental Policy Act of 1969 (NEPA) (42 U.S.C. 4321, et seq.), the Council on Environmental Quality's (CEQ) Regulations for Implementing the Procedural Provisions of NEPA (40 CFR (Code of Federal Regulations) Parts 1500-1508) and the Department of the Interior (Department) Manual 516 DM 1-7. The Handbook draws these legal requirements together and explains how to apply them to Reclamation program areas. It also presents and summarizes other related environmental laws and executive orders which must be addressed during NEPA compliance. It should be used in conjunction with other legal documents and Reclamation Instructions (RI).

Not Available

1990-10-01

457

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

458

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

459

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

460

Probing enzyme promiscuity of SGNH hydrolases.  

PubMed

Several hydrolases of the SGNH superfamily, including the lipase SrLip from Streptomyces rimosus (Q93MW7), the acyl-CoA thioesterase I TesA from Pseudomonas aeruginosa (Q9HZY8) and the two lipolytic enzymes EstA (from P. aeruginosa, O33407) and EstP (from Pseudomonas putida, Q88QS0), were examined for promiscuity. These enzymes were tested against four chemically different classes of a total of 34 substrates known to be hydrolysed by esterases, thioesterases, lipases, phospholipases, Tweenases and proteases. Furthermore, they were also analysed with respect to their amino acid sequences and structural homology, and their phylogenetic relationship was determined. The Pseudomonas esterases EstA and EstP each have an N-terminal domain with catalytic activity together with a C-terminal autotransporter domain, and so the hybrid enzymes EstA(N)-EstP(C) and EstP(N)-EstA(C) were constructed by swapping the corresponding N- and C-terminal domains, and their hydrolytic activities were compared. Interestingly, substrate specificity and kinetic measurements indicated a significant influence of the autotransporter domains on the catalytic activities of these enzymes in solution. TesA, EstA and EstP were shown to function as esterases with different affinities and catalytic efficacies towards p-nitrophenyl butyrate. Of all the enzymes tested, only SrLip revealed lipase, phospholipase, esterase, thioesterase and Tweenase activities. PMID:20931591

Leš?i? Ašler, Ivana; Ivi?, Nives; Kova?i?, Filip; Schell, Sabrina; Knorr, Janina; Krauss, Ulrich; Wilhelm, Susanne; Koji?-Prodi?, Biserka; Jaeger, Karl-Erich

2010-10-18

461

Sensitive radioenzymatic assay for epinephrine forming enzymes  

SciTech Connect

Epinephrine (E) is formed in the adrenal medulla by phenylethanolamine-N-methyltransferase (PNMT), and in other tissues. Enzymes other than PNMT may be able to synthesize E, but this has been difficult to investigate because most assays do not have E as their final product. This assay produces /sup 3/H-E from norepinephrine (NE) and /sup 3/H-S-adenosylmethionine. The /sup 3/H-E is isolated on alumina, /sup 3/H-S-adenosylmethionine is precipitated and the /sup 3/H-E is suspended in diethylhexyl phosphoric acid in toluene for scintillation counting. The assay is sensitive and linear over a wide range. E was formed by most tissues tested. Brain and adrenal contained an enzyme specific for NE, but cardiac ventricle contained an enzyme that methylated both NE and dopamine. Denervated tissues in adrenal medullectomized rats contained very little NE, but still had E and E forming enzyme present. This assay detects a non-neuronal E forming enzyme with activity in vitro and in vivo.

Ziegler, M.G.; Kennedy, B.; Elayan, H.

1988-01-01

462

Purification of Limulus polyphemus proclotting enzyme.  

PubMed

Horseshoe crabs (Limulus polyphemus and Tachypleus tridentatus) possess a proteolytic blood coagulation system within their amebocytes that, after release and endotoxin activation, generates a polymerized insoluble coagulin clot. Clotting enzyme from horseshoe crab amebocyte lysate is the protease that activates the clottable protein (coagulogen) which then forms the coagulin clot. Comparison of the previously published descriptions of this enzyme has revealed significantly discordant biochemical characteristics. We purified a 60-kDa proclotting enzyme from L. polyphemus amebocyte lysate to a single band on polyacrylamide gel electrophoresis. After electrophoresis, evaluation of enzymatic activity of this protein within gels demonstrated that the band of purified protein corresponded to enzymatic activity, as detected by amidolytic activity for chromogenic substrates and by gelation of coagulogen applied to the gel. The enzymatic activity was inhibited by serine protease inhibitors. The purified proclotting enzyme had a molecular weight and amino acid composition different from the previously published characterizations of proclotting enzymes from both L. polyphemus and T. tridentatus. PMID:1429741

Roth, R I; Levin, J

1992-11-25

463

Type I restriction enzymes and their relatives.  

