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1

[Degradation of Maillard reaction products by amylolytic enzymes. 2. Enzymatic degradation of heat-treated alpha-glucans with and without amino compounds].  

PubMed

The enzymatic degradation of thermal treated alpha-glucans with amylolytic enzymes depends on the reaction environment (T, pH, moisture), the degree of polymerisation (DP) and the branch of the substrates as well as on the presence of amino compounds. The chemical changes of the alpha-glucans due to thermolysis at 180 degrees C are characterized by means of the amount of reducing substances and the amount of maltooligosaccharides (HPLC). In general the enzymatic degradability of the thermal treated alpha-glucans is decreased with increasing time of thermolysis, temperature and moisture content. The enzyme activity with the thermal treated alpha-glucans is diminished in the same way. The addition of amino compounds reduces the enzymatic degradability only at the beginning of the reaction. With increasing time of thermolysis the thermolysates without glycine addition are hardly degraded. As reason for these differences in the enzymatic degradation transglycosylation and non-enzymatic browning reactions (caramalisation/Maillard-reaction) are assumed. PMID:9123977

Kroh, L W; Schumacher, D

1996-10-01

2

Alpha-glucan, water dikinase (GWD): a plastidic enzyme with redox-regulated and coordinated catalytic activity and binding affinity.  

PubMed

The recently discovered potato tuber (Solanum tuberosum) alpha-glucan, water dikinase (GWD) (formerly known as R1) catalyzes the phosphorylation of starch by a dikinase-type reaction mechanism in which the beta-phosphate of ATP is transferred to either the C-6 or the C-3 position of the glucosyl residue of starch. In the present study, we found that the GWD enzyme is inactive in the oxidized form, which is accompanied by the formation of a specific intramolecular disulfide bond as determined by disulfide-linked peptide mapping. The regulatory properties of this disulfide linkage were confirmed by site-directed mutagenesis studies. Both reduced thioredoxin (Trx) f and Trx m from spinach leaves reduced and activated oxidized GWD at very low concentrations, with Trx f being the more efficient, yielding an S0.5 value of 0.4 microM. Interestingly, GWD displays a reversible and selective binding to starch granules depending on the illumination state of the plant. Here we show that starch granule-bound GWD isolated from dark-adapted plants exists in the inactive, oxidized form, which is capable of reactivation upon treatment with reduced Trx. Furthermore, the soluble form of GWD was found in its fully reduced state, providing evidence of a Trx-controlled regulation mechanism linking enzymatic activity and specific binding affinities of a protein to an intracellular surface. The regulatory site sequence, CFATC, of potato GWD is conserved in chloroplast-targeted GWDs from other species, suggesting an overall redox regulation of the GWD enzyme. PMID:15665090

Mikkelsen, René; Mutenda, Kudzai E; Mant, Alexandra; Schürmann, Peter; Blennow, Andreas

2005-02-01

3

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

4

The structure of cell wall alpha-glucan from fission yeast.  

PubMed

Morphology and structural integrity of fungal cells depend on cell wall polysaccharides. The chemical structure and biosynthesis of two types of these polysaccharides, chitin and (1-->3)-beta-glucan, have been studied extensively, whereas little is known about alpha-glucan. Here we describe the chemical structure of alpha-glucan isolated from wild-type and mutant cell walls of the fission yeast Schizosaccharomyces pombe. Wild-type alpha-glucan was found to consist of a single population of linear glucose polymers, approximately 260 residues in length. These glucose polymers were composed of two interconnected linear chains, each consisting of approximately 120 (1-->3)-linked alpha-d-glucose residues and some (1-->4)-linked alpha-D-glucose residues at the reducing end. By contrast, alpha-glucan of an alpha-glucan synthase mutant with an aberrant cell morphology and reduced alpha-glucan levels consisted of a single chain only. We propose that alpha-glucan biosynthesis involves an ordered series of events, whereby two alpha-glucan chains are coupled to create mature cell wall alpha-glucan. This mature form of cell wall alpha-glucan is essential for fission-yeast morphogenesis. PMID:15470229

Grün, Christian H; Hochstenbach, Frans; Humbel, Bruno M; Verkleij, Arie J; Sietsma, J Hans; Klis, Frans M; Kamerling, Johannis P; Vliegenthart, Johannes F G

2005-03-01

5

Variation in storage alpha-glucans of the Porphyridiales (Rhodophyta).  

