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1

Aspergillus niger genome-wide analysis reveals a large number of novel alpha-glucan acting enzymes with unexpected expression profiles  

PubMed Central

The filamentous ascomycete Aspergillus niger is well known for its ability to produce a large variety of enzymes for the degradation of plant polysaccharide material. A major carbon and energy source for this soil fungus is starch, which can be degraded by the concerted action of ?-amylase, glucoamylase and ?-glucosidase enzymes, members of the glycoside hydrolase (GH) families 13, 15 and 31, respectively. In this study we have combined analysis of the genome sequence of A. niger CBS 513.88 with microarray experiments to identify novel enzymes from these families and to predict their physiological functions. We have identified 17 previously unknown family GH13, 15 and 31 enzymes in the A. niger genome, all of which have orthologues in other aspergilli. Only two of the newly identified enzymes, a putative ?-glucosidase (AgdB) and an ?-amylase (AmyC), were predicted to play a role in starch degradation. The expression of the majority of the genes identified was not induced by maltose as carbon source, and not dependent on the presence of AmyR, the transcriptional regulator for starch degrading enzymes. The possible physiological functions of the other predicted family GH13, GH15 and GH31 enzymes, including intracellular enzymes and cell wall associated proteins, in alternative ?-glucan modifying processes are discussed. Electronic supplementary material The online version of this article (doi:10.1007/s00438-008-0332-7) contains supplementary material, which is available to authorized users. PMID:18320228

Yuan, Xiao-Lian; van der Kaaij, Rachel M.; van den Hondel, Cees A. M. J. J.; Punt, Peter J.; van der Maarel, Marc J. E. C.; Dijkhuizen, Lubbert

2008-01-01

2

Structure of a novel highly branched alpha-glucan enzymatically produced from maltodextrin.  

PubMed

The bacterial strain PP710, isolated from soil and identified as Paenibacillus species, produced a low-digestibility alpha-glucan containing a large amylase-resistant portion. This alpha-glucan was obtained in high yields from maltodextrin (dextrose equivalent 3) by using the condensed culture supernatant of the strain as the enzyme preparation. The water-soluble dietary fiber content of the low-digestibility alpha-glucan was 80.2%, and showed resistance to a rat intestinal enzyme preparation. The alpha-glucan was found to be a novel highly branched alpha-glucan by acid hydrolysis, NMR analysis, gel permeation chromatography, methylation analysis, and enzymatic digestion. PMID:19740459

Tsusaki, Keiji; Watanabe, Hikaru; Nishimoto, Tomoyuki; Yamamoto, Takuo; Kubota, Michio; Chaen, Hiroto; Fukuda, Shigeharu

2009-11-01

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

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 ...

5

A Natural Vanishing Act: The Enzyme-Catalyzed Degradation of Carbon Nanomaterials  

PubMed Central

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

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

2012-01-01

6

Extracellular calcium acts as a “third messenger” to regulate enzyme and alkaline secretion  

PubMed Central

It is generally assumed that the functional consequences of stimulation with Ca2+-mobilizing agonists are derived exclusively from the second messenger action of intracellular Ca2+, acting on targets inside the cells. However, during Ca2+ signaling events, Ca2+ moves in and out of the cell, causing changes not only in intracellular Ca2+, but also in local extracellular Ca2+. The fact that numerous cell types possess an extracellular Ca2+ “sensor” raises the question of whether these dynamic changes in external [Ca2+] may serve some sort of messenger function. We found that in intact gastric mucosa, the changes in extracellular [Ca2+] secondary to carbachol-induced increases in intracellular [Ca2+] were sufficient and necessary to elicit alkaline secretion and pepsinogen secretion, independent of intracellular [Ca2+] changes. These findings suggest that extracellular Ca2+ can act as a “third messenger” via Ca2+ sensor(s) to regulate specific subsets of tissue function previously assumed to be under the direct control of intracellular Ca2+. PMID:15240573

Caroppo, Rosa; Gerbino, Andrea; Fistetto, Gregorio; Colella, Matilde; Debellis, Lucantonio; Hofer, Aldebaran M.; Curci, Silvana

2004-01-01

7

Biology of a novel class of potent long-acting angiotensin converting enzyme inhibitors: the acyl lysinamido phosphonates.  

PubMed

The acyl lysinamido phosphonates represent a novel class of angiotensin I converting enzyme (ACE) inhibitors. Representatives of this class produce 50% inhibition of purified rabbit lung ACE at concentrations less than 8 nmol/l. After intravenous and oral administration to normotensive rats the phosphonates inhibited an angiotensin I pressor response by 50% at doses less than or equal to enalapril (oral studies) or its free acid, MK-422 (intravenous studies); however, the duration of effect was much longer after the phosphonates. In conscious cynomolgus monkeys, representatives of the phosphonate class showed greater inhibition of an angiotensin I pressor response and for a much longer period of time than enalapril, fosinopril and lisinopril. Similarly, in sodium-depleted monkeys the blood pressure lowering effects of enalapril, lisinopril and fosinopril were of short duration compared with those of the phosphonates. It is concluded that the acyl lysinamido phosphonates represent a potent and long-acting class of ACE inhibitors in vitro and in vivo. PMID:3241238

DeForrest, J M; Waldron, T L; Scalese, R J; Harvey, C M

1988-12-01

8

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

PubMed

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

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

2014-11-01

9

Undariase, a direct-acting fibrin(ogen)olytic enzyme from Undaria pinnatifida, inhibits thrombosis in vivo and exhibits in vitro thrombolytic properties.  

PubMed

A direct-acting fibrinolytic serine protease named undariase possessing anticoagulant and antiplatelet properties was purified from Undaria pinnatifida. Undariase showed a molecular weight of 50 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and mass spectrometry. It displayed a strong fibrin zymogram lysis band corresponding to the same molecular mass. The N-terminal sequence of undariase, LTATTCEELAAAPTD, does not match with any known fibrinolytic enzyme. The enzyme was stable and active at high temperatures (35-70 °C). The fibrinolytic activity of undariase was strongly inhibited by phenylmethylsulfonyl fluoride (PMSF) and 4-(amidinophenyl) methanesulfonyl fluoride (APMSF). The K m and V max values for substrate S-2251 were determined as 6.15 mM and 90.91 mM/min/ml, respectively. Undariase resulted in clot lysis by directly cleaving ? and ? chains of fibrin. Similarly, it preferentially acted on the A? chain of fibrinogen followed by cleavage of the B? chain. It significantly prolonged the PFA-100 closure times of citrated whole human blood. In addition, undariase delayed the coagulation time and increased activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT). Undariase exerted a significant protective effect against collagen plus epinephrine-induced pulmonary thromboembolism in mice. It prevented carrageenan-induced thrombus formation in the tail of mice. It also resulted in prolongation of APTT ex vivo. In conclusion, these results suggested a therapeutic potential of undariase for thrombosis. PMID:24938821

Choi, Jun-Hui; Sapkota, Kumar; Kim, Myung-Kon; Kim, Seung; Kim, Sung-Jun

2014-08-01

10

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

SciTech Connect

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

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

2008-01-01

11

Glucan synthesis in the genus Lactobacillus: isolation and characterization of glucansucrase genes, enzymes and glucan products from six different strains.  

PubMed

Members of the genera Streptococcus and Leuconostoc synthesize various alpha-glucans (dextran, alternan and mutan). In Lactobacillus, until now, the only glucosyltransferase (GTF) enzyme that has been characterized is gtfA of Lactobacillus reuteri 121, the first GTF enzyme synthesizing a glucan (reuteran) that contains mainly alpha-(1-->4) linkages together with alpha-(1-->6) and alpha-(1-->4,6) linkages. Recently, partial sequences of glucansucrase genes were detected in other members of the genus Lactobacillus. This paper reports, for the first time, isolation and characterization of dextransucrase and mutansucrase genes and enzymes from various Lactobacillus species and the characterization of the glucan products synthesized, which mainly have alpha-(1-->6)- and alpha-(1-->3)-glucosidic linkages. The four GTF enzymes characterized from three different Lb. reuteri strains are highly similar at the amino acid level, and consequently their protein structures are very alike. Interestingly, these four Lb. reuteri GTFs have relatively large N-terminal variable regions, containing RDV repeats, and relatively short putative glucan-binding domains with conserved and less-conserved YG-repeating units. The three other GTF enzymes, isolated from Lactobacillus sakei, Lactobacillus fermentum and Lactobacillus parabuchneri, contain smaller variable regions and larger putative glucan-binding domains compared to the Lb. reuteri GTF enzymes. PMID:15528655

Kralj, S; van Geel-Schutten, G H; Dondorff, M M G; Kirsanovs, S; van der Maarel, M J E C; Dijkhuizen, L

2004-11-01

12

Aminoglycoside-modifying enzyme of an antibiotic-producing bacterium acts as a determinant of antibiotic resistance in Escherichia coli.  

PubMed Central

Bacillus circulans NRRL B-3312, a nonpathogenic bacterium that produces the aminoglycoside antibiotic butirosin, is known to contain an aminoglycoside phosphotransferase that is similar to the neomycin phosphotransferases of clinically isolated antibiotic-resistant bacteria. Purified DNAs from B. circulans and the plasmid ColE1-ApR were digested with EcoRI endonuclease and the resulting fragments covalently joined with polynucleotide ligase. The recombined DNA was used to transform E. coli and ampicillin-neomycin resistant colonies were selected. Analysis of several clones indicated that neomycin resistance in the E. coli transformants was due to the presence of the B. circulans phosphotransferase gene. This observation is consistent with the notion that anitbiotic-modifying enzymes from antibiotic-producing organisms may be the sources of antibiotic resistance in plasmid-containing bacteria. Images PMID:322154

Courvalin, P; Weisblum, B; Davies, J

1977-01-01

13

Crystal structure of cystalysin from Treponema denticola: a pyridoxal 5?-phosphate-dependent protein acting as a haemolytic enzyme  

PubMed Central

Cystalysin is a C?–S? lyase from the oral pathogen Treponema denticola catabolyzing l-cysteine to produce pyruvate, ammonia and H2S. With its ability to induce cell lysis, cystalysin represents a new class of pyridoxal 5?-phosphate (PLP)-dependent virulence factors. The crystal structure of cystalysin was solved at 1.9 ? resolution and revealed a folding and quaternary arrangement similar to aminotransferases. Based on the active site architecture, a detailed catalytic mechanism is proposed for the catabolism of S-containing amino acid substrates yielding H2S and cysteine persulfide. Since no homologies were observed with known haemolysins the cytotoxicity of cystalysin is attributed to this chemical reaction. Analysis of the cystalysin–l-aminoethoxyvinylglycine (AVG) complex revealed a ‘dead end’ ketimine PLP derivative, resulting in a total loss of enzyme activity. Cystalysin represents an essential factor of adult periodontitis, therefore the structure of the cystalysin–AVG complex may provide the chemical basis for rational drug design. PMID:10880431

Krupka, Heike I.; Huber, Robert; Holt, Stanley C.; Clausen, Tim

2000-01-01

14

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

15

Identification of a novel glycan processing enzyme with exo-acting ?-allosidase activity in the Golgi apparatus using a new platform for the synthesis of fluorescent substrates.  

PubMed

The majority of eukaryotic proteins undergo post-translational modifications (PTMs) involving the attachment of complex glycans, predominantly through N-glycosylation and O-glycosylation. PTMs play important roles in virtually all cellular processes, and aberrant regulation of protein glycosylation and glycan processing has been implicated in various diseases. However, glycan processing on proteins in various cellular contexts has not been visualized. We had previously developed a quinone methide cleavage (QMC) platform for enhanced substrate design. This platform was applied here to screen for novel glycan-processing enzymes. We designed and synthesized fluorescent substrates with ?-allopyranoside residues using the QMC platform. When applied in cell-based assays, the fluorescent substrates allowed rapid and clear visualization of ?-allosidase activity in the Golgi apparatus of human cultured cells. The QMC platform will likely find broad applications in visualizing the activities of glycan processing enzymes in living cells and in studying PTMs. PMID:25497961

Hakamata, Wataru; Miura, Kazuki; Hirano, Takako; Nishio, Toshiyuki

2015-01-01

16

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

17

In-Silico docking of HIV-1 integrase inhibitors reveals a novel drug type acting on an enzyme/DNA reaction intermediate  

PubMed Central

Background HIV-1 integrase (IN) is an emerging drug target, as IN strand transfer inhibitors (INSTIs) are proving potent antiretroviral agents in clinical trials. One credible theory sees INSTIs as docking at the cellular (acceptor) DNA-binding site after IN forms a transitional complex with viral (donor) DNA. However, mapping of the DNA and INSTI binding sites within the IN catalytic core domain (CCD) has been uncertain. Methods Structural superimpositions were conducted using the SWISS PDB and Cn3D free software. Docking simulations of INSTIs were run by a widely validated genetic algorithm (GOLD). Results Structural superimpositions suggested that a two-metal model for HIV-1 IN CCD in complex with small molecule, 1-(5-chloroindol-3-yl)-3-(tetrazoyl)-1,3-propandione-ene (5CITEP) could be used as a surrogate for an IN/viral DNA complex, because it allowed replication of contacts documented biochemically in viral DNA/IN complexes or displayed by a crystal structure of the IN-related enzyme Tn5 transposase in complex with transposable DNA. Docking simulations showed that the fitness of different compounds for the catalytic cavity of the IN/5CITEP complex significantly (P < 0.01) correlated with their 50% inhibitory concentrations (IC50s) in strand transfer assays in vitro. The amino acids involved in inhibitor binding matched those involved in drug resistance. Both metal binding and occupation of the putative viral DNA binding site by 5CITEP appeared to be important for optimal drug/ligand interactions. The docking site of INSTIs appeared to overlap with a putative acceptor DNA binding region adjacent to but distinct from the putative donor DNA binding site, and homologous to the nucleic acid binding site of RNAse H. Of note, some INSTIs such as 4,5-dihydroxypyrimidine carboxamides/N-Alkyl-5-hydroxypyrimidinone carboxamides, a highly promising drug class including raltegravir/MK-0518 (now in clinical trials), displayed interactions with IN reminiscent of those displayed by fungal molecules from Fusarium sp., shown in the 1990s to inhibit HIV-1 integration. Conclusion The 3D model presented here supports the idea that INSTIs dock at the putative acceptor DNA-binding site in a IN/viral DNA complex. This mechanism of enzyme inhibition, likely to be exploited by some natural products, might disclose future strategies for inhibition of nucleic acid-manipulating enzymes. PMID:17374162

Savarino, Andrea

2007-01-01

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

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

20

The RNA catabolic enzymes Rex4p, Rnt1p, and Dbr1p show genetic interaction with trans-acting factors involved in processing of ITS1 in Saccharomyces cerevisiae pre-rRNA.  

PubMed

Eukaryotes have two types of ribosomes containing either 5.8SL or 5.8SS rRNA that are produced by alternative pre-rRNA processing. The exact processing pathway for the minor 5.8SL rRNA species is poorly documented. We have previously shown that the trans-acting factor Rrp5p and the RNA exonuclease Rex4p genetically interact to influence the ratio between the two forms of 5.8S rRNA in the yeast Saccharomyces cerevisiae. Here we report a further analysis of ITS1 processing in various yeast mutants that reveals genetic interactions between, on the one hand, Rrp5p and RNase MRP, the endonuclease required for 5.8SS rRNA synthesis, and, on the other, Rex4p, the RNase III homolog Rnt1p, and the debranching enzyme Dbr1p. Yeast cells carrying a temperature-sensitive mutation in RNase MRP (rrp2-1) exhibit a pre-rRNA processing phenotype very similar to that of the previously studied rrp5-33 mutant: ITS2 processing precedes ITS1 processing, 5.8SL rRNA becomes the major species, and ITS1 is processed at the recently reported novel site A4 located midway between sites A2 and A3. As in the rrp5-Delta3 mutant, all of these phenotypical processing features disappear upon inactivation of the REX4 gene. Moreover, inactivation of the DBR1 gene in rrp2-1, or the RNT1 gene in rrp5-Delta3 mutant cells also negates the effects of the original mutation on pre-rRNA processing. These data link a total of three RNA catabolic enzymes, Rex4p, Rnt1p, and Dbr1p, to ITS1 processing and the relative production of 5.8SS and 5.8SL rRNA. A possible model for the indirect involvement of the three enzymes in yeast pre-rRNA processing is discussed. PMID:15525710

Faber, Alex W; Vos, Jan C; Vos, Harmjan R; Ghazal, Ghada; Elela, Sherif Abou; Raué, Hendrik A

2004-12-01

21

The RNA catabolic enzymes Rex4p, Rnt1p, and Dbr1p show genetic interaction with trans-acting factors involved in processing of ITS1 in Saccharomyces cerevisiae pre-rRNA  

PubMed Central

Eukaryotes have two types of ribosomes containing either 5.8SL or 5.8SS rRNA that are produced by alternative pre-rRNA processing. The exact processing pathway for the minor 5.8SL rRNA species is poorly documented. We have previously shown that the trans-acting factor Rrp5p and the RNA exonuclease Rex4p genetically interact to influence the ratio between the two forms of 5.8S rRNA in the yeast Saccharomyces cerevisiae. Here we report a further analysis of ITS1 processing in various yeast mutants that reveals genetic interactions between, on the one hand, Rrp5p and RNase MRP, the endonuclease required for 5.8SS rRNA synthesis, and, on the other, Rex4p, the RNase III homolog Rnt1p, and the debranching enzyme Dbr1p. Yeast cells carrying a temperature-sensitive mutation in RNase MRP (rrp2-1) exhibit a pre-rRNA processing phenotype very similar to that of the previously studied rrp5-33 mutant: ITS2 processing precedes ITS1 processing, 5.8SL rRNA becomes the major species, and ITS1 is processed at the recently reported novel site A4 located midway between sites A2 and A3. As in the rrp5-?3 mutant, all of these phenotypical processing features disappear upon inactivation of the REX4 gene. Moreover, inactivation of the DBR1 gene in rrp2-1, or the RNT1 gene in rrp5-?3 mutant cells also negates the effects of the original mutation on pre-rRNA processing. These data link a total of three RNA catabolic enzymes, Rex4p, Rnt1p, and Dbr1p, to ITS1 processing and the relative production of 5.8SS and 5.8SL rRNA. A possible model for the indirect involvement of the three enzymes in yeast pre-rRNA processing is discussed. PMID:15525710

FABER, ALEX W.; VOS, JAN C.; VOS, HARMJAN R.; GHAZAL, GHADA; ABOU ELELA, SHERIF; RAUÉ, HENDRIK A.

2004-01-01

22

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

23

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

24

Glutathione Degradation by the Alternative Pathway (DUG Pathway) in Saccharomyces cerevisiae Is Initiated by (Dug2p-Dug3p)2 Complex, a Novel Glutamine Amidotransferase (GATase) Enzyme Acting on Glutathione*  

PubMed Central

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

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

2012-01-01

25

Enzyme Reactions  

NSDL National Science Digital Library

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

Maryland Virtual High School

26

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

27

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

28

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

29

Engineering enzymes.  

PubMed

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

Dutton, P Leslie; Moser, Christopher C

2011-01-01

30

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

31

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

32

Enzymes as Chemotherapeutic Agents Ronald T. Raines  

E-print Network

agents act by disrupting the flow of biochemical information (Fig. 1). The most common strategy uses small organic molecules to inhibit the function of a protein. Information flow can be disrupted at the RNA level to treat eye infections caused by cytomegalovirus. Can enzymes act as chemotherapeutic

Raines, Ronald T.

33

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

34

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

35

Recent advances in sulfotransferase enzyme activity assays  

PubMed Central

Sulfotransferases are enzymes that catalyze the transfer of sulfo groups from a donor, for example 3?-phosphoadenosine 5?-phosphosulfate, to an acceptor, for example the amino or hydroxyl groups of a small molecule, xenobiotic, carbohydrate, or peptide. These enzymes are important targets in the design of novel therapeutics for treatment of a variety of diseases. This review examines assays used for this important class of enzyme, paying particular attention to sulfotransferases acting on carbohydrates and peptides and the major challenges associated with their analysis. PMID:22526635

Paul, Priscilla; Suwan, Jiraporn; Liu, Jian; Dordick, Jonathan S.

2012-01-01

36

Extracellular Enzymes Lab Biochemistry  

E-print Network

Extracellular Enzymes Lab Biochemistry · All organisms convert small organic compounds, of which there are more than 1000, are catalyzed by enzymes. Glucose (C6) Pentose (C5) Triose (C3) Pyruvate Complete Metabolic Network TOP #12;#12;Enzymes · Enzymes are large proteins that all organisms synthesize

Vallino, Joseph J.

37

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

38

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

39

Novel enzymes for the degradation of cellulose  

PubMed Central

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

2012-01-01

40

Novel enzymes for the degradation of cellulose.  

PubMed

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

Horn, Svein Jarle; Vaaje-Kolstad, Gustav; Westereng, Bjørge; Eijsink, Vincent Gh

2012-01-01

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 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.

43

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.

44

Advances in enzyme immobilisation.  

PubMed

Improvements in current strategies for carrier-based immobilisation have been developed using hetero-functionalised supports that enhance the binding efficacy and stability through multipoint attachment. New commercial resins (Sepabeads) exhibit improved protein binding capacity. Novel methods of enzyme self-immobilisation have been developed (CLEC, CLEA, Spherezyme), as well as carrier materials (Dendrispheres), encapsulation (PEI Microspheres), and entrapment. Apart from retention, recovery and stabilisation, other advantages to enzyme immobilisation have emerged, such as enhanced enzyme activity, modification of substrate selectivity and enantioselectivity, and multi-enzyme reactions. These advances promise to enhance the roles of immobilisation enzymes in industry, while opening the door for novel applications. PMID:19590826

Brady, Dean; Jordaan, Justin

2009-11-01

45

Profiling the orphan enzymes  

PubMed Central

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

2014-01-01

46

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

47

Direct in Situ Observation of Synergism between Cellulolytic Enzymes during the Biodegradation of Crystalline Cellulose Fibers  

E-print Network

Direct in Situ Observation of Synergism between Cellulolytic Enzymes during the Biodegradation types of T. reesei cellulolytic enzymes TrCel6A, TrCel7A, and TrCel7Band their mixtures. TrCel6A and Tr. When acting alone on native cellulose fibers, each of the three enzymes is incapable of significant

Dutcher, John

48

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

49

Adenylate-forming enzymes  

PubMed Central

Thioesters, amides and esters are common chemical building blocks in a wide array of natural products. The formation of these bonds can be catalyzed in a variety of ways. For chemists, the use of an activating group is a common strategy and adenylate enzymes are exemplars of this approach. Adenylating enzymes activate the otherwise unreactive carboxylic acid by transforming the normal hydroxyl leaving group into adenosine monophosphate. Recently there have been a number of studies of such enzymes and in this review we suggest a new classification scheme. The review highlights the diversity in enzyme fold, active site architecture and metal coordination that has evolved to catalyze this particular reaction. PMID:19836944

Schmelz, Stefan; Naismith, James H.

2012-01-01

50

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

51

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

52

Enzymes on material surfaces.  