PubMed

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

464

A multi-enzyme model for pyrosequencing  

PubMed Central

Pyrosequencing is a DNA sequencing technique based on sequencing-by-synthesis enabling rapid real-time sequence determination. This technique employs four enzymatic reactions in a single tube to monitor DNA synthesis. Nucleotides are added iteratively to the reaction and in case of incorporation, pyrophosphate (PPi) is released. PPi triggers a series of reactions resulting in production of light, which is proportional to the amount of DNA and number of incorporated nucleotides. Generated light is detected and recorded by a detector system in the form of a peak signal, which reflects the activity of all four enzymes in the reaction. We have developed simulations to model the kinetics of the enzymes. These simulations provide a full model for the Pyrosequencing four-enzyme system, based on which the peak height and shape can be predicted depending on the concentrations of enzymes and substrates. Simulation results are shown to be compatible with experimental data. Based on these simulations, the rate-limiting steps in the chain can be determined, and KM and kcat of all four enzymes in Pyrosequencing can be calculated. PMID:15576673

Agah, Ali; Aghajan, Mariam; Mashayekhi, Foad; Amini, Sasan; Davis, Ronald W.; Plummer, James D.; Ronaghi, Mostafa; Griffin, Peter B.

2004-01-01

465

Redesigning allosteric activation in an enzyme  

PubMed Central

Enzyme activation by monovalent cations is widely documented in plants and the animal world. In type II enzymes, activation entails two steps: binding of the monovalent cation to its allosteric site and transduction of this event into enhanced catalytic activity. The effect has exquisite specificity for either Na+ or K+, the most abundant cations present in physiological environments. Enzymes requiring K+ such as kinases and molecular chaperones are not activated as well or at all by the larger cation Cs+ or the smaller cations Na+ and Li+. Enzymes requiring Na+ such as ?-galactosidase and clotting proteases are not activated as well by Li+, or the larger cations K+, Rb+, and Cs+. Efforts to switch specificity between Na+ and K+ in this large class of enzymes and completely redesign the mechanism of allosteric transduction leading to enhanced catalytic activity have so far been unsuccessful. Here we show how mutagenesis of two loops defining the Na+ binding site of thrombin, a Na+-activated clotting protease, generates a construct that is most active in the presence of K+ toward synthetic and physiological substrates. The effect is the result of a higher binding affinity and more efficient allosteric transduction of binding into enhanced catalytic activity for K+ compared to Na+, which represents a complete reversal of the properties of wild type. In addition, the construct features altered specificity toward physiological substrates resulting in a significant anticoagulant profile. The findings are relevant to all Na+-activated proteases involved in blood coagulation and the complement system. PMID:21368156

Rana, Sadhna; Pozzi, Nicola; Pelc, Leslie A.; Di Cera, Enrico

2011-01-01

466

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

Code of Federal Regulations, 2011 CFR

...Banking 6 2011-01-01 2011-01-01 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....

2011-01-01

467

Enzyme-Labeling of Antibodies and Their Fragments for Enzyme Immunoassay and Immunohistochemical Staining  

Microsoft Academic Search

The use of an enzyme as a label has a number of advantages over the use of other labels in both immunohistochemistry and immunoassay. Immunofluorescence techniques are not suitable for ultrastructural research on cells, and ferritin-labeled antibodies allow only electronmicroscopic studies. By contrast, enzyme-labeled antibodies permit localization of cellular antigens in relation to tissue structures under light microscope and also

Eiji Ishikawa; Masayoshi Imagawa; Seiichi Hashida; Shinji Yoshitake; Yoshitaka Hamaguchi; Tetsuo Ueno

1983-01-01

468

Enzyme activity maintenance in packed-bed reactors via continuous enzyme addition  