PubMed

Storage glucans were analyzed in the Porphyridiales which include the most primitive and phylogenetically diverged species in the Rhodophyta, to understand early evolution of the glucan structure in the Rhodophyta. The storage glucans of both Galdieria sulphuraria and Cyanidium caldarium consisted of glycogen, while those of Rhodosorus marinus, Porphyridium purpureum, P. sordidum and Rhodella violacea could be defined as semi-amylopectin. X-ray diffraction analysis of the glucans demonstrated variation in the crystalline structure: the patterns in P. purpureum and R. violacea were of A- and B-types, respectively, while alpha-glucans of R. marinus and P. sordidum displayed structures with lower crystallinity. Electron microscopic observations indicated that the alpha-glucans of P. sordidum consisted of two kinds of granules; a minor component of more dense granules with crystalline leaflets and a major component of softer ones without crystalline structure. Gel permeation chromatography showed that all the species containing the semi-amylopectin-type glucans also contained amylose, although the relative amounts of this fraction were different depending on the species. Our results are consistent with two distinct evolution scenarios defined either by the independent acquisition of semi-crystalline starch-like structures in the different plant lineages or more probably by the loss of starch and reversion to glycogen synthesis in cyanidian algae growing in hot and acid environments. PMID:18079144

Shimonaga, Takahiro; Konishi, Mai; Oyama, Yasunori; Fujiwara, Shoko; Satoh, Aya; Fujita, Naoko; Colleoni, Christophe; Buléon, Alain; Putaux, Jean-Luc; Ball, Steven G; Yokoyama, Akiko; Hara, Yoshiaki; Nakamura, Yasunori; Tsuzuki, Mikio

2008-01-01

6

Identification of a putative alpha-glucan synthase essential for cell wall construction and morphogenesis in fission yeast  

PubMed Central

The cell wall protects fungi against lysis and determines their cell shape. Alpha-glucan is a major carbohydrate component of the fungal cell wall, but its function is unknown and its synthase has remained elusive. Here, we describe a fission yeast gene, ags1+, which encodes a putative alpha-glucan synthase. In contrast to the structure of other carbohydrate polymer synthases, the predicted Ags1 protein consists of two probable catalytic domains for alpha-glucan assembly, namely an intracellular domain for alpha-glucan synthesis and an extracellular domain speculated to cross-link or remodel alpha-glucan. In addition, the predicted Ags1 protein contains a multipass transmembrane domain that might contribute to transport of alpha-glucan across the membrane. Loss of Ags1p function in a temperature-sensitive mutant results in cell lysis, whereas mutant cells grown at the semipermissive temperature contain decreased levels of cell wall alpha-glucan and fail to maintain rod shapes, causing rounding of the cells. These findings demonstrate that alpha-glucan is essential for fission yeast morphogenesis.

Hochstenbach, Frans; Klis, Frans M.; van den Ende, Herman; van Donselaar, Elly; Peters, Peter J.; Klausner, Richard D.

1998-01-01

7

The Structural Basis of Alpha-Glucan Recognition by a Family 41 Carbohydrate-Binding Module from Therotoga Maritima  

SciTech Connect

Starch recognition by carbohydrate-binding modules (CBMs) is important for the activity of starch-degrading enzymes. The N-terminal family 41 CBM, TmCBM41 (from pullulanase PulA secreted by Thermotoga maritima) was shown to have {alpha}-glucan binding activity with specificity for {alpha}-1, 4-glucans but was able to tolerate the {alpha}-1, 6-linkages found roughly every three or four glucose units in pullulan. Using X-ray crystallography, the structures were solved for TmCBM41 in an uncomplexed form and in complex with maltotetraose and 63-{alpha}-d-glucosyl-maltotriose (GM3). Ligand binding was facilitated by stacking interactions between the {alpha}-faces of the glucose residues and two tryptophan side-chains in the two main subsites of the carbohydrate-binding site. Overall, this mode of starch binding is quite well conserved by other starch-binding modules. The structure in complex with GM3 revealed a third binding subsite with the flexibility to accommodate an {alpha}-1, 4- or an {alpha}-1, 6-linked glucose.

van Bueren,A.; Boraston, A.

2006-01-01

8

Anti-diabetic effect of an alpha-glucan from fruit body of maitake (Grifola frondosa) on KK-Ay mice.  

PubMed

We have evaluated the anti-diabetic effect of a alpha-glucan (MT-alpha-glucan) from the fruit body of maitake mushrooms (Grifola frondosa) on KK-Ay mice (a kind of genetical type 2 diabetes animal model). The effects of MT-alpha-glucan (450 or 150 mg kg (-1)) on diabetic mice were investigated by observing the changes in body weight, the level of fasting plasma glucose, glycosylated serum protein (GSP), hepatic glycogen, serum insulin, triglycerides, cholesterol, free fatty acid, liver superoxide dismutase (SOD), glutathione peroxidase (GSHpx), reduced glutathione (GSH) and malondialdehyde (MDA). Moreover, the binding capacity of insulin receptors on liver crude plasma membranes was assayed and histopathological changes in the pancreas were observed. Treatment with MT-alpha-glucan significantly decreased the body weight, level of fasting plasma glucose, GSP, serum insulin, triglycerides, cholesterol, free fatty acid and MDA content in livers. Treatment with MT-alpha-glucan significantly increased the content of hepatic glycogen, GSH and the activity of SOD and GSHpx. Moreover, the insulin binding capacity to liver crude plasma membranes increased and histopathological changes in the pancreas were ameliorated in the treatment group. These data suggest that MT-alpha-glucan has an anti-diabetic effect on KK-Ay mice, which might be related to its effect on insulin receptors (i.e., increasing insulin sensitivity and ameliorating insulin resistance of peripheral target tissues). PMID:17430642

Hong, Lei; Xun, Ma; Wutong, Wu

2007-04-01

9

Maize branching enzyme catalyzes synthesis of glycogen-like polysaccharide in glgB-deficient Escherichia coli.  