PubMed

Enzyme interactions with material surfaces are of interest for industrial food and pharmaceutical transformations, biosensors, artificial cells, cell free reactions, drug and nutrition delivery technologies, and imaging. When in contact with a material surface, an enzyme may lose or appear to lose activity due to the nature of the enzyme, the nature of the material, and/or the nature of the interface between the enzyme, material, and substrate environment. The purpose of this review is to survey recent advances that have been made towards the preservation, optimization, and enhancement of enzyme activity on material surfaces within the context of well-known concepts that describe the loss of activity after immobilization. This review breaks down the immobilized enzyme system to look at the individual components of the system-namely the enzyme, the material, and the interface. For each piece, possible causes for the loss of enzyme activity are described as well as strategies that have been applied to limit the affect. At the conclusion we identify areas of future research needed to overcome limitations in the current state-of-the art for immobilized enzyme systems. PMID:22269888

Talbert, Joey N; Goddard, Julie M

2012-05-01

53

A stimulatory RNA associated with RecBCD enzyme.  

PubMed Central

RecBCD enzyme acts in the major pathway of homologous recombination of linear DNA in Escherichia coli. The enzyme unwinds DNA and is an ATP-dependent double-strand and single-strand exonuclease and a single-strand endonuclease; it acts at Chi recombination hotspots (5'-GCTGGTGG-3') to produce a recombinogenic single-stranded DNA 3'-end. We found that a small RNA with a unique sequence of approximately 24 nt was tightly bound to RecBCD enzyme and co-purified with it. When added to native enzyme this RNA, but not four others, increased DNA unwinding and Chi nicking activities of the enzyme. In seven similarly active enzyme preparations the molar ratio of RNA molecules to RecBCD enzyme molecules ranged from 0.2 to <0.008. These results suggest that, although this unique RNA is not an essential enzyme subunit, it has a biological role in stimulating RecBCD enzyme activity. PMID:9547270

Amundsen, S K; Taylor, A F; Smith, G R

1998-01-01

54

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

55

Terminology of Enzyme Formation  

Microsoft Academic Search

IT has been recognized for many years that in micro-organisms the formation of a large variety of enzymes can be specifically induced by exposing cells to compounds which are substrates for the enzymes in question. Recently, the same phenomenon has been demonstrated in a mammal1, and it will probably prove to be a general property of biological systems. Since a

M. Cohn; J. Monod; M. R. POLLOCK; S. SPIEGELMAN; R. Y. STANIER

1953-01-01

56

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

57

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

58

Cellulose degradation by oxidative enzymes.  

PubMed

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

59

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.

60

Chemotactic separation of enzymes.  

PubMed

We demonstrate a procedure for the separation of enzymes based on their chemotactic response toward an imposed substrate concentration gradient. The separation is observed within a two-inlet, five-outlet microfluidic network, designed to allow mixtures of active (ones that catalyze substrate turnover) and inactive (ones that do not catalyze substrate turnover) enzymes, labeled with different fluorophores, to flow through one of the inlets. Substrate solution prepared in phosphate buffer was introduced through the other inlet of the device at the same flow rate. The steady-state concentration profiles of the enzymes were obtained at specific positions within the outlets of the microchannel using fluorescence microscopy. In the presence of a substrate concentration gradient, active enzyme molecules migrated preferentially toward the substrate channel. The excess migration of the active enzyme molecules was quantified in terms of an enrichment coefficient. Experiments were carried out with different pairs of enzymes. Coupling the physics of laminar flow of liquid and molecular diffusion, multiphysics simulations were carried out to estimate the extent of the chemotactic separation. Our results show that, with appropriate microfluidic arrangement, molecular chemotaxis leads to spontaneous separation of active enzyme molecules from their inactive counterparts of similar charge and size. PMID:25243599

Dey, Krishna Kanti; Das, Sambeeta; Poyton, Matthew F; Sengupta, Samudra; Butler, Peter J; Cremer, Paul S; Sen, Ayusman

2014-12-23

61

Structure and Function of Glucansucrases  

Microsoft Academic Search

Glucansucrases are relatively large (~160 kDa) extracellular enzymes produced by lactic acid bacteria. Using sucrose as a substrate they synthesize high molecular mass glucose polymers, called alpha-glucans, which allow the bacteria to adhere to surfaces and create a biofilm. The glucan polymers are of importance for the food and dairy industry as thickening and jellying agents. An overview is given

B. W. Dijkstra; A. Vujicic-Zagar

2008-01-01

62

Enzyme and microbial sensors for environmental monitoring  

NASA Astrophysics Data System (ADS)

Biosensors employing the biocatalyst on a different level of integration have been developed for monitoring environmental pollution. These probes range from laboratory specimen to commercial detectors applied to analyzers. This paper presents a selection of recent developments on amperometric enzyme and microbial biosensors. A monoenzymatic bulk type carbon electrode is described for biosensing organic hydroperoxides in aqueous solutions. Here, peroxidase is immobilized within the electrode body and the direct electron transfer between electrode and enzyme is measured. Both, reversible and irreversible inhibitors of acetylcholinesterase have been quantified by using a kinetically controlled acetylcholine enzyme sequence electrode. The inhibitory effect of pesticides such as butoxycarboxime, dimethoate, and trichlorfon could be quantified within 6 min in micrometers olar concentrations. Different multi-enzyme electrodes have been developed for the determination of inorganic phosphate. These sensors represent examples of sequentially acting enzymes in combination with enzymatic analyte recycling. Using this type of amplification nanomolar concentrations could be measured. A very fast responding microbial sensor for biological oxygen demand has been developed by immobilizing Trichosporon cutaneum onto an oxygen electrode. With this whole cell sensor waste water can be assayed with a sample frequency of 20 per hour and a working stability of more than 30 days.

Wollenberger, U.; Neumann, B.; Scheller, Frieder W.

1993-03-01

63

RNA as an Enzyme.  

ERIC Educational Resources Information Center

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

Cech, Thomas R.

1986-01-01

64

Forgetting ACT UP  

ERIC Educational Resources Information Center

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

Juhasz, Alexandra

2012-01-01

65

RNA-modifying enzymes.  

PubMed

A bewildering number of post-transcriptional modifications are introduced into cellular RNAs by enzymes that are often conserved among archaea, bacteria and eukaryotes. The modifications range from those with well-understood functions, such as tRNA aminoacylation, to widespread but more mysterious ones, such as pseudouridylation. Recent structure determinations have included two types of RNA nucleobase modifying enzyme: pseudouridine synthases and tRNA guanine transglycosylases. PMID:12581659

Ferré-D'Amaré, Adrian R

2003-02-01

66

Enzymes and Their Functions  

NSDL National Science Digital Library

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

Bioengineering, Climb: C.

67

Overproduction of ligninolytic enzymes  

SciTech Connect

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

Elisashvili, Vladimir; Kachlishvili, Eva; Torok, Tamas

2014-06-17

68

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

69

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

70

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

71

ACTS propagation terminal update  

NASA Technical Reports Server (NTRS)

The activities at Virginia Polytechnic Institute and State University in preparation for the February 1993 launch of ACTS are summarized. ACTS propagation terminals (APT) are being constructed to receive the 20 and 27.5 GHz ACTS beacon signals. Total power radiometers operating at the same frequencies are integrated into the terminal for use in level setting. Recent progress and plans for APT's are reported.

Stutzman, Warren L.; Pratt, Tim

1992-01-01

72

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

73

Caught in the act  

PubMed Central

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

2013-01-01

74

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

75

An isoelectrically trapped enzyme reactor operating in an electric field.  

PubMed

Membrane enzyme reactors constitute an attempt at integrating catalytic conversion, product separation and/or concentration and catalyst recovery into a single operation. Whereas conventional membrane reactors confine an enzyme, in a free form, to one side of a membrane by size exclusion, electrostatic repulsion, or physical or chemical immobilization onto an intermediate support (gel, liposome), the membrane reactor here described is shown to operate under an entirely new principle: enzyme confinement into an isoelectric trap located in a multicompartment electrolyzer operating in an electric field. Two isoelectric membranes, having pI values encompassing both the enzyme pI and the pH of its optimum of activity, act by continuously titrating the enzyme trapped inside, thus preventing it from escaping the reaction chamber. Charged products generated by the enzyme catalysis are continuously electrophoretically transported away from the reaction chamber and collected into other chambers stacked either towards the cathodic or anodic sides. In a urease reactor, ammonia is continuously harvested towards the cathode, thus allowing >95% substrate consumption with maintenance of enzyme integrity over much longer time periods than in a batch reactor. In a trypsin reactor, casein is digested and biologically active peptides are continuously harvested in a pure form into appropriate isoelectric traps. In a third example, pure D-phenylglycine is produced from a racemate mixture, via an acylation reaction onto a cosubstrate (the ester methyl-4-hydroxyphenyl acetate), brought about by the enzyme penicillin G acylase. PMID:9662167

Righetti, P G; Bossi, A

1998-06-01

76

Bacterial Sulfite-Oxidizing Enzymes – Enzymes for Chemolithotrophs Only?  

Microsoft Academic Search

All known sulfite-oxidizing enzymes that have been studied in molecular detail belong to the sulfite oxidase family of molybdoenzymes.\\u000a The first bacterial enzymes in this family were only characterized in 2000, but by now it has become clear that bacterial\\u000a enzymes originating from many different types of bacteria may actually be the most abundant proteins in this enzyme family.\\u000a This

Ulrike Kappler

77

Enzyme reactions in a multicompartment electrolyzer with isoelectrically trapped enzymes  

Microsoft Academic Search

The possibility of performing bioconversions under an electric field is here reported. A system is described by which the enzyme is trapped by an isoelectric mechanism between two zwitterionic membranes having pI values encompassing the isoelectric point of the enzyme. The enzyme is loaded into a multicompartment electrolyzer and kept operating under an electric field, which will continuously harvest the

Marcella Chiari; Norma Dell'Orto; Monica Mendozza; Giacomo Carrea; Pier Giorgio Righetti

1996-01-01

78

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

79

Analysis of Enzyme Kinetic Data Analysis of Enzyme Kinetic Data  

E-print Network

Analysis of Enzyme Kinetic Data #12;To Marilú #12;Analysis of Enzyme Kinetic Data ATHEL CORNISH., without restriction. It will be appreciated, however, if any use of it in published work is apopropriately provide a theoretical account of statistical analysis of kinetic data for enzyme-catalysed reactions

80

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

81

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

82

Older Americans Act  

MedlinePLUS

... 1326 (Title VI) Grants to Indian Tribes for Support and Nutrition Services Older Americans Act Regulations (1988), 45 CFR Part 1328 (Title VI) Grants for Supportive and Nutritional Services to Older Hawaiian Natives Programs Older Americans ...

83

Assertive Community Treatment (ACT)  

MedlinePLUS

... model of an inpatient psychiatric unit, which includes nurses, psychiatrists, social workers, case managers, occupational therapists and ... ACT is indicated for individuals of all ages, gender and ethnicity with severe and persistent mental illness. ...

84

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

85

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

86

The Catalytic Function of Enzymes.  

ERIC Educational Resources Information Center

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

Splittgerber, Allan G.

1985-01-01

87

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

88

REBASE - restriction enzymes and methylases  

Microsoft Academic Search

REBASE contains comprehensive information about restriction enzymes, DNA methylases and related proteins such as nicking enzymes, specificity subunits and control proteins. It contains published and unpublished references, recognition and cleavage sites, isoschizomers, commercial availability, methy- lation sensitivity, crystal data and sequence data. Homing endonucleases are also included. Most recently, extensive information about the methylation sensitivity of restriction enzymes has been

Richard J. Roberts; Dana Macelis

2001-01-01

89

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

PubMed

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

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

2013-12-01

90

Purification and characterization of a fibrinolytic enzyme from Petasites japonicus.  

PubMed

A new, direct-acting chymotrypsin-like fibrinolytic serine protease was purified from Petasites japonicus, a medicinal herb. The molecular mass of the discovered enzyme was estimated to be 40.0 kDa as determined using sodium dodecyl sulfate polyacrylamide gel electrophoresis, fibrin zymography, and gel filtration chromatography. The N-terminal sequence of the purified enzyme was determined to be GQEDHFLQVSLTSA. The proteolytic activity of the enzyme was found to be inhibited by serine protease inhibitors phenylmethylsulfonyl fluoride and 4-(amidinophenyl) methanesulfonyl fluoride. An assay of enzyme activity on fibrin plates revealed that it could hydrolyze the fibrin directly. The enzyme displayed a potent fibrin(ogen)olytic activity, hydrolyzing the A?-, ?-, and B?-subunits of the human fibrinogen. The enzyme prolonged activated partial thromboplastin time and had little effect on prothrombin time. It prevented carrageenan-induced thrombus formation in mouse tails and did not increase the bleeding time. Our findings indicate that the extracted enzyme we present here has the potential for clinical use as an agent for the treatment of thrombosis. PMID:25316419

Kim, Dae-Won; Choi, Jun-Hui; Park, Se-Eun; Kim, Seung; Sapkota, Kumar; Kim, Sung-Jun

2015-01-01

91

STUDIES ON ENZYME ACTION  

PubMed Central

The saccharogenic enzymes present in potato juice were studied. The actions were followed upon the substances present in the juice and upon added sucrose, maltose, and soluble starch. Sucrase and amylase were found to be present in the juice. No indication of a maltase was obtained. The sucrase showed optimum conditions for action at pH 4 to 5, the amylase at pH 6 to 7, both upon the starch present in the juice and upon added soluble starch. The action of a yeast sucrase preparation upon the juice showed the presence of sucrose (or raffinose) in a concentration of the order of magnitude of 1 per cent. PMID:19871804

McGuire, Grace; Falk, K. George

1920-01-01

92

STUDIES ON ENZYME ACTION  

PubMed Central

A number of different methods of treatment of unripe and ripe bananas for the purpose of obtaining and studying sucrolytic and amylolytic enzymes are described. No conclusive evidence of the presence of an amlyase could be obtained in any of the preparations. The sucrase of unripe and ripe bananas was studied more extensively. With ripe bananas, both soluble and insoluble sucrase preparations were obtained. Conditions for converting the soluble into an insoluble form were found. The actions of the sucrase preparations as far as the hydrogen ion concentration for maximum action and the time-action relation are concerned are similar to the behavior of the yeast and the potato sucrase. PMID:19871890

Falk, K. George; McGuire, Grace

1921-01-01

93

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

94

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

95

The ACTS multibeam antenna  

NASA Technical Reports Server (NTRS)

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

Regier, Frank A.

1992-01-01

96

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

97

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

98

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

99

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

Code of Federal Regulations, 2014 CFR

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

2014-01-01

100

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

101

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

102

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

103

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

104

Acting like a Pro  

ERIC Educational Resources Information Center

The Saturday morning acting class in the Pearson Hall auditorium at Miles College boasts the school's highest attendance all year. The teacher, actress Robin Givens, was a lure few students--and others from surrounding areas--could resist. Some came to learn about their prospective field from a professional. Others were there for pointers to…

Walker, Marlon A.

2012-01-01

105

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

106

Hydrolytic enzymes of "Streptococcus milleri".  

PubMed Central

Seventy-two isolates classified as "Streptococcus milleri" were examined for the presence of various hydrolytic enzymes. While no protein or lipid-degrading activities were demonstrated, some isolates showed DNase and mucopolysaccharide-degrading activities. Beta-hemolytic isolates were more likely to produce these enzymes than were nonhemolytic strains. Isolates of one "S. milleri" biotype (mannitol fermentation positive) were uniformly devoid of all enzyme activities tested. PMID:2958496

Ruoff, K L; Ferraro, M J

1987-01-01

107

Immobilized Cell and Enzyme Technology  

NASA Astrophysics Data System (ADS)

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

Dunnill, P.

1980-08-01

108

Enzymes Help Us Digest Food  

NSDL National Science Digital Library

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

Doherty, Jennifer; Waldron, Ingrid

109

Phage lytic enzymes: a history.  

PubMed

There are many recent studies regarding the efficacy of bacteriophage-related lytic enzymes: the enzymes of 'bacteria-eaters' or viruses that infect bacteria. By degrading the cell wall of the targeted bacteria, these lytic enzymes have been shown to efficiently lyse Gram-positive bacteria without affecting normal flora and non-related bacteria. Recent studies have suggested approaches for lysing Gram-negative bacteria as well (Briersa Y, et al., 2014). These enzymes include: phage-lysozyme, endolysin, lysozyme, lysin, phage lysin, phage lytic enzymes, phageassociated enzymes, enzybiotics, muralysin, muramidase, virolysin and designations such as Ply, PAE and others. Bacteriophages are viruses that kill bacteria, do not contribute to antimicrobial resistance, are easy to develop, inexpensive to manufacture and safe for humans, animals and the environment. The current focus on lytic enzymes has been on their use as anti-infectives in humans and more recently in agricultural research models. The initial translational application of lytic enzymes, however, was not associated with treating or preventing a specific disease but rather as an extraction method to be incorporated in a rapid bacterial detection assay (Bernstein D, 1997).The current review traces the translational history of phage lytic enzymes-from their initial discovery in 1986 for the rapid detection of group A streptococcus in clinical specimens to evolving applications in the detection and prevention of disease in humans and in agriculture. PMID:25662888

Trudil, David

2015-02-01

110

Integrated microdroplet-based system for enzyme synthesis and sampling  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

111

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

112

Thermus aquaticus ATCC 33923 Amylomaltase Gene Cloning and Expression and Enzyme Characterization: Production of Cycloamylose  

PubMed Central

The amylomaltase gene of the thermophilic bacterium Thermus aquaticus ATCC 33923 was cloned and sequenced. The open reading frame of this gene consisted of 1,503 nucleotides and encoded a polypeptide that was 500 amino acids long and had a calculated molecular mass of 57,221 Da. The deduced amino acid sequence of the amylomaltase exhibited a high level of homology with the amino acid sequence of potato disproportionating enzyme (D-enzyme) (41%) but a low level of homology with the amino acid sequence of the Escherichia coli amylomaltase (19%). The amylomaltase gene was overexpressed in E. coli, and the enzyme was purified. This enzyme exhibited maximum activity at 75°C in a 10-min reaction with maltotriose and was stable at temperatures up to 85°C. When the enzyme acted on amylose, it catalyzed an intramolecular transglycosylation (cyclization) reaction which produced cyclic ?-1,4-glucan (cycloamylose), like potato D-enzyme. The yield of cycloamylose produced from synthetic amylose with an average molecular mass of 110 kDa was 84%. However, the minimum degree of polymerization (DP) of the cycloamylose produced by T. aquaticus enzyme was 22, whereas the minimum DP of the cycloamylose produced by potato D-enzyme was 17. The T. aquaticus enzyme also catalyzed intermolecular transglycosylation of maltooligosaccharides. A detailed analysis of the activity of T. aquaticus ATCC 33923 amylomaltase with maltooligosaccharides indicated that the catalytic properties of this enzyme differ from those of E. coli amylomaltase and the plant D-enzyme. PMID:10049841

Terada, Yoshinobu; Fujii, Kazutoshi; Takaha, Takeshi; Okada, Shigetaka

1999-01-01

113

ACTS of Education  

NASA Technical Reports Server (NTRS)

Now in its ninth year of operations, the Advanced Communications Technology Satellite (ACTS) program has continued, although since May 2000 in a new operations arrangement involving a university based consortium, the Ohio Consortium for Advanced Communications Technology (OCACT), While NASA has concluded its experimental intentions of ACTS, the spacecraft's ongoing viability has permitted its further operations to provide educational opportunities to engineering and communications students interested in satellite operations, as well as a Ka-band test bed for commercial interests in utilizing Kaband space communications. The consortium has reached its first year of operations. This generous opportunity by NASA has already resulted in unique educational opportunities for students in obtaining "hands-on" experience, such as, in satellite attitude control. An update is presented on the spacecraft and consortium operations.

Bauer, Robert; Krawczyk, Richard; Gargione, Frank; Kruse, Hans; Vrotsos, Pete (Technical Monitor)

2002-01-01

114

The Wilderness Act Handbook  

NSDL National Science Digital Library

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

115

Safety Regulations of Food Enzymes  

Microsoft Academic Search

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

Armin Spök

116

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

117

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

118

REBASE: restriction enzymes and methyltransferases  

Microsoft Academic Search

REBASE contains comprehensive information about restriction enzymes, DNA methyltransferases and related proteins such as nicking enzymes, specificity subunits and control proteins. It contains published and unpublished references, recognition and clea- vage sites, isoschizomers, commercial availability, crystal and sequence data. Homing endonucleases are also included. REBASE contains the most complete and up-to-date information about the methylation sensitivity of restriction endonucleases. In

Richard J. Roberts; Tamas Vincze; Janos Posfai; Dana Macelis

2003-01-01

119

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

120

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,

121

Remodeling of sphingolipids by plasma membrane associated enzymes.  

PubMed

The sphingolipid plasma membrane content and pattern is the result of several processes, among which the main, in term of quantity, are: neo-biosynthesis in endoplasmic reticulum and Golgi apparatus, membrane turnover with final catabolism in lysosomes and membrane shedding. In addition to this, past and recent data suggest that the head group of sphingolipids can be opportunely modified at the plasma membrane level, probably inside specific membrane lipid domains, by the action of enzymes involved in the sphingolipids metabolism, working directly at the cell surface. The number of membrane enzymes, hydrolases and transferases, acting on membrane sphingolipids is growing very rapidly. In this report we describe some properties of these enzymes. PMID:21181265

Aureli, Massimo; Loberto, Nicoletta; Chigorno, Vanna; Prinetti, Alessandro; Sonnino, Sandro

2011-09-01

122

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

123

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

124

Cleaning Up Your Act  

NSDL National Science Digital Library

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

Donna King

2012-08-01

125

Military Veterans (Affordable Care Act)  

MedlinePLUS

... Contact Us Site Search Search Military veterans Health care coverage options for military veterans If you're ... adult coverage rules are different from the Affordable Care Act’s version. TRICARE's young adult coverage option is ...

126

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

127

ACT Directory of Aboriginal and  

E-print Network

Capital Territory, Canberra, 2010 This work is copyright. Apart from any use as permitted under. GPO Box 158, Canberra City ACT 2601 Produced by Publishing Services for the Department of Disability Box 158 CANBERRA ACT 2601 Phone: (02) 6207 0555 Web: www.dhcs.act.gov.au Disclaimer The Department

Botea, Adi

128

PROHIBITED ACTSPROHIBITED ACTS (a) GENERAL.-  

E-print Network

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

129

Microtubule-severing enzymes at the cutting edge.  

PubMed

ATP-dependent severing of microtubules was first reported in Xenopus laevis egg extracts in 1991. Two years later this observation led to the purification of the first known microtubule-severing enzyme, katanin. Katanin homologs have now been identified throughout the animal kingdom and in plants. Moreover, members of two closely related enzyme subfamilies, spastin and fidgetin, have been found to sever microtubules and might act alongside katanins in some contexts (Roll-Mecak and McNally, 2010; Yu et al., 2008; Zhang et al., 2007). Over the past few years, it has become clear that microtubule-severing enzymes contribute to a wide range of cellular activities including mitosis and meiosis, morphogenesis, cilia biogenesis and disassembly, and migration. Thus, this group of enzymes is revealing itself to be among the most important of the microtubule regulators. This Commentary focuses on our growing understanding of how microtubule-severing enzymes contribute to the organization and dynamics of diverse microtubule arrays, as well as the structural and biophysical characteristics that afford them the unique capacity to catalyze the removal of tubulin from the interior microtubule lattice. Our goal is to provide a broader perspective, focusing on a limited number of particularly informative, representative and/or timely findings. PMID:22595526

Sharp, David J; Ross, Jennifer L

2012-06-01

130

21 CFR 864.4400 - Enzyme preparations.  

Code of Federal Regulations, 2014 CFR

... 2014-04-01 2014-04-01 false Enzyme preparations. 864.4400 Section 864...Specimen Preparation Reagents § 864.4400 Enzyme preparations. (a) Identification. Enzyme preparations are products that are...