Microsoft Academic Search

An operational scheme for using immobilized enzymes in packed-bed reactors that permits operation at a constant throughput rate and constant product quality is described. The scheme uses columns operated in series with continuous enzyme volume in the column system. Operation of columns in series is compared to operation where the flow rate is decreased to compensate for a loss of

F. H. Verhoff; S. T. Schlager

1981-01-01

469

NonAlignment Features Based Enzyme\\/Non-Enzyme Classification Using an Ensemble Method  

Microsoft Academic Search

As a growing number of protein structures are resolved without known functions, using computational methods to help predict protein functions from the structures becomes more and more important. Some computational methods predict protein functions by aligning to homologous proteins with known functions, but they fail to work if such homology cannot be identified. In this paper we classify enzymes\\/non-enzymes using

Nicholas J. Davidson; Xueyi Wang

2010-01-01

470

Oral enzyme therapy for celiac sprue  

PubMed Central

Celiac sprue is an inflammatory disease of the small intestine caused by dietary gluten and treated by adherence to a lifelong gluten-free diet. The recent identification of immunodominant gluten peptides, the discovery of their cogent properties, and the elucidation of the mechanisms by which they engender immunopathology in genetically-susceptible individuals have advanced our understanding of the molecular pathogenesis of this complex disease, enabling the rational design of new therapeutic strategies. The most clinically advanced of these is oral enzyme therapy, in which enzymes capable of proteolyzing gluten (i.e. glutenases) are delivered to the alimentary tract of a celiac sprue patient to detoxify ingested gluten in situ. In this chapter, we discuss the key challenges for discovery and preclinical development of oral enzyme therapies for celiac sprue. Methods for lead identification, assay development, gram-scale production and formulation, and lead optimization for next-generation proteases are described and critically assessed. PMID:22208988

Bethune, Michael T; Khosla, Chaitan

2012-01-01

471

Enzyme activity in dialkyl phosphate ionic liquids  

SciTech Connect

The activity of four metagenomic enzymes and an enzyme cloned from the straw mushroom, Volvariellavolvacea were studied in the following ionic liquids, 1,3-dimethylimidazolium dimethyl phosphate, [mmim][dmp], 1-ethyl-3-methylimidazolium dimethyl phosphate, [emim][dmp], 1-ethyl-3-methylimidazolium diethyl phosphate, [emim][dep] and 1-ethyl-3-methylimidazolium acetate, [emim][OAc]. Activity was determined by analyzing the hydrolysis of para-nitrobenzene carbohydrate derivatives. In general, the enzymes were most active in the dimethyl phosphate ionic liquids, followed by acetate. Generally speaking, activity decreased sharply for concentrations of [emim][dep] above 10% v/v, while the other ionic liquids showed less impact on activity up to 20% v/v.

Thomas, M.F.; Dunn, J.; Li, L.-L.; Handley-Pendleton, J. M.; van der lelie, D.; Wishart, J. F.

2011-12-01

472

Contributions of Human Enzymes in Carcinogen Metabolism  

PubMed Central

Considerable support exists for roles of metabolism in modulating the carcinogenic properties of chemicals. In particular, many of these compounds are procarcinogens that require activation to electrophilic forms to exert genotoxic effects. We systematically analyzed the existing literature on metabolism of carcinogens by human enzymes, which has been developed largely in the past 25 years. The metabolism and especially bioactivation of carcinogens are dominated by cytochrome P450 enzymes (66% of bioactivations). Within this group, six P450s—1A1, 1A2, 1B1, 2A6, 2E1, and 3A4—accounted for 77% of the P450 activation reactions. The roles of these P450s can be compared with those estimated for drug metabolism and should be considered in issues involving enzyme induction, chemoprevention, molecular epidemiology, inter-individual variations, and risk assessment. PMID:22531028

Rendic, Slobodan; Guengerich, F. Peter

2012-01-01

473

A bioinformatics view of zinc enzymes.  