PubMed Central

The structure of alpha-glucan, isolated from wild-type Escherichia coli B, a glycogen branching enzyme (BE)-deficient E. coli AC71 (glgB-), or from AC71 transformed with genes coding for maize BEI and BEII individually as well as with both genes, was analyzed by high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection. Transformation of the maize BE gene(s) in AC71 (glgB-) showed complementation in branching activity. Analysis by HPAEC revealed different structures between glycogen of E. coli B and alpha-glucan of AC71 transformed with a different maize BE gene(s). The individual chains of the alpha-glucan debranched with isoamylase were distributed between chain length (CL) 3 and > 30 and the chain with CL 6 was the most abundant. In comparison with the glycogen of E. coli B, the alpha-glucan of AC71 transformed with the maize BE gene(s) consisted of a lesser amount of chains with CL 7-9 and a larger amount of chains with CL > 14. It also showed a broad peak with chains of CL 9-12 as in maize amylopectin. This study provides in vivo evidence that glycogen BE and maize BE isozymes may have different specificities in the length of chain transferred. Furthermore, this study suggests that the specificity of glycogen synthase and starch synthase and their concerted action with BE play an important role in determining the structure of the polysaccharide synthesized.

Guan, H; Kuriki, T; Sivak, M; Preiss, J

1995-01-01

10

The primitive rhodophyte Cyanidioschyzon merolae contains a semiamylopectin-type, but not an amylose-type, alpha-glucan.  

PubMed

The storage glucans of Cyanidioschyzon merolae [clade L-1 (cyanidian algae), order Porphyridiales, subclass Bangiophycidae], which is considered to be one of the most primitive rhodophytes, were analyzed to understand the early evolution of the glucan structure in the Rhodophyta. Chain-length distribution analysis of the glucans of cyanidian algae demonstrated that while the glucans of Cyanidium caldarium and Galdieria sulphuraria are of the glycogen type, those of C. merolae are of the semiamylopectin type, as in other lineages of the Rhodophyta. Gel permeation chromatography, however, showed that the glucans of C. merolae do not include amylose, being different from those of other Bangiophycidae species. Identification by MALDI-TOF-MS and enzyme assaying of glucan granule-bound proteins indicated that phosphorylase, but not starch synthase, is included. Thus, C. merolae has an unusual glucan and bound-protein composition for the Bangiophycidae, appearing to be a member of the Florideophycidae. The finding that the alga does not contain amylose or the related enzyme, granule-bound starch synthase, is, however, consistent with previously reported results of molecular phylogenetic analysis of starch synthases. Our results support an evolutionary scenario defined by the loss of starch and reversion to glycogen synthesis during the evolution of cyanidian algae, and suggest the possibility that a C. merolae-like primitive rhodophyte might have evolved into the Florideophycidae. PMID:20385610

Hirabaru, Chika; Izumo, Asako; Fujiwara, Shoko; Tadokoro, Yukie; Shimonaga, Takahiro; Konishi, Mai; Yoshida, Mayumi; Fujita, Naoko; Nakamura, Yasunori; Yoshida, Masaki; Kuroiwa, Tsuneyoshi; Tsuzuki, Mikio

2010-05-01

11

Water and a protic ionic liquid acted as refolding additives for chemically denatured enzymes.  

PubMed

In this communication, we present the ability of water and a protic ionic liquid, triethyl ammonium phosphate (TEAP) to act as refolding additives for the urea-induced chemical denaturated state of the two enzymes, ?-chymotrypsin and succinylated Con A. We show that the enzymatic activity is regained and in certain circumstances enhanced. PMID:22814381

Attri, Pankaj; Venkatesu, P; Kumar, Anil

2012-10-01

12

Maize branching enzyme catalyzes synthesis of glycogen-like polysaccharide in glgB-deficient Escherichia coli.  