2014-04-01

131

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

132

21 CFR 864.4400 - Enzyme preparations.  

Code of Federal Regulations, 2012 CFR

... 2012-04-01 2012-04-01 false Enzyme preparations. 864.4400 Section 864...Specimen Preparation Reagents § 864.4400 Enzyme preparations. (a) Identification. Enzyme preparations are products that are...

2012-04-01

133

21 CFR 864.4400 - Enzyme preparations.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 2011-04-01 false Enzyme preparations. 864.4400 Section 864...Specimen Preparation Reagents § 864.4400 Enzyme preparations. (a) Identification. Enzyme preparations are products that are...

2011-04-01

134

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

135

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;

136

Regulation of Proteolysis by Human Deubiquitinating Enzymes  

PubMed Central

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

Eletr, Ziad M.; Wilkinson, Keith D.

2013-01-01

137

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...

138

Molybdenum cofactors, enzymes and pathways  

Microsoft Academic Search

The trace element molybdenum is essential for nearly all organisms and forms the catalytic centre of a large variety of enzymes such as nitrogenase, nitrate reductases, sulphite oxidase and xanthine oxidoreductases. Nature has developed two scaffolds holding molybdenum in place, the iron-molybdenum cofactor and pterin-based molybdenum cofactors. Despite the different structures and functions of molybdenum-dependent enzymes, there are important similarities,

Günter Schwarz; Ralf R. Mendel; Markus W. Ribbe

2009-01-01

139

Gene Cloning and Expression and Secretion of Listeria monocytogenes Bacteriophage-Lytic Enzymes in Lactococcus lactis  

Microsoft Academic Search

Bacteriophage lysins (Ply), or endolysins, are phage-encoded cell wall lytic enzymes which are synthesized late during virus multiplication and mediate the release of progeny virions. Bacteriophages of the pathogen Listeria monocytogenes encode endolysin enzymes which specifically hydrolyze the cross-linking peptide bridges in Listeria peptidoglycan. Ply118 is a 30.8-kDa L-alanoyl-D-glutamate peptidase and Ply511 (36.5 kDa) acts as N-acetylmuramoyl-L-alanine amidase. In order

SUSANNE GAENG; SIEGFRIED SCHERER; HORST NEVE; MARTIN J. LOESSNER

2000-01-01

140

Computational Modelling of a Sensor Based on an Array of Enzyme Microreactors  

Microsoft Academic Search

This paper presents a two-dimensional-in-space mathematical model of a sensor system based an array of enzyme microreactors immobilised on a single electrode. The system acts under amperometric conditions. The model is based on the diffusion equations containing a non-linear term related to the Michaelis-Menten kinetics of the enzymatic reaction. The model involves three regions: an array of enzyme microreactors (cells)

R. Baronas; F. Ivanauskas; J. Kulys; M. Sapagovas

2004-01-01

141

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

142

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

143

Medium molecular weight factor X activating enzyme from Vipera berus berus venom.  

PubMed

Vipera berus berus venom contains several factor X activating enzymes. One of them (VBFXAE) was separated by gel-filtration on Sephadex G-100 superfine and on a bacitracin-agarose column. The enzyme is a single-chain glycoprotein with mol. wt 38,000. The enzyme has several molecular forms with pI 3.5-4.5. After neuraminidase treatment the enzyme has pI 4.5. VBFXAE contains 2 Ca per mole. The activator is inactive on synthetic substrates, on casein, prothrombin, and fibrinogen, and appears to act specifically on factor X. The activator also weakly hydrolyses the insulin B-chain at the positions Ala14-Leu15 and Tyr16-Leu17. The cleavage of the insulin B-chain is inhibited by EDTA, suggesting the metalloproteinase nature of the enzyme. PMID:7778128

Samel, M; Siigur, J

1995-01-01

144

Double acting bit holder  

DOEpatents

A double acting bit holder that permits bits held in it to be resharpened during cutting action to increase energy efficiency by reducing the amount of small chips produced. The holder consist of: a stationary base portion capable of being fixed to a cutter head of an excavation machine and having an integral extension therefrom with a bore hole therethrough to accommodate a pin shaft; a movable portion coextensive with the base having a pin shaft integrally extending therefrom that is insertable in the bore hole of the base member to permit the moveable portion to rotate about the axis of the pin shaft; a recess in the movable portion of the holder to accommodate a shank of a bit; and a biased spring disposed in adjoining openings in the base and moveable portions of the holder to permit the moveable portion to pivot around the pin shaft during cutting action of a bit fixed in a turret to allow front, mid and back positions of the bit during cutting to lessen creation of small chip amounts and resharpen the bit during excavation use.

Morrell, Roger J. (Blommington, MN); Larson, David A. (Minneapolis, MN); Ruzzi, Peter L. (Eagan, MN)

1994-01-01

145

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

146

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.

147

Investigation of Lasso Peptides Maturation Enzymes  

E-print Network

Investigation of Lasso Peptides Maturation Enzymes Ángel L. Placeres PCCM/PRISM 2012 REU. · Unable to make Astexin-1 in vitro. · Strong possibility that Astexin-1 enzymes are better behaved than the MccJ25 enzymes. #12;Astic C · Maturation Enzyme. · Part of the gene cluster that helps make the lasso

Petta, Jason

148

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

149

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

150

REBASE - restriction enzymes and methylases.  

PubMed Central

REBASE is a comprehensive database of information about restriction enzymes and their associated methylases, including their recognition and cleavage sites and their commercial availability. Also included is a listing of homing endonucleases. Information from REBASE is available via monthly electronic mailings as well as via anonymous ftp and through the World Wide Web. The REBASE web site, http://www. neb.com/rebase , is where we maintain a web page for every enzyme, reference and supplier. Additionally, there is a search facility, help and NEWS pages, and a complete description of our various services. Specialized files are available that can be used directly by many software packages. PMID:9399870

Roberts, R J; Macelis, D

1998-01-01

151

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

152

Internal friction in enzyme reactions.  

PubMed

The empirical concept of internal friction was introduced 20 years ago. This review summarizes the results of experimental and theoretical studies that help to uncover the nature of internal friction. After the history of the concept, we describe the experimental challenges in measuring and interpreting internal friction based on the viscosity dependence of enzyme reactions. We also present speculations about the structural background of this viscosity dependence. Finally, some models about the relationship between the energy landscape and internal friction are outlined. Alternative concepts regarding the viscosity dependence of enzyme reactions are also discussed. PMID:23281036

Rauscher, Anna; Derényi, Imre; Gráf, László; Málnási-Csizmadia, András

2013-01-01

153

The fluctuating enzyme: a single molecule approach  

NASA Astrophysics Data System (ADS)

The excess of structural degrees of freedom in a protein enzyme opens questions about the conformational homogeneity. We studied single horseradish peroxidase enzyme turnovers by fluorescence spectroscopy. Application of a two-state dynamic model to the measured data shows exponential product dissociation kinetics, but a large distribution of rates for the enzyme to form the enzyme-product complex. The experiments show that in addition to the peroxidative cycle thermodynamic fluctuation phenomena on a wide range of time scales affect enzyme activity.

Edman, Lars; Földes-Papp, Zeno; Wennmalm, Stefan; Rigler, Rudolf

1999-08-01

154

7 CFR 63.1 - Act.  

Code of Federal Regulations, 2012 CFR

...REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) NATIONAL SHEEP INDUSTRY IMPROVEMENT CENTER General Provisions Definitions § 63.1 Act. Act means section 375 of the...

2012-01-01

155

7 CFR 63.1 - Act.  

Code of Federal Regulations, 2014 CFR

...REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) NATIONAL SHEEP INDUSTRY IMPROVEMENT CENTER General Provisions Definitions § 63.1 Act. Act means section 375 of the...

2014-01-01

156

7 CFR 63.1 - Act.  

Code of Federal Regulations, 2013 CFR

...REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) NATIONAL SHEEP INDUSTRY IMPROVEMENT CENTER General Provisions Definitions § 63.1 Act. Act means section 375 of the...

2013-01-01

157

7 CFR 63.1 - Act.  

Code of Federal Regulations, 2011 CFR

...REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) NATIONAL SHEEP INDUSTRY IMPROVEMENT CENTER General Provisions Definitions § 63.1 Act. Act means section 375 of the...

2011-01-01

158

Inhibitors of testosterone biosynthetic and metabolic activation enzymes.  

PubMed

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

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

2011-01-01

159

EzCatDB: the enzyme reaction database, 2015 update.  

PubMed

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

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

2015-01-28

160

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, Lucía; Peluffo, Gonzalo; Alvarez, María Noel; Martínez, Alejandra

2013-01-01

161

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.

162

Implementing the Workforce Investment Act.  

ERIC Educational Resources Information Center

Describes the Department of Labor's Workforce Investment Act (WIA), which repeals the Job Training Partnership Act. WIA is designed to improve currently fragmented efforts to serve many different needs and purposes and to deliver services to both job seekers and employers. It encourages elected state and local officials to establish new boards…

Johnson, Eric

2000-01-01

163

PETROLEUM INDUSTRY INFORMATION REPORTING ACT  

E-print Network

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

164

Nurse Reinvestment Act. Public Law.  

ERIC Educational Resources Information Center

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

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

165

Advanced Communications Technology Satellite (ACTS)  

Microsoft Academic Search

The authors provide an overview of the NASA Advanced Communications Technology Satellite (ACTS) and discuss the value of the technology for future communication systems. The high-risk technologies selected for ACTS were those having the potential to dramatically enhance the capabilities of the satellite communications industry. This experimental satellite, which is scheduled to be launched in 1992, will furnish very small

R. T. Gedney; R. J. Schertler

1989-01-01

166

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.

167

Proteolytic enzymes of Phymatotrichum omnivorum  

E-print Network

the substrate, and (d) the substrate plus the enzyme solution which had been incubated at 37. 5 C for a period of several hours. The paper chromatograms were developed in one of ac~eral types of solvents (specified in the results) using the ascending method...

Burgum, Alexis August

1964-01-01

168

Enzyme-sensing chitosan hydrogels.  

PubMed

We report on a chitosan hydrogel-based platform for the detection of enzymes, which is compatible with the implementation in infection-sensing wound dressings. Thin films of the established wound dressing biopolymer chitosan were functionalized with a fluorogenic substrate, which is released upon enzymatic degradation, resulting in a pronounced increase in fluorescence emission intensity. In this first model study, the fluorogenic substrate alanyl-alanyl-phenylalanine-7-amido-4-methylcoumarin (AAP-AMC) was covalently conjugated via amide bond formation to chitosan and was shown to facilitate the detection of the serine protease ?-chymotrypsin. Systematic investigations established the dependence of hydrogel thickness and substrate loading on the hydrogel preparation conditions, as well as the dependence of the rate of the reaction on the initial enzyme concentration and the loading of AAP-AMC in the hydrogel. The initial release rate of the fluorophore 7-AMC was found to be linear with enzyme concentration and substrate loading and was independent of hydrogel thickness. Under optimized conditions the hydrogel reports the presence of ?-chymotrypsin in <5 min with a limit of detection of ?10 nM. This generic approach, which can be adapted to detect different kinds of enzymes by using appropriate fluorogenic or chromogenic substrates, is highly interesting for targeting the detection of specific pathogenic bacteria, e.g., in wound dressings. PMID:24914451

Sadat Ebrahimi, Mir Morteza; Schönherr, Holger

2014-07-01

169

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

170

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

171

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

172

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

173

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

174

Effects of Environment on Enzymes  

NSDL National Science Digital Library

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

Ms. Georgia Everett (Tri-Central Community Schools)

2011-04-01

175

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

Code of Federal Regulations, 2011 CFR

...Clean Air Act and the Federal Water Pollution Control Act. 2543.86 Section...Clean Air Act and the Federal Water Pollution Control Act. Contracts...7401 et seq.) and the Federal Water Pollution Control Act as amended (33...

2011-10-01

176

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

Code of Federal Regulations, 2012 CFR

...Clean Air Act and the Federal Water Pollution Control Act. 2543.86 Section...Clean Air Act and the Federal Water Pollution Control Act. Contracts...7401 et seq.) and the Federal Water Pollution Control Act as amended (33...

2012-10-01

177

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

Code of Federal Regulations, 2010 CFR

...Clean Air Act and the Federal Water Pollution Control Act. 2543.86 Section...Clean Air Act and the Federal Water Pollution Control Act. Contracts...7401 et seq.) and the Federal Water Pollution Control Act as amended (33...

2010-10-01

178

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

Code of Federal Regulations, 2013 CFR

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

2013-10-01

179

Acting to let someone die.  

PubMed

This paper examines the recent prominent view in medical ethics that withdrawing life-sustaining treatment (LST) is an act of killing. I trace this view to the rejection of the traditional claim that withdrawing LST is an omission rather than an act. Although that traditional claim is not as problematic as this recent prominent view suggests, my main claim is that even if we accepted that withdrawing LST should be classified as an act rather than as an omission, it could still be classified as letting die rather than killing. Even though omissions are contrasted with acts, letting die need not be, for one can let die by means of acts. The remainder of the paper is devoted to establishing this claim and addresses certain objections to it. PMID:24320715

McGee, Andrew

2015-02-01

180

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 ...

181

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

Microsoft Academic Search

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

WILLIAM J. MACKAY; JANIS M. O'DONNELL

182

Using amphiphilic pseudo amino acid composition to predict enzyme subfamily classes  

Microsoft Academic Search

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

Kuo-chen Chou

2005-01-01

183

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

184

Anaplerotic Role for Cytosolic Malic Enzyme in Engineered Saccharomyces cerevisiae Strains?  

PubMed Central

Malic enzyme catalyzes the reversible oxidative decarboxylation of malate to pyruvate and CO2. The Saccharomyces cerevisiae MAE1 gene encodes a mitochondrial malic enzyme whose proposed physiological roles are related to the oxidative, malate-decarboxylating reaction. Hitherto, the inability of pyruvate carboxylase-negative (Pyc?) S. cerevisiae strains to grow on glucose suggested that Mae1p cannot act as a pyruvate-carboxylating, anaplerotic enzyme. In this study, relocation of malic enzyme to the cytosol and creation of thermodynamically favorable conditions for pyruvate carboxylation by metabolic engineering, process design, and adaptive evolution, enabled malic enzyme to act as the sole anaplerotic enzyme in S. cerevisiae. The Escherichia coli NADH-dependent sfcA malic enzyme was expressed in a Pyc? S. cerevisiae background. When PDC2, a transcriptional regulator of pyruvate decarboxylase genes, was deleted to increase intracellular pyruvate levels and cells were grown under a CO2 atmosphere to favor carboxylation, adaptive evolution yielded a strain that grew on glucose (specific growth rate, 0.06 ± 0.01 h?1). Growth of the evolved strain was enabled by a single point mutation (Asp336Gly) that switched the cofactor preference of E. coli malic enzyme from NADH to NADPH. Consistently, cytosolic relocalization of the native Mae1p, which can use both NADH and NADPH, in a pyc1,2? pdc2? strain grown under a CO2 atmosphere, also enabled slow-growth on glucose. Although growth rates of these strains are still low, the higher ATP efficiency of carboxylation via malic enzyme, compared to the pyruvate carboxylase pathway, may contribute to metabolic engineering of S. cerevisiae for anaerobic, high-yield C4-dicarboxylic acid production. PMID:21131518

Zelle, Rintze M.; Harrison, Jacob C.; Pronk, Jack T.; van Maris, Antonius J. A.

2011-01-01

185

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

186

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

187

Enzyme dynamics from NMR spectroscopy.  

PubMed

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

Palmer, Arthur G

2015-02-17

188

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

189

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

190

Single-molecule enzyme kinetics in the presence of inhibitors  

NASA Astrophysics Data System (ADS)

Recent studies in single-molecule enzyme kinetics reveal that the turnover statistics of a single enzyme is governed by the waiting time distribution that decays as mono-exponential at low substrate concentration and multi-exponential at high substrate concentration. The multi-exponentiality arises due to protein conformational fluctuations, which act on the time scale longer than or comparable to the catalytic reaction step, thereby inducing temporal fluctuations in the catalytic rate resulting in dynamic disorder. In this work, we study the turnover statistics of a single enzyme in the presence of inhibitors to show that the multi-exponentiality in the waiting time distribution can arise even when protein conformational fluctuations do not influence the catalytic rate. From the Michaelis-Menten mechanism of inhibited enzymes, we derive exact expressions for the waiting time distribution for competitive, uncompetitive, and mixed inhibitions to quantitatively show that the presence of inhibitors can induce dynamic disorder in all three modes of inhibitions resulting in temporal fluctuations in the reaction rate. In the presence of inhibitors, dynamic disorder arises due to transitions between active and inhibited states of enzymes, which occur on time scale longer than or comparable to the catalytic step. In this limit, the randomness parameter (dimensionless variance) is greater than unity indicating the presence of dynamic disorder in all three modes of inhibitions. In the opposite limit, when the time scale of the catalytic step is longer than the time scale of transitions between active and inhibited enzymatic states, the randomness parameter is unity, implying no dynamic disorder in the reaction pathway.

Saha, Soma; Sinha, Antara; Dua, Arti

2012-07-01

191

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

192

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

193

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

194

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

195

Food Quality Protection Act (FQPA)  

NSDL National Science Digital Library

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

2008-12-08

196

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...

197

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

198

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

199

Stress-Induced Enzyme Compounds Methamphetamine Neurotoxicity  

MedlinePLUS

... They implicate ketoprofen’s main target, the pro-inflammatory enzyme cyclooxygenase (COX-1/COX-2), in the stress- ... citation National Institute on Drug Abuse. Stress-Induced Enzyme Compounds Methamphetamine Neurotoxicity Retrieved from http://www.drugabuse. ...

200

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

PubMed

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

Golicnik, Marko

2002-01-01

201

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

202

Purification and characterization of carbon-phosphorus bond-cleavage enzyme from glyphosate degrading Pseudomonas putida T5.  

PubMed

An inducible, carbon-phosphorus bond-cleavage enzyme was purified from cells of Pseudomonas putida T5 grown on N-phosphonomethyl glycine. The native enzyme had a molecular mass of approximately 70 kD and upon sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), yielded a homogeneous protein band with an apparent molecular mass of about 70 kD. Activity of purified enzyme was increased by 627-fold compared to the crude extract and showed pH and temperature optima of approximately 7 and 30°C, respectively. The purified enzyme had an apparent Km and Vmax of 3.7 mM and 6.8 mM/min, respectively, for its sole substrate N-phosphonomethyl glycine. The enzyme was inhibited by phenylmethylsulfonyl fluoride (PMSF), indicating the presence of serine at the active site. The enzyme was not inhibited by SDS, suggesting the absence of disulfide linkage in the enzyme. The enzyme was found to be inhibited by most of the metals studied except Mg(2+). Detergents studied also inhibited glyphosate acting as a carbon-phosphorus bond-cleavage enzyme. Thus initial characterization of the purified enzyme suggested that it could be used as a potential candidate for glyphosate bioremediation. PMID:24840030

Selvi, A Arul; Manonmani, H K

2015-01-01

203

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

204

Designing artificial enzymes by intuition and computation  

Microsoft Academic Search

The rational design of artificial enzymes, either by applying physico-chemical intuition of protein structure and function or with the aid of computational methods, is a promising area of research with the potential to tremendously impact medicine, industrial chemistry and energy production. Designed proteins also provide a powerful platform for dissecting enzyme mechanisms of natural systems. Artificial enzymes have come a

Vikas Nanda; Ronald L. Koder

2010-01-01

205

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

206

Clostridial hydrolytic enzymes degrading extracellular components  

Microsoft Academic Search

Bacteria belonging to the genus Clostridium, both glycolytic and proteolytic, and both pathogenic and non-pathogenic, produce a battery of hydrolytic enzymes to obtain nutrients from various biopolymers. The clostridial hydrolytic enzymes are diverse, and are used or are potentially useful for fundamental and applied research purposes. Among them, enzymes degrading the major components in the extracellular matrix or on the

Osamu Matsushita; Akinobu Okabe

2001-01-01

207

HOG CHOLERA VIRUS : SENSITIVITY TO HYDROLYTIC ENZYMES *  

E-print Network

HOG CHOLERA VIRUS : SENSITIVITY TO HYDROLYTIC ENZYMES * H. LAUDE Institut National de la Recherche in greater detail the behavior of the HCV towards two hydrolytic enzymes, trypsin and phospholipase C THIVERVAL GRIGNON, France Résumé VIRUS DE LA PESTE PORCINE CLASSIQUE : SENSIBILITE AUX ENZYMES HYDROLYTIQUES

Paris-Sud XI, Université de

208

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

209

Determining Enzyme Activity by Radial Diffusion  

ERIC Educational Resources Information Center

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

Davis, Bill D.

1977-01-01

210

Restricting SBH Ambiguity via Restriction Enzymes  

E-print Network

Restricting SBH Ambiguity via Restriction Enzymes Steven Skiena1 and Sagi Snir2 1 Department, we build on [20] to enhance the resolving power of restriction enzymes. We give a hardness result­417, 2002. c Springer-Verlag Berlin Heidelberg 2002 #12;Restricting SBH Ambiguity via Restriction Enzymes

Snir, Sagi

211

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

212

Better Enzymes for Biofuels and Green Chemistry  

E-print Network

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

213

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

214

A Structural Perspective on Enzymes Activated by  

E-print Network

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

Di Cera, Enrico

215

Structure-Function Relationships of Glucansucrase and Fructansucrase Enzymes from Lactic Acid Bacteria  

PubMed Central

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 ?-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 ?-amylase enzymes (family GH13), with a predicted permuted (?/?)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 ?-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 ?-fructan polymers with either ?-(2?6) (inulin) or ?-(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 ?-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 ?-(2?6) or ?-(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.

2006-01-01

216

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

217

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

Microsoft Academic Search

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

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

1997-01-01

218

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

219

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

220

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.

221

Finding Sequences for over 270 Orphan Enzymes  

PubMed Central

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

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

2014-01-01

222

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

223

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

224

Uroporphyrinogen decarboxylation as a benchmark for the catalytic proficiency of enzymes  

PubMed Central

The magnitude of an enzyme's affinity for the altered substrate in the transition state exceeds its affinity for the substrate in the ground state by a factor matching the rate enhancement that the enzyme produces. Particularly remarkable are those enzymes that act as simple protein catalysts, without the assistance of metals or other cofactors. To determine the extent to which one such enzyme, human uroporphyrinogen decarboxylase, enhances the rate of substrate decarboxylation, we examined the rate of spontaneous decarboxylation of pyrrolyl-3-acetate. Extrapolation of first-order rate constants measured at elevated temperatures indicates that this reaction proceeds with a half-life of 2.3 × 109 years at 25 °C in the absence of enzyme. This enzyme shows no significant homology with orotidine 5?-monophosphate decarboxylase (ODCase), another cofactorless enzyme that catalyzes a very slow reaction. It is proposed that, in both cases, a protonated basic residue (Arg-37 in the case of human UroD; Lys-93 in the case of yeast ODCase) furnishes a counterion that helps the scissile carboxylate group of the substrate leave water and enter a relatively nonpolar environment, stabilizes the incipient carbanion generated by the departure of CO2, and supplies the proton that takes its place. PMID:18988736

Lewis, Charles A.; Wolfenden, Richard

2008-01-01

225

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

226

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

227

3D imaging of enzymes working in situ.  