PubMed

Thanks to the contributions of scientists like Bert Vallee, zinc enzymology is an area of research with a rich history and a strong basis of biochemical and biophysical knowledge. In recent years, the dramatic development of the genomic and post-genomic research has provided this as well as all other fields of life sciences with a massive body of new data, including, but not limited to, protein sequence and structural data. By integrating these new data with the wealth of information available in the literature, it is possible to achieve an unprecedented overview of the properties and functions of zinc enzymes in the context of biological systems. To this aim, the role of bioinformatics is essential. In this work, we use bioinformatics tools and databases that we have developed for the study of metalloproteins to gain insights into the functions of zinc in zinc enzymes, its coordination properties, and the usage of zinc enzymes in living organisms. PMID:22209023

Andreini, Claudia; Bertini, Ivano

2012-06-01

474

Enzyme Nanoparticles-Based Electronic Biosensor  

SciTech Connect

A novel method for fabricating electronic biosensors based on coupling enzyme nanoparticles and self assembly technology is illustrated. Redox horseradish peroxidase nanoparticles were prepared by desolvation with ethanol and subsequent crosslinking with glutaraldehyde. The cross-linked enzyme nanoparticles were functionalized by cysteine to introduce thiol groups on the nanoparticle surface. Immobilized enzyme nanoparticle on the gold electrode by self-assembly kept redox and electrocatalytic activities, and was used to develop reagentless biosensors for H2O2 detection without promoters and mediators. The new approach is simple, low cost and circumvents complications associated with solution systems. It is a universal immobilization method for biosensor, biomedical devices, biofuel cells and enzymatic bioreactors fabrication and expected to open new opportunities for biosensor, clinical diagnostics, and for bioanalysis, in general.

Liu, Guodong; Lin, Yuehe; Ostatna, V.; Wang, Joseph

2005-06-28

475

Ultrasound in Enzyme Activation and Inactivation  

NASA Astrophysics Data System (ADS)

As discussed in previous chapters, most effects due to ultrasound arise from cavitation events, in particular, collapsing cavitation bubbles. These collapsing bubbles generate very high localized temperatures and pressure shockwaves along with micro-streaming that is associated with high shear forces. These effects can be used to accelerate the transport of substrates and reaction products to and from enzymes, and to enhance mass transfer in enzyme reactor systems, and thus improve efficiency. However, the high velocity streaming, together with the formation of hydroxy radicals and heat generation during collapsing of bubbles, may also potentially affect the biocatalyst stability, and this can be a limiting factor in combined ultrasound/enzymatic applications. Typically, enzymes can be readily denatured by slight changes in environmental conditions, including temperature, pressure, shear stress, pH and ionic strength.

Mawson, Raymond; Gamage, Mala; Terefe, Netsanet Shiferaw; Knoerzer, Kai

476

Multicarbohydrase Enzymes for Non-ruminants  

PubMed Central

The first purpose of this review is to outline some of the background information necessary to understand the mechanisms of action of fibre-degrading enzymes in non-ruminants. Secondly, the well-known and understood mechanisms are described, i) eliminating the nutrient encapsulating effect of the cell wall and ii) ameliorating viscosity problems associated with certain Non Starch Polysaccharides, particularly arabinoxylans and ?-glucans. A third, indirect mechanism is then discussed: the activity of such enzymes in producing prebiotic oligosaccharides and promoting beneficial cecal fermentation. The literature contains a wealth of information on various non starch polysaccharide degrading enzyme (NSPase) preparations and this review aims to conclude by discussing this body of work, with reference to the above mechanisms. It is suggested that the way in which multi- versus single-component products are compared is often flawed and that some continuity should be employed in methods and terminology. PMID:25049954

Masey O'Neill, H. V.; Smith, J. A.; Bedford, M. R.

2014-01-01

477

De novo enzyme design using Rosetta3.  

PubMed

The Rosetta de novo enzyme design protocol has been used to design enzyme catalysts for a variety of chemical reactions, and in principle can be applied to any arbitrary chemical reaction of interest. The process has four stages: 1) choice of a catalytic mechanism and corresponding minimal model active site, 2) identification of sites in a set of scaffold proteins where this minimal active site can be realized, 3) optimization of the identities of the surrounding residues for stabilizing interactions with the transition state and primary catalytic residues, and 4) evaluation and ranking the resulting designed sequences. Stages two through four of this process can be carried out with the Rosetta package, while stage one needs to be done externally. Here, we demonstrate how to carry out the Rosetta enzyme design protocol from start to end in detail using for illustration the triosephosphate isomerase reaction. PMID:21603656