PubMed

The structure of alpha-glucan, isolated from wild-type Escherichia coli B, a glycogen branching enzyme (BE)-deficient E. coli AC71 (glgB-), or from AC71 transformed with genes coding for maize BEI and BEII individually as well as with both genes, was analyzed by high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection. Transformation of the maize BE gene(s) in AC71 (glgB-) showed complementation in branching activity. Analysis by HPAEC revealed different structures between glycogen of E. coli B and alpha-glucan of AC71 transformed with a different maize BE gene(s). The individual chains of the alpha-glucan debranched with isoamylase were distributed between chain length (CL) 3 and > 30 and the chain with CL 6 was the most abundant. In comparison with the glycogen of E. coli B, the alpha-glucan of AC71 transformed with the maize BE gene(s) consisted of a lesser amount of chains with CL 7-9 and a larger amount of chains with CL > 14. It also showed a broad peak with chains of CL 9-12 as in maize amylopectin. This study provides in vivo evidence that glycogen BE and maize BE isozymes may have different specificities in the length of chain transferred. Furthermore, this study suggests that the specificity of glycogen synthase and starch synthase and their concerted action with BE play an important role in determining the structure of the polysaccharide synthesized. PMID:7862674

Guan, H; Kuriki, T; Sivak, M; Preiss, J

1995-02-14

13

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

PubMed Central

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

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

2010-01-01

14

Cytosines Do It, Thymines Do It, Even Pseudouridines Do It--Base Flipping by an Enzyme that Acts on RNA  

PubMed Central

In the December 28, 2001 issue of Cell, Hoang and Ferré-D’Amaré report the structure of a tRNA pseudouridine synthase, showing the target uridine flipped out from the tRNA and confirming that base flipping is not limited to enzymes that act on DNA.

Cheng, Xiaodong; Blumenthal, Robert M.

2014-01-01

15

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 ...

16

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

PubMed Central

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

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

2014-01-01

17

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

PubMed

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

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

2014-01-01

18

Presynaptically acting snake venom phospholipase A 2 enzymes attack unique substrates  

Microsoft Academic Search

Synaptosomes were incubated with bovine serum albumin (BSA) to examine whether the presynaptic action of snake venom phospholipase A2 (PLA2) toxins is due either to the release of fatty acids resistant to extraction by BSA or to the liberation of a specific fatty acid type. In the presence of BSA (0.5% or 1.0%) two PLA2 enzymes from Naja naja atra

Jeffrey E. Fletcher; Ming-Shi Jiang

1995-01-01

19

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+.

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

2004-01-01

20

Compartmental and enzyme kinetic modeling to elucidate the biotransformation pathway of a centrally acting antitrypanosomal prodrug.  

PubMed

DB868 [2,5-bis [5-(N-methoxyamidino)-2-pyridyl] furan], a prodrug of the diamidine DB829 [2,5-bis(5-amidino-2-pyridyl) furan], has demonstrated efficacy in murine models of human African trypanosomiasis. A cross-species evaluation of prodrug bioconversion to the active drug is required to predict the disposition of prodrug, metabolites, and active drug in humans. The phase I biotransformation of DB868 was elucidated using liver microsomes and sandwich-cultured hepatocytes from humans and rats. All systems produced four NADPH-dependent metabolites via O-demethylation (M1, M2) and N-dehydroxylation (M3, M4). Compartmental kinetic modeling of the DB868 metabolic pathway suggested an unusual N-demethoxylation reaction that was supported experimentally. A unienzyme Michaelis-Menten model described the kinetics of M1 formation by human liver microsomes (HLMs) (K(m), 11 ?M; V(max), 340 pmol/min/mg), whereas a two-enzyme model described the kinetics of M1 formation by rat liver microsomes (RLMs) (K(m1), 0.5 ?M; V(max1), 12 pmol/min/mg; K(m2), 27 ?M; V(max2), 70 pmol/min/mg). Human recombinant CYP1A2, CYP3A4, and CYP4F2, rat recombinant Cyp1a2 and Cyp2d2, and rat purified Cyp4f1 catalyzed M1 formation. M2 formation by HLMs exhibited allosteric kinetics (S(50), 18 ?M; V(max), 180 pmol/mg), whereas M2 formation by RLMs was negligible. Recombinant CYP1A2/Cyp1a2 catalyzed M2 formation. DB829 was detected in trace amounts in HLMs at the end of the 180-min incubation and was detected readily in sandwich-cultured hepatocytes from both species throughout the 24-h incubation. These studies demonstrated that DB868 biotransformation to DB829 is conserved between humans and rats. An improved understanding of species differences in the kinetics of DB829 formation would facilitate preclinical development of a promising antitrypanosomal prodrug. PMID:23223498

Generaux, Claudia N; Ainslie, Garrett R; Bridges, Arlene S; Ismail, Mohamed A; Boykin, David W; Tidwell, Richard R; Thakker, Dhiren R; Paine, Mary F

2013-02-01

21

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

PubMed Central

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

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

2011-01-01

22

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

PubMed

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

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

2011-03-22

23

Mechanism of action of the endo-(1-->3)-alpha-glucanase MutAp from the mycoparasitic fungus Trichoderma harzianum.  