PubMed

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

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

2014-06-01

228

7 CFR 983.2 - Act.  

Code of Federal Regulations, 2011 CFR

...AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE PISTACHIOS GROWN IN CALIFORNIA, ARIZONA, AND NEW MEXICO Definitions § 983.2 Act. Act means Public Act No. 10, 73rd...

2011-01-01

229

7 CFR 983.2 - Act.  

Code of Federal Regulations, 2013 CFR

...AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE PISTACHIOS GROWN IN CALIFORNIA, ARIZONA, AND NEW MEXICO Definitions § 983.2 Act. Act means Public Act No. 10, 73rd...

2013-01-01

230

7 CFR 983.2 - Act.  

Code of Federal Regulations, 2010 CFR

...AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE PISTACHIOS GROWN IN CALIFORNIA, ARIZONA, AND NEW MEXICO Definitions § 983.2 Act. Act means Public Act No. 10, 73rd...

2010-01-01

231

7 CFR 983.2 - Act.  

Code of Federal Regulations, 2012 CFR

...AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE PISTACHIOS GROWN IN CALIFORNIA, ARIZONA, AND NEW MEXICO Definitions § 983.2 Act. Act means Public Act No. 10, 73rd...

2012-01-01

232

7 CFR 983.2 - Act.  

Code of Federal Regulations, 2014 CFR

...AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE PISTACHIOS GROWN IN CALIFORNIA, ARIZONA, AND NEW MEXICO Definitions § 983.2 Act. Act means Public Act No. 10,...

2014-01-01

233

75 FR 44852 - Community Reinvestment Act Sunshine  

Federal Register 2010, 2011, 2012, 2013, 2014

...Office of Thrift Supervision Community Reinvestment Act Sunshine...collection. Title of Proposal: Community Reinvestment Act Sunshine...are in fulfillment of the Community Reinvestment Act of 1977 to...and the appropriate Federal banking agencies. This section...

2010-07-29

234

3 CFR - The Endangered Species Act  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

235

7 CFR 926.2 - Act.  

Code of Federal Regulations, 2011 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,...

2011-01-01

236

7 CFR 926.2 - Act.  

Code of Federal Regulations, 2013 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,...

2013-01-01

237

7 CFR 926.2 - Act.  

Code of Federal Regulations, 2012 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,...

2012-01-01

238

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

239

7 CFR 926.2 - Act.  

Code of Federal Regulations, 2014 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,...

2014-01-01

240

7 CFR 906.2 - Act.  

Code of Federal Regulations, 2014 CFR

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

2014-01-01

241

7 CFR 945.2 - Act.  

Code of Federal Regulations, 2012 CFR

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

2012-01-01

242

7 CFR 945.2 - Act.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

243

7 CFR 1230.601 - Act.  

Code of Federal Regulations, 2012 CFR

...ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PORK PROMOTION, RESEARCH, AND CONSUMER INFORMATION Procedures...Definitions § 1230.601 Act. The term Act means the Pork Promotion, Research, and Consumer Information Act of 1985...

2012-01-01

244

7 CFR 1230.601 - Act.  

Code of Federal Regulations, 2011 CFR

...ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PORK PROMOTION, RESEARCH, AND CONSUMER INFORMATION Procedures...Definitions § 1230.601 Act. The term Act means the Pork Promotion, Research, and Consumer Information Act of 1985...

2011-01-01

245

7 CFR 932.2 - Act.  

Code of Federal Regulations, 2013 CFR

... AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE OLIVES GROWN IN CALIFORNIA Order Regulating Handling Definitions § 932.2 Act. Act means Public Act No. 10, 73d...

2013-01-01

246

7 CFR 932.2 - Act.  

Code of Federal Regulations, 2010 CFR

... AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE OLIVES GROWN IN CALIFORNIA Order Regulating Handling Definitions § 932.2 Act. Act means Public Act No. 10, 73d...

2010-01-01

247

7 CFR 932.2 - Act.  

Code of Federal Regulations, 2014 CFR

... AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE OLIVES GROWN IN CALIFORNIA Order Regulating Handling Definitions § 932.2 Act. Act means Public Act No. 10, 73d...

2014-01-01

248

7 CFR 932.2 - Act.  

Code of Federal Regulations, 2012 CFR

... AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE OLIVES GROWN IN CALIFORNIA Order Regulating Handling Definitions § 932.2 Act. Act means Public Act No. 10, 73d...

2012-01-01

249

7 CFR 932.2 - Act.  

Code of Federal Regulations, 2011 CFR

... AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE OLIVES GROWN IN CALIFORNIA Order Regulating Handling Definitions § 932.2 Act. Act means Public Act No. 10, 73d...

2011-01-01

250

7 CFR 1150.101 - Act.  

Code of Federal Regulations, 2010 CFR

...DEPARTMENT OF AGRICULTURE DAIRY PROMOTION PROGRAM Dairy Promotion and Research Order Definitions § 1150.101 Act. Act means Title I, Subtitle B, of the Dairy and Tobacco Adjustment Act of 1983, Pub. L. 98-180, 97 Stat. 1128, as...

2010-01-01

251

7 CFR 1150.101 - Act.  

Code of Federal Regulations, 2011 CFR

...DEPARTMENT OF AGRICULTURE DAIRY PROMOTION PROGRAM Dairy Promotion and Research Order Definitions § 1150.101 Act. Act means Title I, Subtitle B, of the Dairy and Tobacco Adjustment Act of 1983, Pub. L. 98-180, 97 Stat. 1128, as...

2011-01-01

252

7 CFR 930.1 - Act.  

Code of Federal Regulations, 2011 CFR

...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 Public Act No....

2011-01-01

253

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

254

7 CFR 920.2 - Act.  

Code of Federal Regulations, 2011 CFR

...AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE KIWIFRUIT GROWN IN CALIFORNIA Definitions § 920.2 Act. Act means Public Act No. 10, 73d Congress (May 12, 1933),...

2011-01-01

255

7 CFR 920.2 - Act.  

Code of Federal Regulations, 2012 CFR

...AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE KIWIFRUIT GROWN IN CALIFORNIA Definitions § 920.2 Act. Act means Public Act No. 10, 73d Congress (May 12, 1933),...

2012-01-01

256

7 CFR 920.2 - Act.  

Code of Federal Regulations, 2013 CFR

...AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE KIWIFRUIT GROWN IN CALIFORNIA Definitions § 920.2 Act. Act means Public Act No. 10, 73d Congress (May 12, 1933),...

2013-01-01

257

7 CFR 920.2 - Act.  

Code of Federal Regulations, 2014 CFR

...AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE KIWIFRUIT GROWN IN CALIFORNIA Definitions § 920.2 Act. Act means Public Act No. 10, 73d Congress (May 12,...

2014-01-01

258

[Enzyme replacement therapy for hypophosphatasia].  

PubMed

Hypophosphatasia is caused by abnormal tissue-nonspecific alkaline phosphatase (ALP), leading to impaired calcification in bone. Patients with severe hypophosphatasia have difficulties in respiratory function from early days after birth and the rate of lethality is extremely high. Enzyme replacement therapy using bone-targeting recombinant ALP, which has 10 aspartic acids in the C-terminal tail has developed. The efficacy of ERT was firstly observed in model mice of hypophosphatasia. In clinical trial including perinatal and infantile types of hypophosphatasia, efficacy and safety have been reported. Expanded clinical trial is underway and the results of the clinical trial might be reported by the end of the next year. PMID:24473359

Ozono, Keiichi

2014-02-01

259

[Muscle enzyme activity and exercise].  

PubMed

Exercise is classically associated with muscular soreness, presenting one to two days later, delayed onset muscular soreness. Blood muscle enzymes and protein elevations are characteristic, and may cause renal failure. Creatin phosphokinase peak appears on the fourth day and depends on exercise type and individual parameters. This effect is attenuated with repeated bouts, by habituation. Metabolic complications are rare. The knowledge of this reaction, even with common exercises, allows to postpone investigations for a complex metabolic disorder, or to avoid stopping a medication for fear of a side effect, as with statins. Indeed, it is necessary to wait for seven days without any exercise before interpreting an elevated CK result. PMID:19180440

Gojanovic, B; Feihl, F; Gremion, G; Waeber, B

2009-02-01

260

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

261

Memory landscapes of single-enzyme molecules  

NASA Astrophysics Data System (ADS)

Immobilized single horseradish peroxidase enzymes were observed by confocal fluorescence spectroscopy during catalysis of the oxidation reaction of the nonfluorescent dihydrorhodamine 6G substrate into the highly fluorescent product rhodamine 6G. By extracting only the non-Markovian behavior of the spectroscopic two-state process of enzyme-product complex formation and release, memory landscapes were generated for single-enzyme molecules. The memory landscapes can be used to discriminate between different origins of stretched exponential kinetics that are found in the first-order correlation analysis. Memory landscapes of single-enzyme data shows oscillations that are expected in a single-enzyme system that possesses a set of transient states. Alternative origins of the oscillations may not, however, be ruled out. The data and analysis indicate that substrate interaction with the enzyme selects a set of conformational substates for which the enzyme is active.

Edman, Lars; Rigler, Rudolf

2000-07-01

262

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

263

7 CFR 1221.1 - Act.  

Code of Federal Regulations, 2011 CFR

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

2011-01-01

264

7 CFR 1221.1 - Act.  

Code of Federal Regulations, 2012 CFR

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

2012-01-01

265

7 CFR 1221.1 - Act.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

266

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

267

7 CFR 1221.1 - Act.  

Code of Federal Regulations, 2014 CFR

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

2014-01-01

268

7 CFR 1218.1 - Act.  

Code of Federal Regulations, 2010 CFR

...MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE BLUEBERRY PROMOTION, RESEARCH, AND INFORMATION ORDER Blueberry Promotion, Research, and Information Order Definitions § 1218.1 Act. Act...

2010-01-01

269

7 CFR 1214.1 - Act.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

270

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

271

7 CFR 1214.1 - Act.  

Code of Federal Regulations, 2014 CFR

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

2014-01-01

272

7 CFR 1216.1 - Act.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

273

7 CFR 1216.1 - Act.  

Code of Federal Regulations, 2014 CFR

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

2014-01-01

274

7 CFR 1280.101 - Act.  

Code of Federal Regulations, 2010 CFR

...SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE LAMB PROMOTION, RESEARCH, AND INFORMATION ORDER Lamb Promotion, Research, and Information Order Definitions § 1280.101 Act. Act...

2010-01-01

275

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

PubMed

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

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

2015-02-12

276

Long-acting reversible contraception.  

PubMed

Although short-acting reversible hormonal contraceptives, such as oral contraceptives and the contraceptive patch and vaginal ring, remain the most commonly used contraceptive methods in the United States, they are also associated with the highest failure rates. Long-acting reversible contraception (LARC) methods, such as intrauterine devices and contraceptive implants, offer high continuation rates and very low failure rates, and are safe for use in most women. The provision of LARC methods to adolescent, young adult and nulliparous women is a relatively new concept that offers an innovative option for these populations. PMID:24138662

Peck, Susan A

2013-10-01

277

Advanced Communications Technology Satellite (ACTS)  

NASA Technical Reports Server (NTRS)

The NASA Advanced Communications Technology Satellite (ACTS) was conceived to help maintain U.S. leadership in the world's communications-satellite market. This experimental satellite is expected to be launched by NASA in 1992 and to furnish the technology necessary for establishing very small aperture terminal digital networks which provide on-demand full-mesh connectivity, and 1.544-MBPS services with only a single hop. Utilizing on-board switching and processing, each individual voice or data circuit can be separately routed to any location in the network. This paper provides an overview of the ACTS and discusses the value of the technology for future communications systems.

Gedney, Richard T.; Schertler, Ronald J.

1989-01-01

278

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

Code of Federal Regulations, 2014 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...

2014-10-01

279

ACT and General Cognitive Ability  

ERIC Educational Resources Information Center

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

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

2008-01-01

280

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.

281

The Ontogenesis of Speech Acts  

ERIC Educational Resources Information Center

A speech act approach to the transition from pre-linguistic to linguistic communication is adopted in order to consider language in relation to behavior and to allow for an emphasis on the use, rather than the form, of language. A pilot study of mothers and infants is discussed. (Author/RM)

Bruner, Jerome S.

1975-01-01

282

MAJOR PROGRAMS ACTG Acting [BFA  

E-print Network

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

Maryland, Baltimore County, University of

283

Maltose Metabolism in the Hyperthermophilic Archaeon Thermococcus litoralis: Purification and Characterization of Key Enzymes  

PubMed Central

Maltose metabolism was investigated in the hyperthermophilic archaeon Thermococcus litoralis. Maltose was degraded by the concerted action of 4-?-glucanotransferase and maltodextrin phosphorylase (MalP). The first enzyme produced glucose and a series of maltodextrins that could be acted upon by MalP when the chain length of glucose residues was equal or higher than four, to produce glucose-1-phosphate. Phosphoglucomutase activity was also detected in T. litoralis cell extracts. Glucose derived from the action of 4-?-glucanotransferase was subsequently metabolized via an Embden-Meyerhof pathway. The closely related organism Pyrococcus furiosus used a different metabolic strategy in which maltose was cleaved primarily by the action of an ?-glucosidase, a p-nitrophenyl-?-d-glucopyranoside (PNPG)-hydrolyzing enzyme, producing glucose from maltose. A PNPG-hydrolyzing activity was also detected in T. litoralis, but maltose was not a substrate for this enzyme. The two key enzymes in the pathway for maltose catabolism in T. litoralis were purified to homogeneity and characterized; they were constitutively synthesized, although phosphorylase expression was twofold induced by maltodextrins or maltose. The gene encoding MalP was obtained by complementation in Escherichia coli and sequenced (calculated molecular mass, 96,622 Da). The enzyme purified from the organism had a specific activity for maltoheptaose, at the temperature for maximal activity (98°C), of 66 U/mg. A Km of 0.46 mM was determined with heptaose as the substrate at 60°C. The deduced amino acid sequence had a high degree of identity with that of the putative enzyme from the hyperthermophilic archaeon Pyrococcus horikoshii OT3 (66%) and with sequences of the enzymes from the hyperthermophilic bacterium Thermotoga maritima (60%) and Mycobacterium tuberculosis (31%) but not with that of the enzyme from E. coli (13%). The consensus binding site for pyridoxal 5?-phosphate is conserved in the T. litoralis enzyme. PMID:10348846

Xavier, Karina B.; Peist, Ralf; Kossmann, Marina; Boos, Winfried; Santos, Helena

1999-01-01

284

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

PubMed Central

Background In eukaryotic cells the nuclear envelope isolates and protects DNA from molecules that could damage its structure or interfere with its processing. Moreover, selected protection enzymes and vitamins act as efficient guardians against toxic compounds both in the nucleoplasm and in the cytosol. The observation that a cytosolic detoxifying and antioxidant enzyme i.e. glutathione transferase is accumulated in the perinuclear region of the rat hepatocytes suggests that other unrecognized modalities of nuclear protection may exist. Here we show evidence for the existence of a safeguard enzyme machinery formed by an hyper-crowding of cationic enzymes and proteins encompassing the nuclear membrane and promoted by electrostatic interactions. Methodology/Principal Findings Electron spectroscopic imaging, zeta potential measurements, isoelectrofocusing, comet assay and mass spectrometry have been used to characterize this surprising structure that is present in the cells of all rat tissues examined (liver, kidney, heart, lung and brain), and that behaves as a “nuclear shield”. In hepatocytes, this hyper-crowding structure is about 300 nm thick, it is mainly formed by cationic enzymes and the local concentration of key protection enzymes, such as glutathione transferase, catalase and glutathione peroxidase is up to seven times higher than in the cytosol. The catalytic activity of these enzymes, when packed in the shield, is not modified and their relative concentrations vary remarkably in different tissues. Removal of this protective shield renders chromosomes more sensitive to damage by oxidative stress. Specific nuclear proteins anchored to the outer nuclear envelope are likely involved in the shield formation and stabilization. Conclusions/Significance The characterization of this previously unrecognized nuclear shield in different tissues opens a new interesting scenario for physiological and protection processes in eukaryotic cells. Selection and accumulation of protection enzymes near sensitive targets represents a new safeguard modality which deeply differs from the adaptive response which is based on expression of specific enzymes. PMID:21170318

Pallottini, Valentina; Canuti, Lorena; De Canio, Michele; Urbani, Andrea; Marzano, Valeria; Cornetta, Tommaso; Stano, Pasquale; Giovanetti, Anna; Stella, Lorenzo; Canini, Antonella; Federici, Giorgio; Ricci, Giorgio

2010-01-01

285

Functional dynamics of hydrolytic enzymes  

NASA Astrophysics Data System (ADS)

One of important stages of the substrate bond breaking in the active site (AS) of ?-chymotrypsin (ACT) is considered. Three tasks are solved by methods of quantum mechanics and stochastic molecular dynamics: the loosening of peptide bond of a substrate attacked by O- ion of Ser195 of catalytic group; the opportunity of increase of a peptide bond (PB) breaking probability; the increase of this probability related to nonlinear interacting modes (or Fermi resonance (FR)) of oscillations of group N-H in PB. It is shown also that the splitting of vibrational levels Amide A and Amide B in a spectrum of an amide group pays off due to FR.

Kargovsky, Alexey V.; Khodjer, Olga P.; Romanovsky, Yury M.

2003-10-01

286

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

287

Summary of the Clean Water Act  

MedlinePLUS

... enacted in 1948 and was called the Federal Water Pollution Control Act, but the Act was significantly reorganized and expanded in 1972. "Clean Water Act" became the Act's common name with amendments ... pollution control programs such as setting wastewater standards for ...

288

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

289

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

290

Structural Features of the Regulatory ACT Domain of Phenylalanine Hydroxylase  

PubMed Central

Phenylalanine hydroxylase (PAH) catalyzes the conversion of L-Phe to L-Tyr. Defects in PAH activity, caused by mutations in the human gene, result in the autosomal recessively inherited disease hyperphenylalaninemia. PAH activity is regulated by multiple factors, including phosphorylation and ligand binding. In particular, PAH displays positive cooperativity for L-Phe, which is proposed to bind the enzyme on an allosteric site in the N-terminal regulatory domain (RD), also classified as an ACT domain. This domain is found in several proteins and is able to bind amino acids. We used molecular dynamics simulations to obtain dynamical and structural insights into the isolated RD of PAH. Here we show that the principal motions involve conformational changes leading from an initial open to a final closed domain structure. The global intrinsic motions of the RD are correlated with exposure to solvent of a hydrophobic surface, which corresponds to the ligand binding-site of the ACT domain. Our results strongly suggest a relationship between the Phe-binding function and the overall dynamic behaviour of the enzyme. This relationship may be affected by structure-disturbing mutations. To elucidate the functional implications of the mutations, we investigated the structural effects on the dynamics of the human RD PAH induced by six missense hyperphenylalaninemia-causing mutations, namely p.G46S, p.F39C, p.F39L, p.I65S, p.I65T and p.I65V. These studies showed that the alterations in RD hydrophobic interactions induced by missense mutations could affect the functionality of the whole enzyme. PMID:24244510

Carluccio, Carla; Fraternali, Franca; Salvatore, Francesco; Fornili, Arianna; Zagari, Adriana

2013-01-01

291

[Recent advances in enzyme assays using fluoremetry].  

PubMed

Enzymes play such a pivotal role in cellular metabolism that enzyme assays are important for bio-engineering, disease diagnoses and drug discovery. Among the reported methods, fluoremetry has attracted more and more attention due to its high sensitivity and possibility of continuous dynamic monitoring. The recent progresses and applications in enzyme assays using fluorescent probes were reviewed. Different methods were classified into direct fluorescence detection and indirect fluorescence detection according to their labeled substrates and detection mechanisms. Our writing purpose is to provide the readers with a flavor of the kinds of tools and strategies available in enzyme assays with fluorescent probes. Also, the research situation and prospects were disucssed PMID:20352949

Xing, Yanlong; Mao, Xiangzhao; Wang, Shu; Wang, Hualei; Wei, Dongzhi

2009-12-01

292

Designing Artificial Enzymes by Intuition and Computation  

PubMed Central

The rational design of artificial enzymes either by applying physio-chemical intuition of protein structure and function or with the aid of computation methods is a promising area of research with the potential to tremendously impact medicine, industrial chemistry and energy production. Designed proteins also provide a powerful platform for dissecting enzyme mechanisms of natural systems. Artificial enzymes have come a long way, from simple ?-helical peptide catalysts to proteins that facilitate multi-step chemical reactions designed by state-of-the-art computational methods. Looking forward, we examine strategies employed by natural enzymes which could be used to improve the speed and selectivity of artificial catalysts. PMID:21124375

Nanda, Vikas; Koder, Ronald L.

2012-01-01

293

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

294

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

295

Advanced Communications Technology Satellite (ACTS)  

NASA Technical Reports Server (NTRS)

The NASA Advanced Communications Technology Satellite (ACTS) provides high risk technologies having the potential to dramatically enhance the capabilities of the satellite communications industry. This experimental satellite, which will be launched by NASA in 1993, will furnish the technology necessary for providing a range of services. Utilizing the ACTS very-high-gain-hopping spot-beam antennas with on-board routing and processing, Very Small Aperture Terminal (VSAT) digital networks which provide on-demand, full-mesh-convectivity 1.544-MBPS services with only a single hop can be established. The high-gain spot-beam antenna at Ka-band permits wide area, flexible networks providing high data rate services between modest-size earth terminals.

Plecity, Mark S.; Nall, Mark E.

1991-01-01

296

National Park Service: Antiquities Act  

NSDL National Science Digital Library

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

297

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.

298

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

PubMed

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

2013-11-01

299

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

300

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

301

SCADA Application for ACTS Technology  

NASA Technical Reports Server (NTRS)

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

Fairbanks, Barry

1992-01-01

302

Overview of the ACT program  

NASA Technical Reports Server (NTRS)

NASA's Advanced Composites Program (ACT) was initiated in 1988. A National Research Announcement was issued to solicit innovative ideas that could significantly contribute to development and demonstration of an integrated technology data base and confidence level that permits cost-effective use of composite primary structures in transport aircraft. Fifteen contracts were awarded by the Spring of 1989 and the participants include commercial and military airframe manufacturers, materials developers and suppliers, universities, and government laboratories. The program approach is to develop materials, structural mechanics methodology, design concepts, and fabrication procedures that offer the potential to make composite structures cost-effective compared to aluminum structure. Goals for the ACT program included 30-50 percent weight reduction, 20-25 percent acquisition cost reduction, and provided the scientific basis for predicting materials and structures performance. This paper provides an overview of the ACT program status, plans, and selected technical accomplishments. Sixteen additional papers, which provide more detailed information on the research and development accomplishments, are contained in this publication.

Davis, John G., Jr.