Richter, Florian; Leaver-Fay, Andrew; Khare, Sagar D; Bjelic, Sinisa; Baker, David

2011-01-01

478

De Novo Enzyme Design Using Rosetta3  

PubMed Central

The Rosetta de novo enzyme design protocol has been used to design enzyme catalysts for a variety of chemical reactions, and in principle can be applied to any arbitrary chemical reaction of interest, The process has four stages: 1) choice of a catalytic mechanism and corresponding minimal model active site, 2) identification of sites in a set of scaffold proteins where this minimal active site can be realized, 3) optimization of the identities of the surrounding residues for stabilizing interactions with the transition state and primary catalytic residues, and 4) evaluation and ranking the resulting designed sequences. Stages two through four of this process can be carried out with the Rosetta package, while stage one needs to be done externally. Here, we demonstrate how to carry out the Rosetta enzyme design protocol from start to end in detail using for illustration the triosephosphate isomerase reaction. PMID:21603656

Richter, Florian; Leaver-Fay, Andrew; Khare, Sagar D.; Bjelic, Sinisa; Baker, David

2011-01-01

479

Cold adaptation of enzyme reaction rates.  

PubMed

A major issue for organisms living at extreme temperatures is to preserve both stability and activity of their enzymes. Cold-adapted enzymes generally have a reduced thermal stability, to counteract freezing, and show a lower enthalpy and a more negative entropy of activation compared to mesophilic and thermophilic homologues. Such a balance of thermodynamic activation parameters can make the reaction rate decrease more linearly, rather than exponentially, as the temperature is lowered, but the structural basis for rate optimization toward low working temperatures remains unclear. In order to computationally address this problem, it is clear that reaction simulations rather than standard molecular dynamics calculations are needed. We have thus carried out extensive computer simulations of the keto-enol(ate) isomerization steps in differently adapted citrate synthases to explore the structure-function relationships behind catalytic rate adaptation to different temperatures. The calculations reproduce the absolute rates of the psychrophilic and mesophilic enzymes at 300 K, as well as the lower enthalpy and more negative entropy of activation of the cold-adapted enzyme, where the latter simulation result is obtained from high-precision Arrhenius plots. The overall catalytic effect originates from electrostatic stabilization of the transition state and enolate and the reduction of reorganization free energy. The simulations, however, show psychrophilic, mesophilic, and hyperthermophilic citrate synthases to have increasingly stronger electrostatic stabilization of the transition state, while the energetic penalty in terms of internal protein interactions follows the reverse order with the cold-adapted enzyme having the most favorable energy term. The lower activation enthalpy and more negative activation entropy observed for cold-adapted enzymes are found to be associated with a decreased protein stiffness. The origin of this effect is, however, not localized to the active site but to other regions of the protein structure. PMID:18759500

Bjelic, Sinisa; Brandsdal, Bjørn O; Aqvist, Johan

2008-09-23

480

NetLogo Models Library: Enzyme Kinetics  

NSDL National Science Digital Library

Model page from the NetLogo Models Library. The page provides a description and screenshots of a mode of Enzme Kinetics produced using the NetLogo software. The page provides a link to a javascript version of the model that can be run in the browser, as well as a download link for the model file that can be opened, run and edited in NetLogo. This model demonstrates the kinetics of single-substrate enzyme-catalysis. The interactions between enzymes and substrates are often difficult to understand and the model allows users to visualize the complex reaction.

Wilensky, Uri; Stieff, Mike

481

Artificial Enzyme Construction with Temperature Sensitivity  

Microsoft Academic Search

\\u000a Poly (N-isopropylacrylamide) (PNIPAAm) is one of the most popular thermoresponsive polymers, which shows dramatic and reversible\\u000a phase transition behavior in water. Therefore two strategies for the design of temperature-sensitive enzyme model based on\\u000a PNIPAAm derivatives are presented: 1) A temperature-sensitive block copolymer (PAAm-b-PNIPAAm-Te) with a glutathione peroxidase-like\\u000a active site was synthesized via ATRP. 2) An artificial bifunctional enzyme with both

Tingting Lin; Jun Lin; Xin Huang; Junqiu Liu

482

Enzymes in bast fibrous plant processing.  