PubMed

(1-->3)-alpha-glucanases catalyze the hydrolysis of fungal cell wall (1-->3)-alpha-glucan, and function during cell division of yeasts containing this cell wall component or act in mycoparasitic processes. Here, we characterize the mechanism of action of the (1-->3)-alpha-glucanase MutAp from the mycoparasitic fungus Trichoderma harzianum. We observed that MutAp releases predominantly beta-glucose upon hydrolysis of crystalline (1-->3)-alpha-glucan, indicating inversion of the anomeric configuration. After having identified (1-->3)-alpha-glucan tetrasaccharide as the minimal substrate for MutAp, we showed that reduced (1-->3)-alpha-glucan pentasaccharide is cleaved into a trisaccharide and a reduced disaccharide, demonstrating that MutAp displays endo-hydrolytic activity. We propose a model for the catalytic mechanism of MutAp, whereby the enzyme breaks an intrachain glycosidic linkage of (1-->3)-alpha-glucan, and then continues its hydrolysis towards the non-reducing end by releasing beta-glucose residues in a processive manner. PMID:16780840

Grün, Christian H; Dekker, Nick; Nieuwland, Alexander A; Klis, Frans M; Kamerling, Johannis P; Vliegenthart, Johannes F G; Hochstenbach, Frans

2006-07-10

24

Bovine serum albumin does not completely block synaptosomal cholinergic activities of presynaptically acting snake venom phospholipase A 2 enzymes  

Microsoft Academic Search

Bovine serum albumin (BSA), which binds fatty acids, was used to test the contribution of free fatty acid to the presynaptic toxicity of phospholipase A2 (PLA2) enzymes. The effects of BSA on inhibition of [14C]choline uptake and stimulation of [14C]acetylcholine (ACh) release in synaptosomes by PLA2 enzymes that do not have a predominant presynaptic action at the neuromuscular junction (PS?)

Jeffrey E. Fletcher; Robert J. Storella; Ming-Shi Jiang

1995-01-01

25

Remote control of DNA-acting enzymes by varying the Brownian dynamics of a distant DNA end  

PubMed Central

Enzyme rates are usually considered to be dependent on local properties of the molecules involved in reactions. However, for large molecules, distant constraints might affect reaction rates by affecting dynamics leading to transition states. In single-molecule experiments we have found that enzymes that relax DNA torsional stress display rates that depend strongly on how the distant ends of the molecule are constrained; experiments with different-sized particles tethered to the end of 10-kb DNAs reveal enzyme rates inversely correlated with particle drag coefficients. This effect can be understood in terms of the coupling between molecule extension and local molecular stresses: The rate of bead thermal motion controls the rate at which transition states are visited in the middle of a long DNA. Importantly, we have also observed this effect for reactions on unsupercoiled DNA; other enzymes show rates unaffected by bead size. Our results reveal a unique mechanism through which enzyme rates can be controlled by constraints on macromolecular or supramolecular substrates.

Bai, Hua; Kath, James E.; Zorgiebel, Felix Manuel; Sun, Mingxuan; Ghosh, Pallavi; Hatfull, Graham F.; Grindley, Nigel D. F.; Marko, John F.

2012-01-01

26

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

27

Redox-enzymes, cells and micro-organisms acting on carbon nanostructures transformation: a mini-review.  

PubMed

Carbon nanotubes, graphene and fullerenes are actual nanomaterials with many applications in different industrial areas, with increasing potentialities in the field of nanomedicine. Recently, different proactive approaches on toxicology and safety management have become the focus of intense interest once the industrial production of these materials had a significant growth in the last years, even though their short- and long-term behaviors are not yet fully understood. The most important concerns involving these carbon-based nanomaterials are their stability and potential effects of their life cycles on animals, humans, and environment. In this context, this mini review discuss the biodegradability of these materials, particularly through redox-enzymes, micro-organisms and cells, to contribute toward the design of biocompatible and biodegradable functionalized carbon nanostructures, in order to use these materials safely and with minimum impact on the environment. PMID:23225699

Seabra, Amedea B; Paula, Amauri J; Durán, Nelson

2013-01-01

28

Amylolytic Enzymes  

Microsoft Academic Search

Amylolytic enzymes act on starch and related oligo- and polysaccharides. The recent wealth of information on the DNA sequence,\\u000a structural analysis and catalytic mechanism led to the extensive research on starch hydrolyzing enzymes which led the concept\\u000a of the alpha amylase family. Amylolytic enzymes are extensively used in starch liquefaction, paper industries, food, pharmaceutical\\u000a and sugar industries which demands a

Dhanya Gangadharan; Swetha Sivaramakrishnan

29

The EAL domain protein YciR acts as a trigger enzyme in a c-di-GMP signalling cascade in E. coli biofilm control.  