1992-01-01

303

Phase II enzymes and bioactivation.  

PubMed

A colloquium entitled Phase II enzymes and bioactivation was held during the 10th International Symposium on Microsomes and Drug Oxidations in Toronto, Ont., on July 20, 1994. This colloquium was a tribute in recognition of the contributions by Dr. James R. Gillette in advancing our understanding of drug metabolism and chemical toxicity. A major focus of the colloquium was formation of conjugates such as those with glutathione (GSH) that may not lead to detoxification but to bioactivation. The GSH conjugates may be further metabolized to reactive species that cause toxicity. The nephrotoxicity of hydroquinone and bromobenzene is mediated via quinone - glutathione conjugates, and is manifested in cellular changes, including induction of the gadd-153 and hsp-70 mRNA. The formation of GSH conjugates is also involved in the bioactivation of the vicinal dihalopropane 1,2-dibromo-3-chloropropane; cytotoxic lesions are observed in the kidney and testes The evidence indicates that conjugation is mediated by the GSH S-transferases. The symposium also covered aspects of the importance of conjugation in the pharmacokinetics of certain drugs. Conjugation reactions including sulfation are markedly influenced by the manner in which the liver processes the drug. Characteristics such as erythrocyte binding, as in the case of acetaminophen, become limiting factors in the conjugation reactions. Conjugation reactions can lead to a different outcome, such as acquired drug resistance. Conjugation of metallothioneins with the alkylating mustard drugs melphalan and chlorambucil can lead to the formation of protein adducts. Conjugation of reactive intermediates with these small molecular weight proteins may be considered as a phase II reaction and a mechanism of detoxification. A different pathway for the metabolism of xenobiotics is catalyzed by the carboxylesterases, a family of enzymes that is involved in hydrolysis of chemical compounds, generally leading to detoxification. Three rat esterases have been purified, cloned, and characterized. Two forms, hydrolase A and hydrolase B, are present in liver microsomes in a number of species, including the human. These are also detected in extrahepatic tissues. A third esterase, hydrolase S, is found in rat liver microsomes and rat serum, and may be a serum carboxylesterase secreted from the liver. A better knowledge of esterases will advance our understanding of pharmacokinetics and mechanisms of the effects of chemicals such as phenacetin and acetaminophen, two drugs that Dr. Gillette has worked with extensively. The data presented herein reflect the new and innovative approaches that have been adopted to investigate various aspects of chemical toxicity and drug metabolism. These data also indicate that significant insights are likely to come from integrated approaches utilizing established toxicological techniques together with those from other disciplines, including molecular biology and analytical chemistry. PMID:8748931

Hinson, J A; Forkert, P G

1995-10-01

304

The Mental Health Act and the Mental Capacity Act: untangling the relationship  

Microsoft Academic Search

The Mental Health Act (1983) and the Mental Capacity Act (2005) (both amended by the Mental Health Act (2007)) together provide a comprehensive framework for the care and treatment of people with a mental disorder in England and Wales. The Mental Health Act relates solely to the treatment of mental disorders whilst the Mental Capacity Act has much wider applicability

Daniel P. Herlihy; Frank Holloway

2009-01-01

305

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

E-print Network

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

306

Estuary Restoration Act of 2000 Title I of Estuaries and Clean Waters Act of 2000  

E-print Network

Estuary Restoration Act of 2000 Title I of Estuaries and Clean Waters Act of 2000 Public Law 106 of the Estuary Restoration Act, Title I of P.L. 106-457 (Act). The contents reflect the views of the Estuary). Background: The purposes of the Act are to promote the restoration of estuary habitat; develop a national

US Army Corps of Engineers

307

Dietary conjugated linoleic acid induces peroxisome-specific enzyme accumulation and ornithine decarboxylase activity in mouse liver  

Microsoft Academic Search

Previous studies have shown that the dietary fatty acids, conjugated linoleic acids (CLA), inhibit carcinogenesis in the colon, mammary gland, forestomach, and skin. Several properties of this chemoprotective polyunsaturated fatty acid suggest it will act as an hepatic peroxisome proliferator. This study evaluated the effect of dietary CLA on the accumulation of enzymes associated with peroxisome proliferation in rodent liver.

Martha A. Belury; Silvia Y. Moya-Camarena; Kai-Li Liu; John P. Vanden Heuvel

1997-01-01

308

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.

309

Enzyme activity assay of glycoprotein enzymes based on a boronate affinity molecularly imprinted 96-well microplate.  

PubMed

Enzyme activity assay is an important method in clinical diagnostics. However, conventional enzyme activity assay suffers from apparent interference from the sample matrix. Herein, we present a new format of enzyme activity assay that can effectively eliminate the effects of the sample matrix. The key is a 96-well microplate modified with molecularly imprinted polymer (MIP) prepared according to a newly proposed method called boronate affinity-based oriented surface imprinting. Alkaline phosphatase (ALP), a glycoprotein enzyme that has been routinely used as an indicator for several diseases in clinical tests, was taken as a representative target enzyme. The prepared MIP exhibited strong affinity toward the template enzyme (with a dissociation constant of 10(-10) M) as well as superb tolerance for interference. Thus, the enzyme molecules in a complicated sample matrix could be specifically captured and cleaned up for enzyme activity assay, which eliminated the interference from the sample matrix. On the other hand, because the boronate affinity MIP could well retain the enzymatic activity of glycoprotein enzymes, the enzyme captured by the MIP was directly used for activity assay. Thus, additional assay time and possible enzyme or activity loss due to an enzyme release step required by other methods were avoided. Assay of ALP in human serum was successfully demonstrated, suggesting a promising prospect of the proposed method in real-world applications. PMID:25405946

Bi, Xiaodong; Liu, Zhen

2014-12-16

310

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...

311

Imaging of enzyme replacement therapy using PET  

PubMed Central

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

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

2010-01-01

312

Characterization of Soil Samples of Enzyme Activity  

ERIC Educational Resources Information Center

Described are nine enzyme essays for distinguishing soil samples. Colorimetric methods are used to compare enzyme levels in soils from different sites. Each soil tested had its own spectrum of activity. Attention is drawn to applications of this technique in forensic science and in studies of soil fertility. (Author/AJ)

Freeland, P. W.

1977-01-01

313

Enzymes: A Workshop for Secondary School Students.  

ERIC Educational Resources Information Center

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

Bering, C. Larry

1994-01-01

314

Enzyme-catalyzed polymerization to functional polymers  

Microsoft Academic Search

In this article, described are our recent advances in enzymatic polymerization, defined as chemical polymer syntheses in vitro (in test tubes) via non-biosynthetic pathways catalyzed by an isolated enzyme. The major target macromolecules formed via the enzymatic polymerizations in this article are polyesters and polyphenols. For synthesis of polyesters, hydrolases are used as catalyst; hydrolases, enzymes catalyzing a bond-cleavage reaction

Hiroshi Uyama; Shiro Kobayashi

2002-01-01

315

MODEL FOR ENZYME KINETICS USING PETRI NETWORKS  

Microsoft Academic Search

In this paper we propose a model for single substrate enzyme kinetics based on the differential Petri network formalism. Metabolic signaling pathways imply biochemical reactions in which substrates are enzyme catalyzed and turn them into active biochemical products. The enzymatic reactions are described quantitatively through ordinary differential equations (ODEs) in the proposed Petri network model. The specificity of the biochemical

RADU DOBRESCU; A. POPA; VICTOR PURCAREA

2009-01-01

316

Improving enzymes for cancer gene therapy  

Microsoft Academic Search

New techniques now make it feasible to tailor enzymes for cancer gene therapy. Novel enzymes with desired properties can be created and selected from vast libraries of mutants containing random substitutions within catalytic domains. In this review, we first consider genes for the ablation of tumors, namely, genes that have been mutated (or potentially can be mutated) to afford enhanced

Lance P. Encell; Daniel M. Landis; Lawrence A. Loeb

1999-01-01

317

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

318

Restriction Enzyme Mapping: A Simple Student Practical.  

ERIC Educational Resources Information Center

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

Higgins, Stephen J.; And Others

1990-01-01

319

Entrapping Enzyme in a Functionalized Nanoporous Support  

Microsoft Academic Search

The enzyme organophosphorus hydrolase (OPH) was spontaneously entrapped in carboxylethyl- or aminopropyl-functionalized mesoporous silica with rigid, uniform open-pore geometry (30 nm). This approach yielded larger amounts of protein loading and much higher specific activity of the enzyme when compared to the unfunctionalized mesoporous silica and normal porous silica with the same pore size. When OPH was incubated with the functionalized

Chenghong Lei; Yongsoon Shin; Jun Liu; Eric J. Ackerman

2002-01-01

320

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

321

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

322

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. PMID:25346733

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

2014-01-01

323

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

324

Substrate analogues for isoprenoid enzymes  

SciTech Connect

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

Stremler, K.E.

1987-01-01

325

Tyrosinase immobilized enzyme reactor: development and evaluation.  

PubMed

Immobilized enzyme reactors of tyrosinase (tyr-IMERs) for use on-line in HPLC system were prepared by different procedures and then compared. The enzyme, obtained from Agaricus bisporus, was immobilized on epoxy-silica which was prepared using different conditions. Enzyme immobilization was conducted by both in situ and in batch techniques. The different procedures were compared in terms of protein and activity retention, IMERs activity, kinetics and stability. The influence of immobilization procedure on enzyme activity and the behavior of the IMERs against a standard inhibitor were also investigated. In situ immobilization on epoxy-silica, synthesized using microwave assistance, provided the best conditions to prepare tyrosinase IMERs. The tyr-IMERs were successfully tested with known and potential inhibitors of tyrosinase, and the results showed that they can be used for the screening of inhibitors of that enzyme. PMID:24317418

de Oliveira, Karina Bora; Mischiatti, Keylla Lençone; Fontana, José Domingos; de Oliveira, Brás Heleno

2014-01-15

326

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

327

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

328

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

329

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

330

Acts related to solid waste management in Illinois. Annual report  

SciTech Connect

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

Not Available

1994-04-01

331

Structural genomics of enzymes involved in sterol/isoprenoid biosynthesis  

PubMed Central

X-ray structures of two enzymes in the sterol/isoprenoid biosynthesis pathway have been determined in a structural genomics pilot study. Mevalonate-5-diphosphate decarboxylase (MDD) is a single-domain ?/? protein that catalyzes the last of three sequential ATP-dependent reactions which convert mevalonate to isopentenyl diphosphate. Isopentenyl disphosphate isomerase (IDI) is an ?/? metalloenzyme that catalyzes interconversion of isopentenyl diphosphate and dimethylallyl diphosphate, which condense in the next step toward synthesis of sterols and a host of natural products. Homology modeling of related proteins and comparisons of the MDD and IDI structures with two other experimentally determined structures have shown that MDD is a member of the GHMP superfamily of small-molecule kinases and IDI is similar to the nudix hydrolases, which act on nucleotide diphosphatecontaining substrates. Structural models were produced for 379 proteins, encompassing a substantial fraction of both protein superfamilies. All three enzymes responsible for synthesis of isopentenyl diphosphate from mevalonate (mevalonate kinase, phosphomevalonate kinase, and MDD) share the same fold, catalyze phosphorylation of chemically similar substrates (MDD decarboxylation involves phosphorylation of mevalonate diphosphate), and seem to have evolved from a common ancestor. These structures and the structural models derived from them provide a framework for interpreting biochemical function and evolutionary relationships. PMID:11698677

Bonanno, Jeffrey B.; Edo, Carme; Eswar, Narayanan; Pieper, Ursula; Romanowski, Michael J.; Ilyin, Valentin; Gerchman, Sue Ellen; Kycia, Helen; Studier, F. William; Sali, Andrej; Burley, Stephen K.

2001-01-01

332

Fast-acting valve actuator  

DOEpatents

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

Cho, Nakwon (Knoxville, TN)

1980-01-01

333

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

334

78 FR 36279 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013, 2014

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

2013-06-17

335

Family and Medical Leave Act (FMLA)  

MedlinePLUS

... Medical Leave Act of 1993 (FMLA) in light of the United States Supreme Court’s decision in United States v. Windsor, which found section 3 of the Defense of Marriage Act (DOMA) to be unconstitutional. ...

336

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

337

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

338

7 CFR 65.100 - Act.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

339

7 CFR 65.100 - Act.  

Code of Federal Regulations, 2014 CFR

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

2014-01-01

340

7 CFR 65.100 - Act.  

Code of Federal Regulations, 2011 CFR

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

2011-01-01

341

7 CFR 65.100 - Act.  

Code of Federal Regulations, 2012 CFR

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

2012-01-01

342

7 CFR 1230.1 - Act.  

Code of Federal Regulations, 2013 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE PORK PROMOTION, RESEARCH, AND CONSUMER INFORMATION Pork Promotion, Research, and Consumer Information...Definitions § 1230.1 Act. Act means the Pork Promotion, Research, and Consumer...

2013-01-01

343

7 CFR 1230.1 - Act.  

Code of Federal Regulations, 2010 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE PORK PROMOTION, RESEARCH, AND CONSUMER INFORMATION Pork Promotion, Research, and Consumer Information...Definitions § 1230.1 Act. Act means the Pork Promotion, Research, and Consumer...

2010-01-01

344

7 CFR 1230.1 - Act.  

Code of Federal Regulations, 2014 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE PORK PROMOTION, RESEARCH, AND CONSUMER INFORMATION Pork Promotion, Research, and Consumer Information...Definitions § 1230.1 Act. Act means the Pork Promotion, Research, and Consumer...

2014-01-01

345

7 CFR 1230.1 - Act.  

Code of Federal Regulations, 2012 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE PORK PROMOTION, RESEARCH, AND CONSUMER INFORMATION Pork Promotion, Research, and Consumer Information...Definitions § 1230.1 Act. Act means the Pork Promotion, Research, and Consumer...

2012-01-01

346

7 CFR 1230.1 - Act.  

Code of Federal Regulations, 2011 CFR

...COMMODITIES), DEPARTMENT OF AGRICULTURE PORK PROMOTION, RESEARCH, AND CONSUMER INFORMATION Pork Promotion, Research, and Consumer Information...Definitions § 1230.1 Act. Act means the Pork Promotion, Research, and Consumer...

2011-01-01

347

Mental Health Parity and Addiction Equity Act  

MedlinePLUS

... Engagement Training Resources The Mental Health Parity and Addiction Equity Act Contents Introduction Summary of MHPAEA Protections ... Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act of 2008 (MHPAEA) is a federal ...

348

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

349

Regulation of enzyme levels in the blood. Influence of environmental and genetic factors on enzyme clearance.  

PubMed Central

Since its discovery, lactic dehydrogenase virus (LDV) has remained unique as a model of long-term enzyme elevation due to impairment of enzyme clearance. The present study shows that mice inoculated with silica develop an increase in plasma lactate dehydrogenase (LDH) lasting for at least 6 months and that the enzyme elevation is due, at least in part, to impairment of clearance. The extent of the enzyme elevation is dependent on both the dose and route of silica administration and mice that had received both silica and LDV showed a more profound impairment of LDH clearance than mice that had received silica or LDV alone. Examination of the factors that regulate circulating enzyme levels in normal mice revealed that whereas there was no difference in resting enzyme levels among several inbred strains of mice (BALB/cAnN, NZBWF1/J,B10.D2/nSnN, and A/J mice), when mice were stressed by the administration of an enzyme load, certain inbred strains (BALB/cAnN) cleared the enzyme rapidly and others (B10.D2/nSnN) cleared the enzyme slowly. Moreover, in B10.D2/nSnN mice, enzyme clearance was age-related. When different strains of mice were infected with LDV, LDH levels were substantially higher in the circulation of slow enzyme clearers as compared to rapid enzyme clearers. It is concluded that both environmental and genetic factors influence the clearance of LDH and that impairment of enzyme clearance may be a more important factor than previously suspected in regulating enzyme levels in disease states. PMID:2843049

Hayashi, T.; Salata, K.; Kingman, A.; Notkins, A. L.

1988-01-01

350

Expression of lignocellulolytic enzymes in Pichia pastoris  

PubMed Central

Background Sustainable utilization of plant biomass as renewable source for fuels and chemical building blocks requires a complex mixture of diverse enzymes, including hydrolases which comprise the largest class of lignocellulolytic enzymes. These enzymes need to be available in large amounts at a low price to allow sustainable and economic biotechnological processes. Over the past years Pichia pastoris has become an attractive host for the cost-efficient production and engineering of heterologous (eukaryotic) proteins due to several advantages. Results In this paper codon optimized genes and synthetic alcohol oxidase 1 promoter variants were used to generate Pichia pastoris strains which individually expressed cellobiohydrolase 1, cellobiohydrolase 2 and beta-mannanase from Trichoderma reesei and xylanase A from Thermomyces lanuginosus. For three of these enzymes we could develop strains capable of secreting gram quantities of enzyme per liter in fed-batch cultivations. Additionally, we compared our achieved yields of secreted enzymes and the corresponding activities to literature data. Conclusion In our experiments we could clearly show the importance of gene optimization and strain characterization for successfully improving secretion levels. We also present a basic guideline how to correctly interpret the interplay of promoter strength and gene dosage for a successful improvement of the secretory production of lignocellulolytic enzymes in Pichia pastoris. PMID:22583625

2012-01-01

351

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

352

Biochemical enzyme analysis in acute leukaemia.  

PubMed Central

This report summarises the current knowledge regarding the clinical utility of biochemical enzyme markers for both diagnostic and therapeutic purposes in acute leukaemia. The enzymes studied most extensively in this field are terminal deoxynucleotidyl transferase, adenosine deaminase, 5'-nucleotidase, purine nucleoside phosphorylase, and acid phosphatase, esterase, hexosaminidase isoenzymes. For each enzyme, the quantitative and qualitative characteristics in various immunologically defined subclasses of acute leukaemia are described. The quantitative evaluation of enzyme activities represents an adjunctive classification technique which should be incorporated into the multivariate analysis, the "multiple marker analysis." By qualitative characterisation pronounced heterogeneity of leukaemia subsets is uncovered. The application of 2'-deoxycoformycin, a specific inhibitor of adenosine deaminase, and the potential usefulness of two other enzymes as targets for treatment with selective agents is discussed. The concept that gene products expressed at certain developmental stages of normal cells can similarly be detected in leukaemic cells (which therefore seem to be "frozen" or "arrested" at this particular maturation/differentiation stage) is supported by the results obtained in enzyme studies. Besides their practical clinical importance for classification and treatment of acute leukaemias, biochemical enzyme markers constitute a valuable research tool to disclose biological properties of leukaemic cells. PMID:2981904

Drexler, H G; Gaedicke, G; Minowada, J

1985-01-01

353

Transient model of thermal deactivation of enzymes  

PubMed Central

The kinetics of enzyme deactivation provide useful insights on processes that determine the level of biological function of any enzyme. Photinus pyralis (firefly) luciferase is a convenient enzyme system for studying mechanisms and kinetics of enzyme deactivation, refolding, and denaturation caused by various external factors, physical or chemical by nature. In this report we present a study of luciferase deactivation caused by increased temperature (i.e., thermal deactivation). We found that deactivation occurs through a reversible intermediate state and can be described by a Transient model that includes active and reversibly inactive states. The model can be used as a general framework for analysis of complex, multiexponential transient kinetics that can be observed for some enzymes by reaction progression assays. In this study the Transient model has been used to develop an analytical model for studying a time course of luciferase deactivation. The model might be applicable toward enzymes in general and can be used to determine if the enzyme exposed to external factors, physical or chemical by nature, undergoes structural transformation consistent with thermal mechanisms of deactivation. PMID:21749935

Gregory, Kalvin; Sun, Ye; Golovlev, Val

2011-01-01

354

Transient model of thermal deactivation of enzymes.  

PubMed

The kinetics of enzyme deactivation provide useful insights on processes that determine the level of biological function of any enzyme. Photinus pyralis (firefly) luciferase is a convenient enzyme system for studying mechanisms and kinetics of enzyme deactivation, refolding, and denaturation caused by various external factors, physical or chemical by nature. In this report we present a study of luciferase deactivation caused by increased temperature (i.e., thermal deactivation). We found that deactivation occurs through a reversible intermediate state and can be described by a Transient model that includes active and reversibly inactive states. The model can be used as a general framework for analysis of complex, multiexponential transient kinetics that can be observed for some enzymes by reaction progression assays. In this study the Transient model has been used to develop an analytical model for studying a time course of luciferase deactivation. The model might be applicable toward enzymes in general and can be used to determine if the enzyme exposed to external factors, physical or chemical by nature, undergoes structural transformation consistent with thermal mechanisms of deactivation. PMID:21749935

Chen, Nelson G; Gregory, Kalvin; Sun, Ye; Golovlev, Val

2011-10-01

355

The New Jersey Family Leave Act  

E-print Network

The New Jersey Family Leave Act The New Jersey Family Leave Act (N.J.S.A. 34:11B-1, et seq.NJCivilRights.gov The New Jersey mily Leave Act w Jersey Family Leave Act (N.J.S.A. 34:11B-1, et seq.) requires. Pennsylvania Avenue, 3 rd Floor Atlantic City, NJ 08401 (609) 441-3100 (Phone) (609) 441-7648 (TTY) Jersey City

Liu, Alice Y.C.

356

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

357

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

358

MEMORANDUM FOR THE FIELD CLEAN WATER ACT  

E-print Network

MEMORANDUM FOR THE FIELD CLEAN WATER ACT SECTION 404 REGULATORY PROGRAM AND AGRICULTURAL ACTIVITIES have recently been raised about the applicability of the Clean Water Act Section 404 Regulatory Program emphasize that we respect and support the underlying purposes of the Clean Water Act regarding the exemption

US Army Corps of Engineers

359

Endangered Species Act Biennial Report to  

E-print Network

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

360

New developments concerning the Equal Pay Act  

Microsoft Academic Search

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

Li Yun Chen; Brian H. Kleiner

1998-01-01

361

Uniform Management of Institutional Funds Act.  

ERIC Educational Resources Information Center

The purpose and provisions of the Uniform Management of Institutional Funds Act are analyzed, and the full text of the Act is presented. The Act was drafted in 1972 to remove uncertainties with respect to the nature of eleemosynary corporations, particularly colleges and universities and to the powers of their governing boards in the area of…

NACUBO Administrative Service/Supplement, 1980

1980-01-01

362

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

363

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

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

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

366

The mismetallation of enzymes during oxidative stress.  

PubMed

Mononuclear iron enzymes can tightly bind non-activating metals. How do cells avoid mismetallation? The model bacterium Escherichia coli may control its metal pools so that thermodynamics favor the correct metallation of each enzyme. This system is disrupted, however, by superoxide and hydrogen peroxide. These species oxidize ferrous iron and thereby displace it from many iron-dependent mononuclear enzymes. Ultimately, zinc binds in its place, confers little activity, and imposes metabolic bottlenecks. Data suggest that E. coli compensates by using thiols to extract the zinc and by importing manganese to replace the catalytic iron atom. Manganese resists oxidants and provides substantial activity. PMID:25160623

Imlay, James A

2014-10-10

367

Enzyme Regulation in C4 Photosynthesis 12  

PubMed Central

NADP-malate dehydrogenase, a light-modulated enzyme of C4 photosynthesis, was purified to homogeneity from leaves of corn. The pure enzyme was activated by thioredoxin m that was reduced either photochemically (with ferredoxin and ferredoxin-thioredoxin reductase) or chemically (with dithiothreitol). Unactivated corn leaf NADP-malate dehydrogenase had a molecular weight of 50,000 to 60,000 and was chromophorefree. The enzyme appeared to have a high content of serine and glycine and to contain both S—S and SH groups. Consequently, NADP-malate dehydrogenase seems to be capable of undergoing reversible oxidation/reduction during its photoregulation. PMID:16661905

Jacquot, Jean-Pierre P.; Buchanan, Bob B.; Martin, F.; Vidal, J.