PubMed

The program COST Action 847 Textile Quality and Biotechnology (2000-2005) has given an excellent chance to review the possibilities of the research, aiming at development of the industrial application of enzymes for bast fibrous plant degumming and primary processing. The recent advancements in enzymatic processing of bast fibrous plants (flax, hemp, jute, ramie and alike plants) and related textiles are given. The performance of enzymes in degumming, modification of bast fibres, roving, yarn, related fabrics as well as enzymatic bonding of lignocellulosic composites is provided. PMID:16791732

Kozlowski, Ryszard; Batog, Jolanta; Konczewicz, Wanda; Mackiewicz-Talarczyk, Maria; Muzyczek, Malgorzata; Sedelnik, Natalia; Tanska, Bogumila

2006-05-01

483

ENZYME LINKED IMMUNOSORBENT ASSAY FOR MILK PROGESTERONE  

Microsoft Academic Search

A direct antigen heterologous enzyme linked immunosorbent assay (ELISA) for milk progesterone has been developed using progesterone-3-O-carboxymethyloxime-bovine serum albumin (P-3-O-CMO-BSA) antiserum and 17-?-hydroxy-progesterone-3-O-carboxymethyloxime-horseradish peroxidase (17-?-OH-P-3-O-CMO-HRP) enzyme conjugate. The data of the present study reveal that the homologous assay, which employed P-3-O-CMO-HRP as the label, showed no displacement. On the contrary, replacement of P-3-O-CMO-HRP with 17-?-OH-P-3-O-CMO-HRP as the label showed significant

Tulsidas G. Shrivastav; Shail K. Chaube; Charu; Kiran Rangari; Kiran P. Kariya; Rita Singh; Anjali Nagendra

2010-01-01

484

Directed Enzyme Evolution and High-Throughput Screening  

E-print Network

3 Directed Enzyme Evolution and High-Throughput Screening Michael J. McLachlan,1 Ryan P. Sullivan2, and Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA 3.1 Introduction Early enzyme of a complex mixture of secreted enzymes produced at low yields. Now, over 90% of industrial enzymes

Zhao, Huimin

485

PURIFICATION AND ISOLATION OF THE PHOSPHOGLYCERATE KINASE ENZYME  

E-print Network

PURIFICATION AND ISOLATION OF THE PHOSPHOGLYCERATE KINASE ENZYME IN RICE PLANTS Cynthia Bach (NADH). The enzyme, phosphoglycerate kinase (PGKase), catalyzes the reaction that results to purify the enzyme from developing rice seeds. Isolation of the enzyme was obtained by obtaining a crude

Collins, Gary S.

486

Stochastic Simulation of Enzyme-Catalyzed Reactions with Disparate Timescales  

E-print Network

Stochastic Simulation of Enzyme-Catalyzed Reactions with Disparate Timescales Debashis Barik-steady-state approximation'' for enzyme-catalyzed reactions provides a useful framework for efficient and accurate stochastic simulations. The method is applied to three examples: a simple enzyme-catalyzed reaction where enzyme

Paul, Mark

487

Nanoparticle cages for enzyme catalysis in organic media.  

PubMed

Encapsulation of enzymes in Pickering emulsions results in a large interfacial area of the enzyme-containing aqueous phase for biocatalysis in organic media. This immobilization technique minimizes enzyme inactivation through stabilizing immiscible liquids by particles, facilitates separation processes, and significantly increases catalytic performance of both stable and vulnerable enzymes. Thus, a broad technical applicability can be envisioned. PMID:22072496

Wu, Changzhu; Bai, Shuo; Ansorge-Schumacher, Marion B; Wang, Dayang

2011-12-15

488

Understanding bistability in complex enzyme-driven reaction networks  

E-print Network

to variations in enzyme transcription activity (or even to enzyme malformation) when, in fact, those changesUnderstanding bistability in complex enzyme-driven reaction networks Gheorghe Craciun* , Yangzhong for enzyme catalysis of a single overall reaction. We present a theorem that distinguishes between those mass