PubMed

C-di-GMP-which is produced by diguanylate cyclases (DGC) and degraded by specific phosphodiesterases (PDEs)-is a ubiquitous second messenger in bacterial biofilm formation. In Escherichia coli, several DGCs (YegE, YdaM) and PDEs (YhjH, YciR) and the MerR-like transcription factor MlrA regulate the transcription of csgD, which encodes a biofilm regulator essential for producing amyloid curli fibres of the biofilm matrix. Here, we demonstrate that this system operates as a signalling cascade, in which c-di-GMP controlled by the DGC/PDE pair YegE/YhjH (module I) regulates the activity of the YdaM/YciR pair (module II). Via multiple direct interactions, the two module II proteins form a signalling complex with MlrA. YciR acts as a connector between modules I and II and functions as a trigger enzyme: its direct inhibition of the DGC YdaM is relieved when it binds and degrades c-di-GMP generated by module I. As a consequence, YdaM then generates c-di-GMP and-by direct and specific interaction-activates MlrA to stimulate csgD transcription. Trigger enzymes may represent a general principle in local c-di-GMP signalling. PMID:23708798

Lindenberg, Sandra; Klauck, Gisela; Pesavento, Christina; Klauck, Eberhard; Hengge, Regine

2013-07-17

30

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

31

ENZYME: Enzyme Nomenclature Database  

NSDL National Science Digital Library

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

32

Cis-Acting Elements in the 5?-Flanking DNA of the Malic Enzyme Gene Regulate Tissue-Specific T3Responsiveness in Chick Embryo Fibroblasts  

Microsoft Academic Search

Triiodothyronine (T3) stimulates transcription of the malic enzyme gene in chick embryo hepatocytes (CEH), but not in chick embryo fibroblasts (CEF), even though the two cell types contain similar nuclear T3 binding activities (F. B. Hillgartner, W. Chen, and A. G. Goodridge,J. Biol. Chem.267, 12299–12306, 1992). Based on Western blot analyses and gel electrophoretic mobility-shift assays, differences in mass of

Sung Soo Chung; Alan G Goodridge

1999-01-01

33

Mutants of Escherichia coli Heat-Labile Toxin Act as Effective Mucosal Adjuvants for Nasal Delivery of an Acellular Pertussis Vaccine: Differential Effects of the Nontoxic AB Complex and Enzyme Activity on Th1 and Th2 Cells  

PubMed Central

Mucosal delivery of vaccines is dependent on the identification of safe and effective adjuvants that can enhance the immunogenicity of protein antigens administered by nasal or oral routes. In this study we demonstrate that two mutants of Escherichia coli heat-labile toxin (LT), LTK63, which lacks ADP-ribosylating activity, and LTR72, which has partial enzyme activity, act as potent mucosal adjuvants for the nasal delivery of an acellular pertussis (Pa) vaccine. Both LTK63 and LTR72 enhanced antigen-specific serum immunoglobulin G (IgG), secretory IgA, and local and systemic T-cell responses. Furthermore, using the murine respiratory challenge model for infection with Bordetella pertussis, we demonstrated that a nasally delivered diphtheria, tetanus, and acellular pertussis (DTPa) combination vaccine formulated with LTK63 as an adjuvant conferred a high level of protection, equivalent to that generated with a parenterally delivered DTPa vaccine formulated with alum. This study also provides significant new information on the roles of the binding and enzyme components of LT in the modulation of Th1 and Th2 responses. LTK63, which lacks enzyme activity, promoted T-cell responses with a mixed Th1–Th2 profile, but LTR72, which retains partial enzyme activity, and the wild-type toxin, especially at low dose, induced a more polarized Th2-type response and very high IgA and IgG antibody titers. Our findings suggest that the nontoxic AB complex has broad adjuvant activity for T-cell responses and that the ADP-ribosyltransferase activity of the A subunit also appears to modulate cytokine production, but its effect on T-cell subtypes, as well as enhancing, may be selectively suppressive.

Ryan, Elizabeth J.; McNeela, Edel; Murphy, Geraldine A.; Stewart, Helen; O'hagan, Derek; Pizza, Mariagrazia; Rappuoli, Rino; Mills, Kingston H. G.

1999-01-01

34

Catalyzed enzyme electrodes  

SciTech Connect

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

1993-07-13

35

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

36

ACT Test  

MedlinePLUS

... a satellite laboratory. ^ Back to top 2. Can lupus anticoagulant interfere with the ACT test? The ACT test is generally not affected by lupus anticoagulant (LAC). Nevertheless, the presence of LAC has ...