1981-01-01

368

Characterization of CenC, an enzyme from Cellulomonas fimi with both endo- and exoglucanase activities.  

PubMed Central

The cenC gene, encoding beta-1,4-glucanase C (CenC) from Cellulomonas fimi, was overexpressed in Escherichia coli with a tac-based expression vector. The resulting polypeptide, with an apparent molecular mass of 130 kDa, was purified from the cell extracts by affinity chromatography on cellulose followed by anion-exchange chromatography. N-terminal sequence analysis showed the enzyme to be properly processed. Mature CenC was optimally active at pH 5.0 and 45 degrees C. The enzyme was extremely active on soluble, fluorophoric, and chromophoric glycosides (4-methylumbelliferyl beta-glycosides, 2'-chloro-4'-nitrophenyl-beta-D-cellobioside, and 2'-chloro-4'-nitrophenyl-lactoside) and efficiently hydrolyzed carboxymethyl cellulose, barley beta-glucan, lichenan, and, to a lesser extent, glucomannan. CenC also hydrolyzed acid-swollen cellulose, Avicel, and bacterial microcrystalline cellulose. However, degradation of the latter was slow compared with its degradation by CenB, another C. fimi cellulose belonging to the same enzyme family. CenC acted with inversion of configuration at the anomeric carbon, in accordance with its classification as a family 9 member. The enzyme released mainly cellobiose from soluble cellodextrins and insoluble cellulose. Attack appeared to be from the reducing chain ends. Analysis of carboxymethyl cellulose hydrolysis suggests that CenC is semiprocessive enzyme with both endo- and exoglucanase activities. PMID:8763951

Tomme, P; Kwan, E; Gilkes, N R; Kilburn, D G; Warren, R A

1996-01-01

369

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

370

Novel roles of neuropeptide processing enzymes: EC3.4.24.15 in the neurome.  

PubMed

Neuropeptide processing metalloenzymes, such as angiotensin converting enzyme, neprilysin, endothelin converting enzyme, neurolysin, and EC3.4.24.15 (EP24.15), are central to the formation and degradation of bioactive peptides. We present EP24.15 as a paradigm for novel functions ascribed to these enzymes in the neurome. Although the neurome typically encompasses proteomes of the brain and central nervous system, exciting new roles of these neuropeptidases have been demonstrated in other organ systems. We discuss the involvement of EP24.15 with clinical sequelae involving the use of gonadotropin-releasing hormone (GnRH; LHRH) analogs that act as enzyme inhibitors, in vascular physiology (blood pressure regulation), and in the hematologic system (immune surveillance). Hemodynamic forces, such as cyclic strain and shear stress, on vascular cells, induce an increase in EP24.15 transcription, suggesting that neuropeptidase-mediated hydrolysis of pressor/depressor peptides is likely regulated by changes in hemodynamic force and blood pressure. Lastly, EP24.15 regulates surface expression of major histocompatibility complex Class I proteins in vivo, suggesting that EP24.15 may play an important role in maintenance of immune privilege in sites of increased endogenous expression. In these extraneural systems, regulation of both neuropeptide and other peptide substrates by neuropeptidases indicates that the influence of these enzymes may be more global than was anticipated previously, and suggests that their attributed role as neuropeptidases underestimates their physiologic actions in the neural system. PMID:14598322

Kim, S I; Grum-Tokars, V; Swanson, T A; Cotter, E J; Cahill, P A; Roberts, J L; Cummins, P M; Glucksman, M J

2003-11-01

371

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

NASA Astrophysics Data System (ADS)

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

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

2007-07-01

372

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

373

21 CFR 864.9400 - Stabilized enzyme solution.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

374

21 CFR 184.1372 - Insoluble glucose isomerase enzyme preparations.  

Code of Federal Regulations, 2014 CFR

...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

375

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

376

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

377

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

378

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

379

21 CFR 864.9400 - Stabilized enzyme solution.  

Code of Federal Regulations, 2010 CFR

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2010-04-01

380

21 CFR 862.2500 - Enzyme analyzer for clinical use.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

381

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

382

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

383

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

384

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

385

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

386

21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

387

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

388

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

389

21 CFR 864.9400 - Stabilized enzyme solution.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

390

21 CFR 173.150 - Milk-clotting enzymes, microbial.  

Code of Federal Regulations, 2014 CFR

...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

391

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

392

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

393

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

394

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

395

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

396

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

397

Practical Enzyme Kinetics: A Biochemical Laboratory Experiment.  

ERIC Educational Resources Information Center

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

Rowe, H. Alan; Brown, Morris

1988-01-01

398

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

399

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

400

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

401

ACTS: Technology Description and Results  

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

402

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

PubMed Central

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

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

2011-01-01

403

Intracellular alginolytic enzymes of the marine bacterium Pseudoalteromonas citrea KMM 3297.  

PubMed

The marine bacterium Pseudoalteromonas citrea KMM 3297 is an associate of the holothurian Apostichopus japonicus. When grown in a medium containing glucose, the strain produces two intracellular alginolytic enzymes, AlI and AlII. Fucoidan from the brown alga Fucus evanescens induces synthesis of one more alginolytic enzyme, AlIII. These enzymes were separated using anion-exchange chromatography. The alginate lyase AlI completely retains its activity at 35 degrees C, AlII and AlIII being stable at 45 degrees C. The alginate lyases exhibit maximal activities in the range of pH 7-8. The molecular weights of AlI, AlII, and AlIII determined by gel filtration are 25, 79, and 61 kD, respectively. All the investigated enzymes are endo-type alginate lyases. They catalyze degradation of polyguluronate (poly-G) and polymannuronate (poly-M) yielding oligosaccharides of the polymerization degree of 5 > or = n > or = 3 with the unsaturated bond between the C4 and C5 atoms of the non-reducing terminus. A mixture of these three enzymes exhibits synergism while acting on the polymeric substrate. The Km values of the alginate lyase AlI for poly-G and poly-M are 24 and 34 micro g/ml, respectively. Alginate lyase AlIII exhibits less affinity to poly-M (Km = 130.0 microg/ml) than to poly-G (Km = 40.0 microg/ml). NaCl (0.2 M), MgCl2 and MgSO4 (0.01 M) activate all three enzymes more than twofold. The presence of several alginolytic enzymes of different specificity provides efficient destruction of alginic acids of brown algae by the strain P. citrea KMM 3297. PMID:15061691

Alekseeva, S A; Bakunina, I Yu; Nedashkovskaya, O I; Isakov, V V; Mikhailov, V V; Zvyagintseva, T N

2004-03-01

404

Ethylmalonyl-CoA decarboxylase, a new enzyme involved in metabolite proofreading.  

PubMed

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

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

2011-12-16

405

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

406

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

407

Productivity of hydrolytic enzymes by mycorrhizal mushrooms  

Microsoft Academic Search

To survey the potential for production of extracellular hydrolytic enzymes by mycorrhizal mushrooms, productivities of these exo-enzymes from mycelia on potato-dextrose liquid medium were determined.Tricholoma matsutake produced relatively high levels of CM-cellulase and avicelase activities in all test strains. It also produced higher activity of acid proteinase than neutral proteinase. Its xylanase activities seemed to be higher than those of

Takao Terashita; Matashi Kono; Kentaro Yoshikawa; Jiko Shishiyama

1995-01-01

408

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

409

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

410

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

411

Cyanide-degrading enzymes for bioremediation  

E-print Network

CYANIDE-DEGRADING ENZYMES FOR BIOREMEDIATION A Thesis by LACY JAMEL BASILE Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... August 2008 Major Subject: Microbiology CYANIDE-DEGRADING ENZYMES FOR BIOREMEDIATION A Thesis by LACY JAMEL BASILE Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements...

Basile, Lacy Jamel

2008-10-10

412

National Energy Act statutes and solar energy  

SciTech Connect

The National Energy Act of 1978 contains many provisions that will significantly affect solar technology commercialization and solar energy users. Four of the five statutes that comprise the National Energy Act deserve close attention. The National Energy Conservation Policy Act will promote residential solar installations. The Energy Tax Act will accelerate both residential and commercial solar system applications. The Public Utilities Regulatory Policies Act promotes efficient use of utility resources as well as decentralized power production. And, the Power Plan and Industrial Fuel Use Act places severe restrictions on future burning of petroleum and natural gas, which should lead some operators to build or convert to solar energy systems. Each of the preceding acts are considered in separate sections of this report. Federal regulations issued pursuant to the various provisions are also identified and discussed, and some of the problems with the provisions and regulations are noted.

Howard, J.

1980-02-01

413

Estuary Restoration Act of 2000 Title I of Estuaries and Clean Waters Act of 2000  

E-print Network

Estuary Restoration Act of 2000 Title I of Estuaries and Clean Waters Act of 2000 Public Law 106 of Section 108 of the Estuary Restoration Act, Title I of P.L. 106-457 (Act). This report covers the fiscal years 2004 through 2006 and reflects the views of the Estuary Habitat Restoration Council (Council

US Army Corps of Engineers

414

Enzyme-based antifouling coatings: a review.  

PubMed

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

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

2007-01-01

415

Enzyme catalysis: Cleaner, safer, energy efficient  

SciTech Connect

Protein catalysts, more commonly referred to as enzymes, are the driving force behind the myriad of chemical reactions occurring in living organisms. By using their ability to distinguish between similar biochemical compounds and optical isomers (enantiomers), with virtually complete discrimination, enzymes are efficient catalysts, making them an attractive alternative for synthetic ones. Tapping into the natural abilities of enzymes, the chemical process industries (CPI) are beginning to realize that enzymes are not only effective for catalyzing reactions of natural compounds within living systems, but that they can also be used to catalyze reactions of unnatural compounds. Enzymes are novel among catalysts in that they are capable of directing asymmetric transformations with complete activity under ambient conditions. As a result, bioconversions, such as the hydroxylation of unactivated hydrocarbon centers, to give alcohols in high optical purity, have few counterparts in traditional chemical catalysis. And unlike most chemical manufacturing catalysts, enzymes work in water, at ambient temperature and near neutral pH. Also, they are easy to dispose of, since they are composed of biodegradable protein. Thus, biocatalysts are the ideal green catalyst, producing less waste and consuming less energy.

Lalonde, J. [Altus Biologics, Inc., Cambridge, MA (United States)

1997-09-01

416

Activity assessment of microbial fibrinolytic enzymes.  

PubMed

Conversion of fibrinogen to fibrin inside blood vessels results in thrombosis, leading to myocardial infarction and other cardiovascular diseases. In general, there are four therapy options: surgical operation, intake of antiplatelets, anticoagulants, or fibrinolytic enzymes. Microbial fibrinolytic enzymes have attracted much more attention than typical thrombolytic agents because of the expensive prices and the side effects of the latter. The fibrinolytic enzymes were successively discovered from different microorganisms, the most important among which is the genus Bacillus. Microbial fibrinolytic enzymes, especially those from food-grade microorganisms, have the potential to be developed as functional food additives and drugs to prevent or cure thrombosis and other related diseases. There are several assay methods for these enzymes; this may due to the insolubility of substrate, fibrin. Existing assay methods can be divided into three major groups. The first group consists of assay of fibrinolytic activity with natural proteins as substrates, e.g., fibrin plate methods. The second and third groups of assays are suitable for kinetic studies and are based on the determination of hydrolysis of synthetic peptide esters. This review will deal primarily with the microorganisms that have been reported in literature to produce fibrinolytic enzymes and the first review discussing the methods used to assay the fibrinolytic activity. PMID:23812278

Kotb, Essam

2013-08-01

417

A novel enzyme, L-tryptophan oxidase, from a basidiomycete, Coprinus sp. SF-1: purification and characterization.  

PubMed

A basidiomycete, Coprinus sp. SF-1, was found to produce an L-Trp-oxidizing enzyme by screening from the culture collection of our laboratory. After solubilization by 1 M NaSCN from the particulate fraction of disrupted cells of the strain, the enzyme was purified about 76-fold to essential homogeneity. The enzyme had a molecular mass of about 420 kDa and the subunit molecular mass was 68 kDa. The enzyme contained 1 mol of non-covalently bound FAD per mol of the subunit. It catalyzed the simultaneous reactions of oxidative deamination and oxygenative decarboxylation of L-Trp to form indolepyruvic acid and indole-3-acetamide, the former of which was further oxidized to indole-3-acetic acid. The molar ratio of the respective reaction products was about 9:1. The enzyme specifically oxidized L-Trp, and slightly acted on L-Phe and L-Tyr. The Km for L-Trp was about 0.5 mM in both oxidase and oxygenase reactions. Thus, the enzyme is a novel one and was tentatively designated "L-Trp oxidase (deaminating and decarboxylating)". The optimum pHs of oxidase and oxygenase activities were 7.0 and 9.0, respectively. The optimum temperatures of both activities were 50 degrees C. The enzyme was stable at pH 6.0-10.5 and below 50 degrees C, and at 4 degrees C for 1 year. PMID:10945268

Furuya, Y; Sawada, H; Hirahara, T; Ito, K; Ohshiro, T; Izumi, Y

2000-07-01

418

Improvement of an antibody-enzyme coupling yield by enzyme surface supercharging.  

PubMed

BackgroundProtein cross-coupling reactions demand high yields, especially if the products are intended for bioanalytics, like enzyme-linked immunosorbent assays. Amongst other factors, the coupling yield depends on the concentration of the proteins being used for coupling. Protein supercharging of enzymes can increase the solubility dramatically, which could promote enzyme-antibody coupling reactions. A highly soluble, supercharged variant of the enzyme human enteropeptidase light chain was created by a site-directed mutagenesis of surface amino acids, used for the production of an antibody-enzyme conjugate and compared to the wild type enzyme.ResultsWild type and mutant enzyme could successfully be cross-coupled to an antibody to give antibody-enzyme conjugates suitable for ELISA. Their assay performances and the analysis of the enzyme activities in solution demonstrate that the supercharged version could be coupled to a higher extent, which resulted in better assay sensitivities. The generated conjugate, based on the supercharged enzyme, was feasible as a reporter molecule in a sandwich ELISA and allowed the detection of epidermal growth factor with a detection limit of 15.63 pg (25 pmol/L).ConclusionThe highly soluble, surface supercharged, human enteropeptidase light chain mutant provided better yields in coupling the enzyme to an antibody than the wild type. This is most likely related to the higher protein concentration during the coupling. The data suggest that supercharging can be applied favourably to other proteins which have to be covalently linked to other polymers or surfaces with high yields without losses in enzyme activity or specificity. PMID:25326050

Prasse, Agneta A; Zauner, Thomas; Büttner, Karin; Hoffmann, Ralf; Zuchner, Thole

2014-10-18

419

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

PubMed

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

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

2013-11-19

420

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

421

78 FR 37799 - Privacy Act of 1974; System of Records  

Federal Register 2010, 2011, 2012, 2013, 2014

...Privacy Act Program Manager, Corporate Communications, DFAS-ZCF/IN...Privacy Act Program Manager, Corporate Communications, DFAS-ZCF/IN...Privacy Act Program Manager, Corporate Communications, [[Page...

2013-06-24

422

77 FR 58106 - Privacy Act of 1974; System of Records  

Federal Register 2010, 2011, 2012, 2013, 2014

...Privacy Act Program Manager, Corporate Communications, DFAS-HKC/IN...Privacy Act Program Manager, Corporate Communications, DFAS-HKC/IN...Privacy Act Program Manager, Corporate Communications, DFAS-...

2012-09-19

423

PIASx acts as an Elk-1 coactivator by facilitating derepression  

PubMed Central

The ETS-domain transcription factor Elk-1 is a MAP kinase-inducible transcriptional activator protein. However, in the basal state, its activity is repressed by SUMO-dependent histone deacetylase (HDAC) recruitment. Relief of this repression accompanies the activation process. Here, we demonstrate that PIASx? acts to facilitate this derepression process. Members of the PIAS family of proteins can act as E3 enzymes that enhance the sumoylation status of a variety of substrates. However, PIASx-mediated coactivation of Elk-1 occurs in an E3 activity-independent manner. PIASx? binds to Elk-1 in vivo and enhances its transcriptional activity. The coactivating properties of PIASx? require Elk-1 to be modified with SUMO and the integrity of the SUMO binding motif in PIASx?. PIASx? activates Elk-1 through alterations in the HAT/HDAC activities associated with Elk-1. In particular, PIASx? facilitates the loss of the repressive HDAC-2 from sumoylated Elk-1, a key event in the activation of Elk-1 in response to signalling through the ERK MAP kinase pathway. Our data therefore reveal a novel coactivator function for PIASx? through reversing SUMO-mediated repression of transcription factor activity. PMID:15920481

Yang, Shen-Hsi; Sharrocks, Andrew D

2005-01-01

424

Occurrence of enzymes involved in biosynthesis of indole-3-acetic acid from indole-3-acetonitrile in plant-associated bacteria, Agrobacterium and Rhizobium.  

PubMed Central

The occurrence of a hitherto unknown pathway involving the action of two enzymes, a nitrile hydratase and an amidase for the biosynthesis of indole-3-acetic acid was discovered in phytopathogenic bacteria Agrobacterium tumefaciens and in leguminous bacteria Rhizobium. The nitrile hydratase acting on indole-3-acetonitrile was purified to homogeneity through only two steps from the cell-free extract of A. tumefaciens. The molecular mass of the purified enzyme estimated by HPLC was about 102 kDa, and the enzyme consisted of four subunits identical in molecular mass. The enzyme exhibited a broad absorption spectrum in the visible range with absorption maxima at 408 nm and 705 nm, and it contained cobalt and iron. The enzyme stoichiometrically catalyzed the hydration of indole-3-acetonitrile into indole-3-acetamide with a specific activity of 13.7 mol per min per mg and a Km of 7.9 microM. Images Fig. 1 PMID:11607511

Kobayashi, M; Suzuki, T; Fujita, T; Masuda, M; Shimizu, S

1995-01-01

425

Occurrence of enzymes involved in biosynthesis of indole-3-acetic acid from indole-3-acetonitrile in plant-associated bacteria, Agrobacterium and Rhizobium.  

PubMed

The occurrence of a hitherto unknown pathway involving the action of two enzymes, a nitrile hydratase and an amidase for the biosynthesis of indole-3-acetic acid was discovered in phytopathogenic bacteria Agrobacterium tumefaciens and in leguminous bacteria Rhizobium. The nitrile hydratase acting on indole-3-acetonitrile was purified to homogeneity through only two steps from the cell-free extract of A. tumefaciens. The molecular mass of the purified enzyme estimated by HPLC was about 102 kDa, and the enzyme consisted of four subunits identical in molecular mass. The enzyme exhibited a broad absorption spectrum in the visible range with absorption maxima at 408 nm and 705 nm, and it contained cobalt and iron. The enzyme stoichiometrically catalyzed the hydration of indole-3-acetonitrile into indole-3-acetamide with a specific activity of 13.7 mol per min per mg and a Km of 7.9 microM. PMID:11607511

Kobayashi, M; Suzuki, T; Fujita, T; Masuda, M; Shimizu, S

1995-01-31

426

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

427

Purification and characterization of a coagulant enzyme, okinaxobin I, from the venom of Trimeresurus okinavensis (Himehabu snake) which releases fibrinopeptide B.  

PubMed

A coagulant enzyme, named okinaxobin I, has been purified to homogeneity from the venom of Trimeresurus okinavensis (Himehabu) by chromatographies on Sephadex G-100 and CM-Toyopearl 650M columns. The enzyme was a monomer with a molecular weight of 37,000 and its isoelectric point was 5.4. The enzyme acted on fibrinogen to form fibrin clots with a specific activity of 77 NIH units/mg. Fibrinopeptide B was released at a rate much faster than fibrinopeptide A. The enzyme exhibited 2 to 3 times higher activity toward tosyl-L-arginine methyl ester and benzoyl-L-arginine p-nitroanilide than bovine thrombin. The esterase activity was strongly inhibited by diisopropylfluorophosphate and phenylmethanesulfonyl fluoride, and to a lesser extent by tosyl-L-lysine chloromethyl ketone, indicating that the enzyme is a serine protease like thrombin. The N-terminal sequence was highly homologous to those of coagulant enzymes from T. flavoviridis and Bothrops atrox, moojeni venoms which preferentially release fibrinopeptide A. In order to remove most, if not all, of the bonded carbohydrates, the enzyme was treated with anhydrous hydrogen fluoride (HF), thereby reducing the molecular weight to 30,000. The protein contained approximately 260 amino acid residues when computation was based on this value. The HF-treated enzyme retained about 50% of the clotting and esterolytic (TAME) activities and preferentially released fibrinopeptide B from fibrinogen. The carbohydrate moiety is not crucial for enzyme activity but might be necessary for eliciting full activity. PMID:1964457

Iwasaki, A; Shieh, T C; Shimohigashi, Y; Waki, M; Kihara, H; Ohno, M

1990-11-01

428

Towards structured output prediction of enzyme function  

PubMed Central

Background In this paper we describe work in progress in developing kernel methods for enzyme function prediction. Our focus is in developing so called structured output prediction methods, where the enzymatic reaction is the combinatorial target object for prediction. We compared two structured output prediction methods, the Hierarchical Max-Margin Markov algorithm (HM3) and the Maximum Margin Regression algorithm (MMR) in hierarchical classification of enzyme function. As sequence features we use various string kernels and the GTG feature set derived from the global alignment trace graph of protein sequences. Results In our experiments, in predicting enzyme EC classification we obtain over 85% accuracy (predicting the four digit EC code) and over 91% microlabel F1 score (predicting individual EC digits). In predicting the Gold Standard enzyme families, we obtain over 79% accuracy (predicting family correctly) and over 89% microlabel F1 score (predicting superfamilies and families). In the latter case, structured output methods are significantly more accurate than nearest neighbor classifier. A polynomial kernel over the GTG feature set turned out to be a prerequisite for accurate function prediction. Combining GTG with string kernels boosted accuracy slightly in the case of EC class prediction. Conclusion Structured output prediction with GTG features is shown to be computationally feasible and to have accuracy on par with state-of-the-art approaches in enzyme function prediction. PMID:19091049

Astikainen, Katja; Holm, Liisa; Pitkänen, Esa; Szedmak, Sandor; Rousu, Juho

2008-01-01

429

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

430

A multi-enzyme model for Pyrosequencing.  

PubMed

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 K(M) 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

431

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

432

Application of enzymes in anaerobic digestion.  