Craciun, Gheorghe

489

Original article Activity of enzymes and fitness variation  

E-print Network

Original article Activity of enzymes and fitness variation M. Miloševi&jadnr; D. Marinkovi that significant correlations exist between enzyme activities and studies fitness components, which might be due of development - enzyme activities - fitness components Résumé — Activité des enzymes et variabilité de la

Boyer, Edmond

490

Enzymic Approach to Eurythermalism of Alvinella pompejana and Its Episymbionts  

Microsoft Academic Search

The equilibrium model, which describes the influence of temperature on enzyme activity, has been estab- lished as a valid and useful tool for characterizing enzyme eurythermalism and thermophily. By introducing Keq, a temperature-dependent equilibrium constant for the interconversion between Eact, the active form of enzyme, and Einact, a reversibly inactive form of enzyme, the equilibrium model currently provides the most

Charles K. Lee; S. Craig Cary; Alison E. Murray; Roy M. Daniel

2008-01-01

491

Original article The effect of feed enzymes on nutrient  

E-print Network

Original article The effect of feed enzymes on nutrient and energy retention in young racing. No difference in body weight was observed between groups. Despite feed restriction, intake was higher for enzyme-sup- plemented diet. When related to feed intake, excreta were lower by 11% for enzyme-supplemented diet. Enzyme

Paris-Sud XI, Université de

492

Food-processing enzymes from recombinant microorganisms—a review  

Microsoft Academic Search

Enzymes are commonly used in food processing and in the production of food ingredients. Enzymes traditionally isolated from culturable microorganisms, plants, and mammalian tissues are often not well-adapted to the conditions used in modern food production methods. The use of recombinant DNA technology has made it possible to manufacture novel enzymes suitable for specific food-processing conditions. Such enzymes may be

Zofia S. Olempska-Beer; Robert I. Merker; Mary D. Ditto; Michael J. DiNovi

2006-01-01

493

Occupational Sensitization to Fungal Enzymes Used in Animal Feed Industry  

Microsoft Academic Search

Background: Industrial enzymes cause the increasing prevalence of occupational hypersensitivity. Our objective was to study workers occupationally exposed to fungal enzymes in 2 animal feed factories to determine if the sensitization originated in the enzymes or was caused by the microorganism used to produce the enzymes. Methods: Eighty-six consenting workers were studied by skin prick tests with extracts from the

María Luisa Caballero; María Gómez; Miguel González-Muñoz; Luis Reinoso; Rosa Rodríguez-Pérez; Enrique Alday; Ignacio Moneo

2007-01-01

494

A first prototype of PyACTS  

SciTech Connect

The ACTS Collection is a set of software tools that help developers or programmers write high performance parallel codes for their scientific applications. PyACTS is a Python-based interface to some of the tools in the ACTS Collection. The main purpose of developing PyACTS is to provide a uniform easy-to-use external interface to existing ACTS tools,and support ACTS users to rapidly prototype their codes with the tools. In particular, for users who are new to ACTS, they will find PyACTS helpful to test and try the functionality available in the collection. Further, this training will allow users to acquire the necessary experience to develop their own applications. In the current development phase of PyACTS, part of the ScaLAPACK subroutines are being made available. This report illustrates how we develop the idea of wrapping the ACTS Collection with a high level scripting language, like Python, and a status of the development of the Python front-end interface and future plans.

Kang, Ning; Drummond, Leroy A.

2003-08-31

495

Is acting on delusions autonomous?  

PubMed Central

In this paper the question of autonomy in delusional disorders is investigated using a phenomenological approach. I refer to the distinction between freedom of intentional action, and freedom of the will, and develop phenomenological descriptions of lived autonomy, taking into account the distinction between a pre-reflective and a reflective type. Drawing on a case report, I deliver finely-grained phenomenological descriptions of lived autonomy and experienced self-determination when acting on delusions. This analysis seeks to demonstrate that a person with delusions can be described as responsible for her behaviour on a ‘framed’ level (level of freedom of intentional action), even though she is not autonomous on a higher (‘framing’) level (level of freedom of the will), if, and only if, the goods of agency for herself and others are respected. In these cases the person with delusions is very nearly comparable to people in love, who are also not free to choose their convictions, and who could also be rightly held responsible for the behaviour flowing from their convictions. PMID:24125114