37

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

38

Juggling Act  

ERIC Educational Resources Information Center

Two education bills from George W. Bush's first term are long overdue for reauthorization. One, of course, is the No Child Left Behind Act (NCLB), passed in late 2001. The other is the Education Sciences Reform Act (ESRA), which in November 2002 replaced the Office of Educational Research and Improvement (OERI) with a new Institute of Education…

Rudalevige, Andrew

2009-01-01

39

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

40

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

41

The NAD(P)H-Utilizing Glutamate Dehydrogenase of Bacteroides thetaiotaomicronBelongs to Enzyme Family I, and Its Activity Is Affected bytrans-Acting Gene(s) Positioned Downstream ofgdhA  

Microsoft Academic Search

Previous studies have suggested that regulation of the enzymes of ammonia assimilation in human colonic Bacteroides species is coordinated differently than in other eubacteria. The gene encoding an NAD(P)H- dependent glutamate dehydrogenase (gdhA )i nBacteroides thetaiotaomicron was cloned and expressed in Escherichia coli by mutant complementation from the recombinant plasmid pANS100. Examination of the predicted GdhA amino acid sequence revealed

LAURIE BAGGIO; ANDMARK MORRISON

42

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

43

Engineering enzymes  

PubMed Central

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

Moser, Christopher C.

2014-01-01

44

Zinc Enzymes.  

ERIC Educational Resources Information Center

Discusses the role of zinc in various enzymes concerned with hydration, hydrolysis, and redox reactions. The binding of zinc to protein residues, properties of noncatalytic zinc(II) and catalytic zinc, and the reactions catalyzed by zinc are among the topics considered. (JN)

Bertini, I.; And Others

1985-01-01

45

New enzymes active towards pectic structures  

Microsoft Academic Search

Microbial pectinases have been used for fruit and vegetable processing for already more than half a decade. With respect to application as well as to fundamental research, most attention has been paid to those enzymes acting towards the ‘smooth’ homogalacturonan part of the pectin molecule (i.e. polygalacturonase, pectin lyase, pectate lyase, pectin methyl esterase). More recently, enzymes active towards the

G. Beldman; M. Mutter; M. J. F. Searle-van Leeuwen; L. A. M. van den Broek; H. A. Schols; A. G. J. Voragen

1996-01-01

46

Act resilient.  

PubMed

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

Joseph, Genie; Bice-Stephens, Wynona

2014-01-01

47

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

48

Enzyme extraction, functional properties and application of leaf protein fractions of nettle  

Microsoft Academic Search

Use of alkaline protease (subtilisin) gave nearly full extraction of nettle leaf protein (over 90%). The difference of molecular seaving profiles of enzyme and without enzyme extracted protein fractions is not so remarcable. That signifys that enzyme extraction doesn't concern protein by it self but cell membrane. The added enzyme acts by weakening the cell membrane. The enzyme extracted fractions

Pencho Dalev; Anna Ljubomirova; Ivailo Ivanov

1996-01-01

49

Acting Presidents Should Act like Presidents.  

ERIC Educational Resources Information Center

Governing boards are advised to give an "acting" president full authority and responsibility. Conclusions include the following: (1) leadership must be exercised, (2) noncandidates should be appointed, (3) institutional staff must support the acting staff, (4) acting staff must be active and communicative with constituents, and (5) transitional…

De Zonia, Robert H.

1979-01-01

50

Enzyme Immobilization Alternatives for the Enzyme Alarm.  

National Technical Information Service (NTIS)

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

H. W. Levin E. S. Erenrich

1976-01-01

51

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

52

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.

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

2012-01-01

53

Development of Immobilized Enzyme Systems for Enhancement of Biological Waste Treatment Processes.  

National Technical Information Service (NTIS)

Degradation and utilization of waste water nutrients by microbial action is controlled by a complex enzyme system. In attempts to produce a faster-acting system, a method was developed to biochemically fractionate the microbial enzymes from activated slud...

L. Slote

1970-01-01

54

Biocatalytic Single Enzyme Nanoparticles  

SciTech Connect

As an innovative way of enzyme stabilization, we recently developed a new enzyme composite of nano-meter scale that we call "single-enzyme nanoparticles (SENs)" (9). Each enzyme molecule is surrounded with a porous composite organic/inorganic network of less than a few nanometers think. This approach represents a new type of enzyme-containing nanostructure. In experiments with perotease (chymotrypsin, CT), the activity of single enzyme nanoparticle form of the enzyme was greatly stabilized compared to the free form, without imposing a serious mass transfer limitation of substrates. In this chapter we will describe the synthesis, characterization and catalytic activity of the new SENs.

Grate, Jay W.; Kim, Jungbae

2004-03-31

55

ACTS propagation program  

NASA Astrophysics Data System (ADS)

The Advanced Communications Technology Satellite (ACTS) Propagation Program is organized to fulfill certain needs and requirements of the ACTS community. It is hoped that issues related to propagation effects in the context of ACTS experiments can be addressed and resolved by this program. The objectives of the ACTS Propagation Program are included in but not limited to planning for propagation measurements and studies using ACTS; organizing propagation experimenters who want to use ACTS into one group; developing observation stations for ACTS propagation measurements; supervising data collection, analysis, and ensure uniformity of data recording among various experimenters; and assisting the ACTS Program Office to carry out its objectives. This program is organized and managed by the NASA Propagation Program at the Jet Propulsion Laboratory. Financial support for this program is provided by NASA.