PubMed

Owing to the very low economic value of brewer's spent grains, its utilisation for biogas production is very promising. The hydrolysis of ligno-cellulose is the rate limiting step in anaerobic digestion. Enzymatic pre-treatment promotes the hydrolysis of ligno-cellulose, breaking it down to lower molecular weight substances which are ready to be utilised by the bacteria. A cheap raw multi-enzyme produced by a solid state fermentation (SSF) process is a good substitute for expensive conventional enzyme. The SSF enzyme application to spent grain has been investigated by carrying out enzymatic solubility tests, hydrolytic experiments and two-step anaerobic fermentation of spent grain. Gas chromatograph analysis was conducted to quantify fatty acids concentrations, while CH(4), CO(2), O(2), H(2) and H(2)S were measured to determine biogas quality by means of a gas analyser. DS, oDS, pH were also measured to analyse the anaerobic digestion. The result shows that enzyme application promotes the hydrolysis of ligno-cellulose, indicated by higher enzymatic solubility and fatty acid concentration in a hydrolytic bioreactor. Moreover, biogas production is also increased. The quality of the gases produced is also enhanced. Since the anaerobic digestion can be operated in a stable performance, it can also be concluded that SSF enzyme is compatible with anaerobic digestion. PMID:18048974

Bochmann, G; Herfellner, T; Susanto, F; Kreuter, F; Pesta, G

2007-01-01

433

Pancreatic enzyme replacement therapy during pancreatic insufficiency.  

PubMed

Pancreatic stimulation and therefore digestion is a tightly controlled and hormonally mediated process. Any alterations affecting any of the systematic steps for successful digestion and absorption to occur will impair appropriate pancreatic enzymatic secretion, entry into the bowel lumen, functionality once inside the lumen, and thus appropriate mixing with foods and nutrients. Many causes of pancreatic insufficiency may require the initiation of pancreatic enzyme therapy, including but not limited to cystic fibrosis, pancreatic cancer, acute and chronic pancreatitis, and pancreatic surgery. This purpose of this article is to help clarify the conditions that cause pancreatic insufficiency, how to determine if the patient is malabsorbing, and the best use of pancreatic enzyme replacement therapy for treatment in these conditions. The first step in determining if pancreatic enzyme therapy is appropriate is to determine if the patient is malabsorbing specifically due to pancreatic exocrine insufficiency. An overview of the methods used to determine pancreatic insufficiency is provided, as well as appropriate treatment methods. Recent Food and Drug Administration regulations require a more thorough process, including randomized controlled trials to prove the safety and efficacy of pancreatic enzymes, to approve them for use. The studies used to verify efficacy also are examined. Last, dosing guidelines and some unconventional ways to administer pancreatic enzymes, such as during enteral feedings, are reviewed. PMID:24687867

Berry, Amy J

2014-06-01

434

Endangered Species Act Biennial Report to  

E-print Network

. . . . . . . . . . . . . . . . . . . . . . . . . . . 88 #12;Endangered Species Act Biennial Report to Congress Sockeye Salmon: Oncorhynchus nerka . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Chinook Salmon: Oncorhynchus tshawytscha . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Chum Salmon: Oncorhynchus keta

435

Enhanced enzyme activity in silicon integrated enzyme reactors utilizing porous silicon as the coupling matrix  

Microsoft Academic Search

The performance of porous silicon as a coupling matrix for silicon integrated enzyme reactors has been investigated. A porous silicon layer in a water is expected to yield an increased catalytic activity when coupling an enzyme to the wafer due to the surface enlargement of the porous structure. The porous silicon layer is obtained by anodizing a 1 cm x

Thomas Laurell; Johan Drott; Lars Rosengren; Kjell Lindström

1996-01-01

436

Novel enzyme activities and functional plasticity revealed by recombining highly homologous enzymes  

Microsoft Academic Search

Background: Directed evolution by DNA shuffling has been used to modify physical and catalytic properties of biological systems. We have shuffled two highly homologous triazine hydrolases and conducted an exploration of the substrate specificities of the resulting enzymes to acquire a better understanding of the possible distributions of novel functions in sequence space.Results: Both parental enzymes and a library of

SunAi Raillard; Anke Krebber; Yonghong Chen; Jon E Ness; Ericka Bermudez; Rossana Trinidad; Rachel Fullem; Christopher Davis; Mark Welch; Jennifer Seffernick; Lawrence P Wackett; Willem P. C Stemmer; Jeremy Minshull

2001-01-01

437

Nanomaterials with enzyme-like characteristics (nanozymes): next-generation artificial enzymes.  

PubMed

Over the past few decades, researchers have established artificial enzymes as highly stable and low-cost alternatives to natural enzymes in a wide range of applications. A variety of materials including cyclodextrins, metal complexes, porphyrins, polymers, dendrimers and biomolecules have been extensively explored to mimic the structures and functions of naturally occurring enzymes. Recently, some nanomaterials have been found to exhibit unexpected enzyme-like activities, and great advances have been made in this area due to the tremendous progress in nano-research and the unique characteristics of nanomaterials. To highlight the progress in the field of nanomaterial-based artificial enzymes (nanozymes), this review discusses various nanomaterials that have been explored to mimic different kinds of enzymes. We cover their kinetics, mechanisms and applications in numerous fields, from biosensing and immunoassays, to stem cell growth and pollutant removal. We also summarize several approaches to tune the activities of nanozymes. Finally, we make comparisons between nanozymes and other catalytic materials (other artificial enzymes, natural enzymes, organic catalysts and nanomaterial-based catalysts) and address the current challenges and future directions (302 references). PMID:23740388

Wei, Hui; Wang, Erkang

2013-07-21

438

ENZVU--An Enzyme Kinetics Computer Simulation Based upon a Conceptual Model of Enzyme Action.  

ERIC Educational Resources Information Center

Discusses a simulation on enzyme kinetics based upon the ability of computers to generate random numbers. The program includes: (1) enzyme catalysis in a restricted two-dimensional grid; (2) visual representation of catalysis; and (3) storage and manipulation of data. Suggested applications and conclusions are also discussed. (DH)

Graham, Ian

1985-01-01

439

Identification and Structural Analysis of an l-Asparaginase Enzyme from Guinea Pig with Putative Tumor Cell Killing Properties.  

PubMed

The initial observation that guinea pig serum kills lymphoma cells marks the serendipitous discovery of a new class of anti-cancer agents. The serum cell killing factor was shown to be an enzyme with l-asparaginase (ASNase) activity. As a direct result of this observation, several bacterial l-asparaginases were developed and are currently approved by the Food and Drug Administration for the treatment of the subset of hematological malignancies that are dependent on the extracellular pool of the amino acid asparagine. As drugs, these enzymes act to hydrolyze asparagine to aspartate, thereby starving the cancer cells of this amino acid. Prior to the work presented here, the precise identity of this guinea pig enzyme has not been reported in the peer-reviewed literature. We discovered that the guinea pig enzyme annotated as H0W0T5_CAVPO, which we refer to as gpASNase1, has the required low Km property consistent with that possessed by the cell-killing guinea pig serum enzyme. Elucidation of the ligand-free and aspartate complex gpASNase1 crystal structures allows a direct comparison with the bacterial enzymes and serves to explain the lack of l-glutaminase activity in the guinea pig enzyme. The structures were also used to generate a homology model for the human homolog hASNase1 and to help explain its vastly different kinetic properties compared with gpASNase1, despite a 70% sequence identity. Given that the bacterial enzymes frequently present immunogenic and other toxic side effects, this work suggests that gpASNase1 could be a promising alternative to these bacterial enzymes. PMID:25320094

Schalk, Amanda M; Nguyen, Hien-Anh; Rigouin, Coraline; Lavie, Arnon

2014-11-28

440

21 CFR 184.1287 - Enzyme-modified fats.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Enzyme-modified fats. 184.1287...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...184.1287 Enzyme-modified fats. (a) Enzyme-modified...safe (GRAS). Enzyme-modified milk powder may...safe (GRAS) as direct human food ingredients...

2014-04-01

441

Evolution of extracellular enzyme activities during manure composting  

E-print Network

Evolution of extracellular enzyme activities during manure composting S.M. Tiquia Environmental to determine the extracellular enzyme pro®les during composting, relate the activities of these enzymes manure composting. Results showed an overall increase in diversity and relative abundance of enzymes

Tiquia-Arashiro, Sonia M.

442

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

443

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.

444

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

445

21 CFR 184.1287 - Enzyme-modified fats.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 false Enzyme-modified fats. 184.1287 Section 184.1287 Food and...Affirmed as GRAS § 184.1287 Enzyme-modified fats. (a) Enzyme-modified refined beef fat, enzyme-modified butterfat, and...

2011-04-01

446

Seeing & Feeling How Enzymes Work Using Tangible Models  

ERIC Educational Resources Information Center

This article presents a tangible model used to help students tackle some misconceptions about enzyme actions, particularly the induced-fit model, enzyme-substrate complementarity, and enzyme inhibition. The model can simulate how substrates induce a change in the shape of the active site and the role of attraction force during enzyme-substrate…

Lau, Kwok-chi

2013-01-01

447

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

448

Chemical Probes for Histone-Modifying Enzymes  

PubMed Central

Summary Central to the epigenetic regulation of chromatin remodeling are the histone-modifying enzymes which catalyze reversible lysine acetylation and methylation. From the early discovery of histone deacetylase inhibitors to the more recent identification of histone demethylase blockers, chemical approaches offer increasingly sophisticated tools for the interrogation of the structure and function of these lysine-modifying enzymes. This review will summarize progress to date on compounds identified from screens or by design that can modulate the activity of classical histone deacetylases, sirtuins, histone acetyltransferses, histone methyltransferases, and histone demethylases. We will highlight applications of compounds to mechanistic and functional studies involving these enzymes and discuss future challenges regarding target specificity and general utility. PMID:18800048

Cole, Philip A.

2010-01-01

449

Histone Modifying Enzymes: Structures, Mechanisms, and Specificities  

PubMed Central

Histone modifying enzymes catalyze the addition or removal of an array of covalent modifications in histones and non-histone proteins. Within the context of chromatin, these modifications regulate gene expression as well as other genomic functions and have been implicated in establishing and maintaining a heritable epigenetic code that contributes to defining cell identity and fate. Biochemical and structural characterization of histone modifying enzymes has yielded important insights into their respective catalytic mechanisms, substrate specificities, and regulation. In this review, we summarize recent advances in understanding these enzymes, highlighting studies of the histone acetyltransferases (HATs) p300 (also now known as KAT3B) and Rtt109 (KAT11) and the histone lysine demethylases (HDMs) LSD1 (KDM1) and JMJD2A (KDM4A), present overriding themes that derive from these studies, and pose remaining questions concerning their regulatory roles in mediating DNA transactions. PMID:18722564

Marmorstein, Ronen; Trievel, Raymond C.

2014-01-01

450

Enzymes without borders: mobilizing substrates, delivering products.  

PubMed

Many cellular reactions involve both hydrophobic and hydrophilic molecules that reside within the chemically distinct environments defined by the phospholipid-based membranes and the aqueous lumens of cytoplasm and organelles. Enzymes performing this type of reaction are required to access a lipophilic substrate located in the membranes and to catalyze its reaction with a polar, water-soluble compound. Here, we explore the different binding strategies and chemical tricks that enzymes have developed to overcome this problem. These reactions can be catalyzed by integral membrane proteins that channel a hydrophilic molecule into their active site, as well as by water-soluble enzymes that are able to capture a lipophilic substrate from the phospholipid bilayer. Many chemical and biological aspects of this type of enzymology remain to be investigated and will require the integration of protein chemistry with membrane biology. PMID:18621661

Forneris, Federico; Mattevi, Andrea

2008-07-11

451

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

452

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

453

Entrapping Enzyme in a Functionalized Nanoporous Support  

SciTech Connect

The enzyme organophosphorus hydrolase (OPH) was spontaneously entrapped in carboxylethyl- or aminopropyl-functionalized mesoporous silica with rigid, uniform open-pore geometry (30 nm). This approach yielded larger amounts of protein loading and much higher specific activity of the enzyme when compared to the unfunctionalized mesoporous silica and normal porous silica with the same pore size. When OPH was incubated with the functionalized mesoporous silica, protein molecules were sequestered in or excluded from the porous material, depending on electrostatic interaction with the charged functional groups. OPH entrapped in the organically functionalized nanopores showed an exceptional high immobilization efficiency of more than 200% and enhanced stability far exceeding that of the free enzyme in solution. The combination of high protein loading, high immobilization efficiency and stability is attributed to the large and uniform pore structure, and to the optimum environment introduced by the functional groups.

Lei, Chenghong; Shin, Yongsoon; Liu, Jun; Ackerman, Eric J.

2002-09-25

454

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

455

Enzymes Without Borders: Mobilizing Substrates, Delivering Products  

NSDL National Science Digital Library

Many cellular reactions involve both hydrophobic and hydrophilic molecules that reside within the chemically distinct environments defined by the phospholipid-based membranes and the aqueous lumens of cytoplasm and organelles. Enzymes performing this type of reaction are required to access a lipophilic substrate located in the membranes and to catalyze its reaction with a polar, water-soluble compound. Here, we explore the different binding strategies and chemical tricks that enzymes have developed to overcome this problem. These reactions can be catalyzed by integral membrane proteins that channel a hydrophilic molecule into their active site, as well as by water-soluble enzymes that are able to capture a lipophilic substrate from the phospholipid bilayer. Many chemical and biological aspects of this type of enzymology remain to be investigated and will require the integration of protein chemistry with membrane biology.

Federico Forneris (University of Pavia;Department of Genetics and Microbiology); Andrea Mattevi (University of Pavia;Department of Genetics and Microbiology)

2008-07-11

456

Controlling reaction specificity in pyridoxal phosphate enzymes  

PubMed Central

Pyridoxal 5'-phosphate enzymes are ubiquitous in the nitrogen metabolism of all organisms. They catalyze a wide variety of reactions including racemization, transamination, decarboxylation, elimination, retro-aldol cleavage, Claisen condensation, and others on substrates containing an amino group, most commonly ?-amino acids. The wide variety of reactions catalyzed by PLP enzymes is enabled by the ability of the covalent aldimine intermediate formed between substrate and PLP to stabilize carbanionic intermediates at C? of the substrate. This review attempts to summarize the mechanisms by which reaction specificity can be achieved in PLP enzymes by focusing on three aspects of these reactions: stereoelectronic effects, protonation state of the external aldimine intermediate, and interaction of the carbanionic intermediate with the protein side chains present in the active site. PMID:21664990

Toney, Michael D.

2012-01-01

457

75 FR 63824 - Privacy Act of 1974; System of Records  

Federal Register 2010, 2011, 2012, 2013, 2014

...Prevention Act; 28 U.S.C. 534, Uniform Federal Crime Reporting Act...C. 10601, Victims Rights and Restitution...Prevention Act; 28 U.S.C. 534, Uniform Federal Crime Reporting Act...C. 10601, Victims Rights and...

2010-10-18

458

76 FR 37095 - Privacy Act of 1974; System of Records  

Federal Register 2010, 2011, 2012, 2013, 2014

...computer matching requirements of the Privacy Act of 1974, as amended, under a computer...integrity and ensuring compliance with the Privacy Act; (g) To support Federal budget...Freedom of Information Act (FOIA) or Privacy Act Advice Disclosure. The...

2011-06-24

459

78 FR 38963 - Privacy Act of 1974; System of Records  

Federal Register 2010, 2011, 2012, 2013, 2014

...computer matching requirements of the Privacy Act of 1974, as amended, under a computer...integrity and ensuring compliance with the Privacy Act; (g) To support Federal budget...Freedom of Information Act (FOIA) or Privacy Act Advice Disclosure. The...

2013-06-28

460

Board-invited review: Opportunities and challenges in using exogenous enzymes to improve ruminant production.  

PubMed

The ability of ruminants to convert plant biomass unsuitable for human consumption into meat and milk is of great societal and agricultural importance. However, the efficiency of this process is largely dependent on the digestibility of plant cell walls. Supplementing ruminant diets with exogenous enzymes has the potential to improve plant cell wall digestibility and thus the efficiency of feed utilization. Understanding the complexity of the rumen microbial ecosystem and the nature of its interactions with plant cell walls is the key to using exogenous enzymes to improve feed utilization in ruminants. The variability currently observed in production responses can be attributed to the array of enzyme formulations available, their variable activities, the level of supplementation, mode of delivery, and the diet to which they are applied as well as the productivity level of the host. Although progress on enzyme technologies for ruminants has been made, considerable research is still required if successful formulations are to be developed. Advances in DNA and RNA sequencing and bioinformatic analysis have provided novel insight into the structure and function of rumen microbial populations. Knowledge of the rumen microbial ecosystem and its associated carbohydrases could enhance the likelihood of achieving positive responses to enzyme supplementation. The ability to sequence microbial genomes represents a valuable source of information in terms of the physiology and function of both culturable and unculturable rumen microbial species. The advent of metagenomic, metatranscriptomic, and proteomic techniques will further enhance our understanding of the enzymatic machinery involved in cell wall degradation and provide a holistic view of the microbial community and the complexities of plant cell wall digestion. These technologies should provide new insight into the identification of exogenous enzymes that act synergistically with the rumen microbial populations that ultimately dictate the efficiency of feed digestion. PMID:24363327

Meale, S J; Beauchemin, K A; Hristov, A N; Chaves, A V; McAllister, T A

2014-02-01

461

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

462

Engineered calcium-precipitable restriction enzyme.  

PubMed

We have developed a simple system for tagging and purifying proteins. Recent experiments have demonstrated that RTX (Repeat in Toxin) motifs from the adenylate cyclase toxin gene (CyaA) of B. pertussis undergo a conformational change upon binding calcium, resulting in precipitation of fused proteins and making this method a viable alternative for bioseparation. We have designed an iGEM Biobrick comprised of an RTX tag that can be easily fused to any protein of interest. In this paper, we detail the process of creating an RTX tagged version of the restriction enzyme EcoRI and describe a method for expression and purification of the functional enzyme. PMID:25524101

Hendrix, Josephina; Read, Timothy; Lalonde, Jean-Francois; Jensen, Phillip K; Heymann, William; Lovelace, Elijah; Zimmermann, Sarah A; Brasino, Michael; Rokicki, Joseph; Dowell, Robin D

2014-12-19

463

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

464

Recent advances in rational approaches for enzyme engineering  

PubMed Central

Enzymes are an attractive alternative in the asymmetric syntheses of chiral building blocks. To meet the requirements of industrial biotechnology and to introduce new functionalities, the enzymes need to be optimized by protein engineering. This article specifically reviews rational approaches for enzyme engineering and de novo enzyme design involving structure-based approaches developed in recent years for improvement of the enzymes’ performance, broadened substrate range, and creation of novel functionalities to obtain products with high added value for industrial applications. PMID:24688651

Steiner, Kerstin; Schwab, Helmut

2012-01-01

465

Freedom of Information Act - Team Science Toolkit  

Cancer.gov

The Freedom of Information Act (FOIA), 5 U.S.C. 552 provides individuals with a right to access information in the possession of the U.S. federal government. The government, however, may withhold information covered by 9 exemptions and 3 exclusions contained in the Act.

466

Faces of the Recovery Act: Sun Catalytix  

ScienceCinema

BOSTON- At the Massachusetts Institute of Technology, Dan Nocera talks about Sun Catalytix, the next generation of solar energy, and ARPA-E funding through the Recovery Act. To learn about more ARPA-E projects through the Recovery Act: http://arpa-e.energy.gov/FundedProjects.aspx

Nocera, Dave

2013-05-29

467

Environmental Politics and the Endangered Species Act.  

ERIC Educational Resources Information Center

Explores the controversial issue of the Endangered Species Act (ESA) discussing the Act and the scope of the extinction problem. Reviews the arguments for and against the ESA, addresses the tactics that have been used in the political struggle over the ESA, and highlights the future of the ESA. Includes teaching activities. (CMK)

Sahr, David

2000-01-01

468

Update on the Americans with Disabilities Act  

ERIC Educational Resources Information Center

In 1990, Congress enacted the Americans with Disabilities Act as a comprehensive mandate to eliminate discrimination against individuals with disabilities. The ADA's primary intent was to extend the protection of Section 504 of the Rehabilitation Act of 1973. The major difference between the two laws is that Section 504 applies to programs that…

Russo, Charles J.; Osborne, Allan G.

2009-01-01

469

Language and Legal Speech Acts: Decisions.  

ERIC Educational Resources Information Center

The first part of this essay argues specifically that legal speech acts are not statements but question/answer constructions. The focus in this section is on the underlying interrogative structure of the legal decision. The second part of the paper touches on significant topics related to the concept of legal speech acts, including the philosophic…

Kevelson, Roberta

470

THE VOCATIONAL EDUCATION ACT OF 1963.  

ERIC Educational Resources Information Center

THE VOCATIONAL EDUCATION ACT OF 1963 WAS ENACTED BY CONGRESS TO OFFER NEW AND EXPANDED VOCATIONAL EDUCATION PROGRAMS TO BRING JOB TRAINING INTO HARMONY WITH THE INDUSTRIAL, ECONOMIC, AND SOCIAL REALITIES OF TODAY AND THE NEEDS FOR TOMORROW. THE ACT IS COMPREHENSIVE. IT IS AVAILABLE TO AND CONCERNED ABOUT UNEMPLOYED AND EMPLOYED WORKERS OF ALL AGES…

Office of Education (DHEW), Washington, DC.

471

A NEW TENURE ACT. MIMEOGRAPH MONOGRAPH SERIES.  

ERIC Educational Resources Information Center

THIS DOCUMENT CONTAINS A PROPOSAL FOR A NEW TENURE ACT FOR TEACHERS. SEVEN UNIQUE FEATURES OF THE ACT ARE NOTED--(1) IT COVERS EVERYONE EXCEPT THE ASSISTANT SUPERINTENDENT AND THE SUPERINTENDENT, (2) PROBATION IS LIMITED TO TWO NORMAL SCHOOL YEARS, (3) EACH PROBATIONARY EMPLOYEE IS TO RECEIVE REGULAR EVALUATION REPORTS AND IS TO HAVE A CHANCE TO…

LEAHY, MARY LEE

472

78 FR 28895 - Sunshine Act Meetings  

Federal Register 2010, 2011, 2012, 2013, 2014

...for her service on the Pro Bono Task Force (Resolution 2013-XXX) 4. Consider and act on whether to authorize an executive session...General Counsel, and Corporate Secretary (Resolution 2013-XXX) 7. Public comment 8. Consider and act on other business...

2013-05-16

473

77 FR 52066 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013, 2014

...request for FY 2014 (Resolution 2012-XXX) 4. Consider and act on the Strategic...for Grants Management (Resolution 2012-XXX) 6. Consider and act on whether to authorize...for Grants Management (Resolution 2012-XXX) 9. Public comment 10. Consider and...

2012-08-28

474

Acts of Reading: Teachers, Text and Childhood  

ERIC Educational Resources Information Center

"Acts of Reading" is an enchanting and scholarly review of the history of reading and texts for children, from the 18th century to the digital age and beyond. They are examined through the eyes of their various audiences: the children, writers, teachers and parents, so as to explore the act of reading itself, whether oral, silent or performative,…

Styles, Morag, Ed.; Arizpe, Evelyn, Ed.