2013-01-01

496

Fast acting inlet guide vanes  

SciTech Connect

A fast acting inlet guide vane (IGV) system was developed for the model Siemens V94.2 gas turbine (GT). This system enables the GT to perform larger and faster load changes in the case of electrical grid disturbances. Disturbances in electrical grids are caused by an unbalance between actual power generation and power consumption resulting in grid frequency deviations. In order to reduce such deviations, it is desirable for a GT (connected to the grid), to increase/reduce load as fast as required. This task is achieved by the fast responding IGV system: Basically, the occurring grid frequency deviation is monitored by the IGV system. Depending on this deviation, the compressor air mass flow is adapted to the changing fuel mass flow (which is set approximately proportional to the frequency deviation by the GT controller). The fast IGV actuator plays a main role in this dynamic response, allowing the vanes to open/close very fast. Tests performed on Poolbeg site (Ireland) proved safe and rapid load changes with a typical load ramp of 50 MW within 3 sec.

Minne, M.; Kull, R.

1998-07-01

497

Naloxone inhibits superoxide but not enzyme release by human neutrophils  

SciTech Connect

The release of toxic oxygen metabolites and enzymes by phagocytic cells is thought to play a role in the multisystemic tissue injury of sepsis. Naloxone protects septic animals. We have found that at concentrations administered to animals (10/sup -7/ to 10/sup -4/M), naloxone inhibited (p < .001) the release of superoxide (O/sub 2//sup -/) by human neutrophils (HN), stimulated with N-formyl methionyl leucyl phenylalanine (FMLP). Naloxone had no effect on cell viability. Maximum inhibition was 65% of the total O/sub 2//sup -/ released (13.1 nMoles/8 min/320,000 cells). FMLP-stimulated release of beta-glucoronidase or lysozyme was not altered by naloxone. Naloxone had no effect on the binding of /sup 3/H FMLP to HN. Using /sup 3/H naloxone and various concentrations of unlabeled naloxone higher affinity (K/sub D/ = 12nM) and lower affinity (K/sub D/ = 4.7 x 10/sup -5/) binding sites were detected. The K/sub D/ of the low affinity site corresponded to the ED/sub 50/ for naloxone inhibition of O/sub 2//sup -/ (1 x 10/sup -5/M). Binding to this low affinity site was decreased by (+) naloxone, beta-endorphin and N acetyl beta-endorphin, but not by leu-enkephalin, thyrotropin releasing factor, prostaglandin D/sub 2/ or E/sub 2/. Conclusions: (1) naloxone inhibits FMLP-stimulated O/sub 2/ but not enzyme release, (2) this inhibition is not due to alteration of FMLP receptor binding, (3) naloxone may act via a low affinity binding site which is ligand specific, and (4) a higher affinity receptor is present on HN.

Simpkins, C.; Alailima, S.; Tate, E.

1986-03-01

498

Introduction to Enzyme Kinetics: Assay of beta-Galactosidase  

NSDL National Science Digital Library

This tutorial describes a colorometric enzyme assay to determine simple enzyme kinetics. It is designed as an introduction for beginning laboratory students in a biology or biochemistry course, and requires no previous understanding of chemistry. It may be used as an assignment to prepare students for a laboratory exercise in enzyme kinetics Through this tutorial, students will gain an understanding of the procedures for measuring enzyme activity, using the specific example of an assay for the bacterial enzyme, β-galactosidase.

Joanne Kivela Tillotson (State University of New York;Purchase College REV)

2007-07-10

499

78 FR 5784 - Privacy Act of 1974; System of Records  

Federal Register 2010, 2011, 2012, 2013

...Act Program Manager, Corporate Communications...Federal Agency Responsibilities for Maintaining...telephone number, Social Security Numbers...Act Program Manager, Corporate Communications...Act Program Manager, Corporate...

2013-01-28

500

A Qualitative Approach to Enzyme Inhibition  

ERIC Educational Resources Information Center

Most general biochemistry textbooks present enzyme inhibition by showing how the basic Michaelis-Menten parameters K[subscript m] and V[subscript max] are affected mathematically by a particular type of inhibitor. This approach, while mathematically rigorous, does not lend itself to understanding how inhibition patterns are used to determine the…

Waldrop, Grover L.

2009-01-01