2009-01-01

475

Mark S. Paese (Acting) Assistant Administrator for  

E-print Network

Commercial Remote Sensing Regulatory Affairs Office Mark S. Paese (Acting) OfficeofSpace Commercialization Applications and Research Suzanne Hilding Office of Systems Development Gregory Mandt GOES-R Program Office Deputy Assistant Administrator, Systems KellyTurner Chief of Staff Vanessa Griffin (Acting) Assistant

476

The homicide, the pervert act and paternity  

Microsoft Academic Search

Proposition to articulate perverse subjectivity and the pervert act was established, wherein, the dynamics of criminal acts, as means of lust, and convicts' positioning within social bonds configure the outlines. For this purpose, imprisoned were registered in unit of Rio de Janeiro Penal System was interviewed. The concept of perversion was a starting point and means for interpretation of the

Francisco Ramos de Farias

2009-01-01

477

Illinois Abused and Neglected Child Reporting Act  

E-print Network

Illinois Abused and Neglected Child Reporting Act Illinois law related to the reporting of suspected child abuse or neglect. Outlines a variety of persons who are considered "mandatory reporters #12;Illinois Abused and Neglected Child Reporting Act As a mandatory reporter, you are required

Nickrent, Daniel L.

478

Data Protection Act 1998 Guidance for  

E-print Network

Data Protection Act 1998 ­ Guidance for Staff/Students v1.0 v1.0 June 2012 Elaine Forbes, registered in Scotland, number SC015263 #12;Data Protection Act 1998 ­ Guidance for Staff/Students v1.0 Page .................................................................................................... 2 2. Personal Data in the University

Mottram, Nigel

479

Attachment A Clery Act Reportable Crimes / Definitions  

E-print Network

through gross negligence. Sex Offense (Forcible) Any sexual act directed against another person without for the purpose of sexual gratification.) Sex Offense (Non-forcible) Any unlawful, but consensual sex act with another person. (Includes attempts) A. Incest (sexual intercourse between persons who are related to one

Shahriar, Selim

480

Functional Diversity of Carbohydrate-Active Enzymes Enabling a Bacterium to Ferment Plant Biomass  

PubMed Central

Microbial metabolism of plant polysaccharides is an important part of environmental carbon cycling, human nutrition, and industrial processes based on cellulosic bioconversion. Here we demonstrate a broadly applicable method to analyze how microbes catabolize plant polysaccharides that integrates carbohydrate-active enzyme (CAZyme) assays, RNA sequencing (RNA-seq), and anaerobic growth screening. We apply this method to study how the bacterium Clostridium phytofermentans ferments plant biomass components including glucans, mannans, xylans, galactans, pectins, and arabinans. These polysaccharides are fermented with variable efficiencies, and diauxies prioritize metabolism of preferred substrates. Strand-specific RNA-seq reveals how this bacterium responds to polysaccharides by up-regulating specific groups of CAZymes, transporters, and enzymes to metabolize the constituent sugars. Fifty-six up-regulated CAZymes were purified, and their activities show most polysaccharides are degraded by multiple enzymes, often from the same family, but with divergent rates, specificities, and cellular localizations. CAZymes were then tested in combination to identify synergies between enzymes acting on the same substrate with different catalytic mechanisms. We discuss how these results advance our understanding of how microbes degrade and metabolize plant biomass. PMID:25393313

Boutard, Magali; Cerisy, Tristan; Nogue, Pierre-Yves; Alberti, Adriana; Weissenbach, Jean; Salanoubat, Marcel; Tolonen, Andrew C.

2014-01-01

481

Roles of lipid-modulating enzymes diacylglycerol kinase and cyclooxygenase under pathophysiological conditions.  

PubMed

Lipid not only represents a constituent of the plasma membrane, but also plays a pivotal role in intracellular signaling. Lipid-mediated signaling system is strictly regulated by several enzymes, which act at various steps of the lipid metabolism. Under pathological conditions, prolonged or insufficient activation of this system results in dysregulated signaling, leading to diseases such as cancer or metabolic syndrome. Of the lipid-modulating enzymes, diacylglycerol kinase (DGK) and cyclooxygenase (COX) are intimately involved in the signaling system. DGK consists of a family of enzymes that phosphorylate a second messenger diacylglycerol (DG) to produce phosphatidic acid (PA). Both DG and PA are known to activate signaling molecules such as protein kinase C. COX catalyzes the committed step in prostanoid biosynthesis, which involves the metabolism of arachidonic acid to produce prostaglandins. Previous studies have shown that the DGK and COX are engaged in a number of pathological conditions. This review summarizes the functional implications of these two enzymes in ischemia, liver regeneration, vascular events, diabetes, cancer and inflammation. PMID:25471593

Nakano, Tomoyuki

2015-01-01

482

Characterization of an extracellular enzyme system produced by Micromonospora chalcea with lytic activity on yeast cells.  

PubMed

Growth of Micromonospora chalcea on a defined medium containing laminarin as the sole carbon source induced the production of an extracellular enzyme system capable of lysing cells of various yeast species. Production of the lytic enzyme system was repressed by glucose. Incubation of sensitive cells with the active component enzymes of the lytic system produced protoplasts in high yield. Analysis of the enzyme composition indicated that beta(1-->3) glucanase and protease were the most prominent hydrolytic activities present in the culture fluids. The system also displayed weak chitinase and beta(1-->6) glucanase activities whilst devoid of mannanase activity. Our observations suggest that the glucan supporting the cell wall framework of susceptible yeast cells is not directly accessible to the purified endo-beta(1-->3) glucanase and that external proteinaceous components prevent breakdown of this polymer in whole cells. We propose that protease acts in synergy with beta(1-->3) glucanase and that the primary action of the former on surface components allows subsequent solubilization of inner glucan leading to lysis. PMID:10849171

Gacto, M; Vicente-Soler, J; Cansado, J; Villa, T G

2000-06-01

483

STUDY OF ARACHIDONOYL SPECIFICITY IN TWO ENZYMES OF THE PI-CYCLE  

PubMed Central

We identified a conserved pattern of residues L-X(3–4)-R-X(2)-L-X(4)-G, in which -X(n)- represents n residues of any amino acids, in two enzymes acting on polyunsaturated fatty acids, diacylglycerol kinase epsilon (DGK?) and phosphatidylinositol-4-phosphate-5-kinase I? (PIP5K I?). DGK? is the only one of the 10 mammalian isoforms of DGK that exhibits arachidonoyl specificity and is the only isoform with the aforementioned motif. Mutations of the essential residues in this motif result in loss of arachidonoyl specificity. Furthermore, DGK? can be converted to an enzyme having this motif by substituting only one residue. When DGK? was mutated so that it gained the motif, the enzyme also gained some specificity for arachidonoyl-containing diacylglycerol. This motif is also present in an isoform of phosphatidylinositol-4-phosphate-5-kinase that we demonstrated had arachidonoyl-specificity for its substrate. Single residue mutations within the identified motif of this isoform result in loss of activity against an arachidonoyl substrate. The importance of acyl chain specificity for the phosphatidic acid activation of phosphatidylinositol-4-phosphate-5-kinase is also shown. We also demonstrate that the acyl chain dependence of this phosphatidic acid activation is dependent on the substrate. This is the first demonstration of a motif that endows specificity for an acyl chain in two studied enzymes, DGK? and PIP5K I?. PMID:21477596

Shulga, Yulia V.; Topham, Matthew K.; Epand, Richard M.

2011-01-01

484

A new dopachrome-rearranging enzyme from the ejected ink of the cuttlefish Sepia officinalis.  

PubMed Central

A melanogenic enzyme catalysing the rearrangement of dopachrome has been identified in the ejected ink of the cuttlefish Sepia officinalis. This enzyme occurs as a heat-labile protein which co-migrates with tyrosinase under a variety of chromatographic and electrophoretic conditions. On SDS/PAGE it shows like a single band with an approx. molecular mass of 85 kDa. The enzyme possesses high substrate specificity, acting on L-dopachrome (Km = 1 mM at pH 6.8) and on L-alpha-methyl-dopachrome, but not on D-dopachrome, L-dopachrome methyl ester, dopaminochrome and adrenochrome. Significant inhibition of the catalytic activity was observed with tropolone and L-mimosine. H.p.1.c. analysis of the enzyme-catalysed rearrangement of L-dopachrome revealed the quantitative formation of the decarboxylated product, 5,6-dihydroxyindole. These results point to marked differences between melanogenesis in cephalopod pigment cells and in melanocytes, which may have important implications in relation to the use of sepiomelanin as a model for studies of mammalian melanins. Images Figure 2 PMID:8192674

Palumbo, A; d'Ischia, M; Misuraca, G; De Martino, L; Prota, G

1994-01-01

485

76 FR 64112 - Privacy Act of 1974; Privacy Act System of Records Appendices  

Federal Register 2010, 2011, 2012, 2013, 2014

...1974; Privacy Act System of Records Appendices AGENCY: National Aeronautics and Space...NASA). ACTION: Revisions of NASA Appendices to Privacy Act System of Records...given that NASA is amending the standard appendices that it regularly publishes with...

2011-10-17

486

Malic Enzyme and Malolactic Enzyme Pathways Are Functionally Linked but Independently Regulated in Lactobacillus casei BL23  

PubMed Central

Lactobacillus casei is the only lactic acid bacterium in which two pathways for l-malate degradation have been described: the malolactic enzyme (MLE) and the malic enzyme (ME) pathways. Whereas the ME pathway enables L. casei to grow on l-malate, MLE does not support growth. The mle gene cluster consists of three genes encoding MLE (mleS), the putative l-malate transporter MleT, and the putative regulator MleR. The mae gene cluster consists of four genes encoding ME (maeE), the putative transporter MaeP, and the two-component system MaeKR. Since both pathways compete for the same substrate, we sought to determine whether they are coordinately regulated and their role in l-malate utilization as a carbon source. Transcriptional analyses revealed that the mle and mae genes are independently regulated and showed that MleR acts as an activator and requires internalization of l-malate to induce the expression of mle genes. Notwithstanding, both l-malate transporters were required for maximal l-malate uptake, although only an mleT mutation caused a growth defect on l-malate, indicating its crucial role in l-malate metabolism. However, inactivation of MLE resulted in higher growth rates and higher final optical densities on l-malate. The limited growth on l-malate of the wild-type strain was correlated to a rapid degradation of the available l-malate to l-lactate, which cannot be further metabolized. Taken together, our results indicate that L. casei l-malate metabolism is not optimized for utilization of l-malate as a carbon source but for deacidification of the medium by conversion of l-malate into l-lactate via MLE. PMID:23835171

Landete, José María; Ferrer, Sergi; Monedero, Vicente

2013-01-01

487

Malic enzyme and malolactic enzyme pathways are functionally linked but independently regulated in Lactobacillus casei BL23.  

PubMed

Lactobacillus casei is the only lactic acid bacterium in which two pathways for l-malate degradation have been described: the malolactic enzyme (MLE) and the malic enzyme (ME) pathways. Whereas the ME pathway enables L. casei to grow on l-malate, MLE does not support growth. The mle gene cluster consists of three genes encoding MLE (mleS), the putative l-malate transporter MleT, and the putative regulator MleR. The mae gene cluster consists of four genes encoding ME (maeE), the putative transporter MaeP, and the two-component system MaeKR. Since both pathways compete for the same substrate, we sought to determine whether they are coordinately regulated and their role in l-malate utilization as a carbon source. Transcriptional analyses revealed that the mle and mae genes are independently regulated and showed that MleR acts as an activator and requires internalization of l-malate to induce the expression of mle genes. Notwithstanding, both l-malate transporters were required for maximal l-malate uptake, although only an mleT mutation caused a growth defect on l-malate, indicating its crucial role in l-malate metabolism. However, inactivation of MLE resulted in higher growth rates and higher final optical densities on l-malate. The limited growth on l-malate of the wild-type strain was correlated to a rapid degradation of the available l-malate to l-lactate, which cannot be further metabolized. Taken together, our results indicate that L. casei l-malate metabolism is not optimized for utilization of l-malate as a carbon source but for deacidification of the medium by conversion of l-malate into l-lactate via MLE. PMID:23835171

Landete, José María; Ferrer, Sergi; Monedero, Vicente; Zúñiga, Manuel

2013-09-01

488

Purification and characterization of a novel thermostable 4-alpha-glucanotransferase of Thermotoga maritima cloned in Escherichia coli.  

PubMed

Maltodextrin glycosyltransferase (4-alpha-glucanotransferase) of the extremely thermophilic ancestral bacterium Thermotoga maritima has been purified from an Escherichia coli clone expressing the corresponding T. maritima MSB8 chromosomal gene. T. maritima 4-alpha-glucanotransferase, an approximately 53-kDa monomeric enzyme, is the most thermophilic glycosyltransferase described to date. It retained more than 90% of its maximum activity at temperatures from 55 degrees C up to 80 degrees C. The proposed action modus is the transfer of 1,4-alpha-glucanosyl chains, thus resulting in the disproportionation of 1,4-alpha-glucans. It converted soluble starch, amylopectin, and amylose, thereby changing the iodine staining properties of these substrates. The addition of low-molecular-mass malto-oligosaccharides, which act as glucanosyl acceptor molecules, enhanced the reaction and resulted in the formation of a series of linear maltohomologues from two to more than nine glucose units in size. Use of either of the malto-oligosaccharides maltotetraose, maltopentaose, maltohexaose, or maltoheptaose as sole substrate also yielded linear maltohomologues. On the other hand, maltose and maltotriose were not disproportionated by 4-alpha-glucanotransferase, although both were good acceptors for glucanosyl transfer. Glucose did not function as an acceptor in transfer reactions. Glucose also never appeared as a reaction product. The chain length of glucanosyl segments transferred ranged from two to probably far more than six glucose residues. Comparison of the N-terminal amino acid sequence of 4-alpha-glucanotransferase with other published protein sequences revealed significant similarity to sequences near the N-termini of various eucaryotic maltases and bacterial cyclodextrin glycosyltransferases, suggesting its relatedness on the molecular level with other starch- and maltodextrin-converting enzymes. PMID:1628664

Liebl, W; Feil, R; Gabelsberger, J; Kellermann, J; Schleifer, K H

1992-07-01

489

Inside the trap: gland morphologies, digestive enzymes, and the evolution of plant carnivory in the Caryophyllales?  

PubMed Central

The digestion of prey by carnivorous plants is determined in part by suites of enzymes that are associated with morphologically and anatomically diverse trapping mechanisms. Chitinases represent a group of enzymes known to be integral to effective plant carnivory. In non-carnivorous plants, chitinases commonly act as pathogenesis-related proteins, which are either induced in response to insect herbivory and fungal elicitors, or constitutively expressed in tissues vulnerable to attack. In the Caryophyllales carnivorous plant lineage, multiple classes of chitinases are likely involved in both pathogenic response and digestion of prey items. We review what is currently known about trap morphologies, provide an examination of the diversity, roles, and evolution of chitinases, and examine how herbivore and pathogen defense mechanisms may have been coopted for plant carnivory in the Caryophyllales. PMID:23830995

Renner, Tanya; Specht, Chelsea D

2013-01-01

490

Multigenerational chromatin marks: no enzymes need apply.  

PubMed

Epigenetic memory stably maintains and transmits information during genome replication. Recently in Science, Gaydos et al. (2014) show that repressive chromatin marks exhibit transgenerational stability in the absence of chromatin-modifying enzymes in Caenorhabditis elegans, in contrast to work in flies suggesting that such proteins mediate stable inheritance of epigenetic modifications. PMID:25373774

Kelly, William G

2014-10-27

491

Dynamics of Radical-Mediated Enzyme Catalyses  

NASA Astrophysics Data System (ADS)

An emergent class of enzymes harnesses the extreme reactivity of electron-deficient free radical species to perform some of the most difficult reactions in biology. The regio- and stereo-selectivity achieved by these enzymes defies long-held ideas that radical reactions are non-specific. The common primary step in these catalyses is metal- or metallocenter-assisted generation of an electron-deficient organic "initiator radical". The initiator radical abstracts a hydrogen atom from the substrate, opening a new reaction channel for rearrangement to the product. Our aim is to elucidate the detailed molecular mechanisms of the radical pair separation and radical rearrangement steps. Radical pair separation and substrate radical rearrangement are tracked by using time-resolved (10-7 to 10-3 s) techniques of pulsed-electron paramagnetic resonance spectroscopy (FT-EPR, ESEEM). Synchronous time-evolution of the reactions is attained by triggering with a visible laser pulse. Transient non-Boltzmann population of the states of the spin-coupled systems, and resultant electron spin polarization, facilitates study at or near room temperature under conditions where the enzymes are operative. The systems examined include ethanolamine deaminase, a vitamin B12 coenzyme-dependent enzyme, ribonucleotide reductase and photosynthetic reaction centers. The electronic and nuclear structural and kinetic information obtained from the pulsed-EPR studies is used to address how the initiator radicals are stabilized against deleterious recombination with the metal, and to distinguish the participation of concerted versus sequential rearrangement pathways.

Warncke, Kurt

1997-11-01

492

Stabilization of Enzymes in Silk Films  

PubMed Central

Material systems are needed that promote stabilization of entrained molecules, such as enzymes or therapeutic proteins, without destroying their activity. We demonstrate that the unique structure of silk fibroin protein, when assembled into the solid state, establishes an environment that is conducive to the stabilization of entrained proteins. Enzymes (glucose oxidase, lipase and horseradish peroxidase) entrapped in these films over ten months retained significant activity, even when stored at 37°C, and in the case of glucose oxidase did not lose any activity. Further, the mode of processing of the silk protein into the films could be correlated to the stability of the enzymes. The relationship between processing and stability offers a large suite of conditions within which to optimize such stabilization processes. Overall, the techniques reported here result in materials that stabilize enzymes to a remarkable extent, without the need for cryoprotectants, emulsifiers, covalent immobilization or other treatments. Further, these systems are amenable to optical characterization, environmental distribution without refrigeration, are ingestible, and offer potential use in vivo, since silk materials are biocompatible and FDA approved, degradable with proteases and currently used in biomedical devices. PMID:19323497

Lu, Shenzhou; Wang, Xiaoqin; Lv, Qiang; Hu, Xiao; Uppal, Neha; Omenetto, Fiorenzo

2009-01-01

493

Hyaluronidases--a group of neglected enzymes.  

PubMed Central

Hyaluronan is an important constituent of the extracellular matrix. This polysaccharide can be hydrolyzed by various hyaluronidases that are widely distributed in nature. The structure of some bacterial and animal enzymes of this type has recently been elucidated. It could be shown that the hyaluronidases from bee and hornet venom and the PH-20 hyaluronidase present on mammalian spermatozoa are homologous proteins. PMID:8528065

Kreil, G.

1995-01-01

494

Investigating Degradation Enzymes for Pentachlorophenols (PCPs)  

E-print Network

is still lacking. This study aims to solve the crystal structure of PcpC, which is an enzyme in the pathway, which are homologs of PcpC, which have mutations at the number 14 Cysteine and number 157 Cysteine respectively. The cysteines have been replaced with Serine so that the sulfur in cysteines won't interfere

Collins, Gary S.

495

Artificial concurrent catalytic processes involving enzymes.  

PubMed

The concurrent operation of multiple catalysts can lead to enhanced reaction features including (i) simultaneous linear multi-step transformations in a single reaction flask (ii) the control of intermediate equilibria (iii) stereoconvergent transformations (iv) rapid processing of labile reaction products. Enzymes occupy a prominent position for the development of such processes, due to their high potential compatibility with other biocatalysts. Genes for different enzymes can be co-expressed to reconstruct natural or construct artificial pathways and applied in the form of engineered whole cell biocatalysts to carry out complex transformations or, alternatively, the enzymes can be combined in vitro after isolation. Moreover, enzyme variants provide a wider substrate scope for a given reaction and often display altered selectivities and specificities. Man-made transition metal catalysts and engineered or artificial metalloenzymes also widen the range of reactivities and catalysed reactions that are potentially employable. Cascades for simultaneous cofactor or co-substrate regeneration or co-product removal are now firmly established. Many applications of more ambitious concurrent cascade catalysis are only just beginning to appear in the literature. The current review presents some of the most recent examples, with an emphasis on the combination of transition metal with enzymatic catalysis and aims to encourage researchers to contribute to this emerging field. PMID:25350691

Köhler, Valentin; Turner, Nicholas J

2015-01-11

496

Engineering an enzyme to resist boiling  

PubMed Central

In recent years, many efforts have been made to isolate enzymes from extremophilic organisms in the hope to unravel the structural basis for hyperstability and to obtain hyperstable biocatalysts. Here we show how a moderately stable enzyme (a thermolysin-like protease from Bacillus stearothermophilus, TLP-ste) can be made hyperstable by a limited number of mutations. The mutational strategy included replacing residues in TLP-ste by residues found at equivalent positions in naturally occurring, more thermostable variants, as well as rationally designed mutations. Thus, an extremely stable 8-fold mutant enzyme was obtained that was able to function at 100°C and in the presence of denaturing agents. This 8-fold mutant contained a relatively large number of mutations whose stabilizing effect is generally considered to result from a reduction of the entropy of the unfolded state (“rigidifying” mutations such as Gly ? Ala, Ala ? Pro, and the introduction of a disulfide bridge). Remarkably, whereas hyperstable enzymes isolated from natural sources often have reduced activity at low temperatures, the 8-fold mutant displayed wild-type-like activity at 37°C. PMID:9482837

Van den Burg, Bertus; Vriend, Gert; Veltman, Oene R.; Venema, Gerard; Eijsink, Vincent G. H.

1998-01-01

497

Chapter 2 Enzymes of saprotrophic basidiomycetes  

Microsoft Academic Search

Decomposer fungi utilize dead organic matter that is mainly composed of cell wall polysaccharides and other biopolymers. These include cell wall polymers of plant origin (cellulose, hemicelluloses, lignin, pectin), cell wall polysaccharides of fungi (chitin) and nutrient reserve polysaccharide (starch) as well as proteins. Utilization of these polymers necessitates production of extracellular enzymes; the polysaccharide-based biopolymers are usually degraded by

Petr Baldrian

2008-01-01

498

Ferredoxin-linked chloroplast enzymes. Progress report  

SciTech Connect

This report summarizes research on ferredoxin:NADP{sup +} oxidoreductase and ferredoxin:thioredoxin reductase. One of the primary goals of the original proposal was to map the ferredoxin-binding sites on three soluble enzymes that are located in spinach chloroplasts and utilize ferredoxin as an electron donor:Ferredoxin:NADP{sup +} oxidoreductase (FNR); ferredoxin:thioredoxin reductase (FTR) and glutamate synthase. As the availability of amino acid sequences for the enzymes are important in such studies, it was proposed that the amino acid sequence of glutamate synthase be determined. The amino acid sequences of FNR, FTR and ferredoxin are already known. An aim related to elucidating the binding sites on these enzymes for ferredoxin was to determine whether there is a common site on ferredoxin involved in binding to all of these ferredoxin-dependent chloroplast enzymes and, if so, to map it. One additional aim was to characterize thioredoxin binding by FTR and determine whether the same site on FTR is involved in binding both ferredoxin and thioredoxin. Considerable progress has been made on most of these original projects, although work conducted on FTR is still in its preliminary stages.

NONE

1993-12-31

499

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

500

Rapid purification of fluorescent enzymes by ultrafiltration  

NASA Technical Reports Server (NTRS)

In order to expedite the preparation of fluorescently tagged enzymes for histo-cyctochemistry, a previously developed method employing gel column purification was compared with a more rapid modern technique using the Millipore Immersible CX-ultrafilter. Microscopic evaluation of the resulting conjugates showed comparable products. Much time and effort is saved using the new technique.

Benjaminson, M. A.; Satyanarayana, T.

1983-01-01