Davarian, Faramaz

1990-07-01

56

ACTS data center  

NASA Technical Reports Server (NTRS)

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

Syed, Ali; Vogel, Wolfhard J.

1993-01-01

57

Recovery Act Milestones  

ScienceCinema

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

Rogers, Matt

2013-05-29

58

Recovery Act Milestones  

SciTech Connect

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

Rogers, Matt

2009-01-01

59

Enzyme Immobilization Alternatives for the Enzyme Alarm.  

National Technical Information Service (NTIS)

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

H. W. Levin E. S. Erenrich

1975-01-01

60

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

61

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

62

Inhibition Enzyme Sensor for Nicotine, Nicotinamide and Nicotinic Acid Determination  

NASA Astrophysics Data System (ADS)

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

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

2000-12-01

63

DNA Gyrase: An Enzyme that Introduces Superhelical Turns into DNA  

Microsoft Academic Search

Relaxed closed-circular DNA is converted to negatively supercoiled DNA by DNA gyrase. This enzyme has been purified from Escherichia coli cells. The reaction requires ATP and Mg++ and is stimulated by spermidine. The enzyme acts equally well on relaxed closed-circular colicin E1, phage lambda , and simian virus 40 DNA. The final superhelix density of the DNA can be considerably

Martin Gellert; Kiyoshi Mizuuchi; Mary H. O'Dea; Howard A. Nash

1976-01-01

64

Mutagenicity of anticancer drugs that inhibit topoisomerase enzymes  

Microsoft Academic Search

Topoisomerases are enzymes that catalyse the transient breakage and rejoining of either one (topo I) or two (topo II) DNA strands, to allow one strand to pass through another and prevent unresolvable tangles during processes such as DNA replication. A number of important clinical antitumour agents act through inhibition of topo II enzymes, while some topo I inhibitors appear likely

Lynnette R. Ferguson; Bruce C. Baguley

1996-01-01

65

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.

2012-01-01

66

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

67

Aminoglycoside-modifying enzymes.  

PubMed

Bacterial resistance to the aminoglycoside antibiotics is most frequently associated with the expression of modifying enzymes that can phosphorylate, adenylate or acetylate these compounds. The recent availability of representative crystal structures for all three classes of modifying enzymes has greatly expanded our knowledge of enzyme function, and has revealed unexpected and exciting connections to other families of enzymes. Furthermore, the complete genome sequences for several bacteria have revealed many potential aminoglycoside-resistance elements. PMID:10508725

Wright, G D

1999-10-01

68

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

69

Self-powered enzyme micropumps.  

PubMed

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

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

2014-05-01

70

Self-powered enzyme micropumps  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

71

ACTS Experiments Program  

NASA Technical Reports Server (NTRS)

An overview of the ACTS Experiments Program is presented. ACTS is being developed and will flight test the advanced technologies associated with: a Ka-band multibeam antenna, onboard signal processing and switching as well as laser communications. A nominal 3 yr experiments program is planned. Through the experiments program, the capabilities of the ACTS system will be made available to U.S. industry, university and government experimenters to test, prove the feasibility and evaluate the key ACTS system technologies. Communication modes of operation using the baseband processor and microwave switch matrix are presented, along with the antenna coverage pattern. Potential experiment categories are also presented and briefly discussed. An overall schedule of activities associated with the experiments program is outlined. Results of the ACTS Experiments Program will provide information vital to successful industry implementation of ACTS technology in a future operational system.

Schertler, R. J.

1986-01-01

72

Enzyme Loading of Erythrocytes  

PubMed Central

We demonstrated that ?-glucosidase and ?-galactosidase can be trapped inside erythrocytes by rapid hemolysis of the cell in the presence of these enzymes. Enzyme enters only during hemolysis, and optimum uptake occurs within 60 sec. There is no loss in cell number after hemolysis-induced enzyme uptake, and the ghosts have only a slightly increased mean cell volume. Smaller proteins enter more readily than larger proteins, although enzymes with a molecular weight of at least 180,000 can be readily entrapped by erythrocytes. This finding may provide a useful approach to the problem of enzyme replacement in certain diseases, including Gaucher's disease.

Ihler, Garret M.; Glew, Robert H.; Schnure, Frederick W.

1973-01-01

73

Enzymes of Ethylene Biosynthesis  

PubMed Central

The properties of enzymes involved in ethylene biosynthesis are reviewed and progress toward the purification of these enzymes is described. The enzyme whose activity usually limits ethylene biosynthesis is 1-aminocyclopropane-1-carboxylate (ACC) synthase. Even though its level in plants is extremely low, it has now been purified from several sources. The enzyme that converts ACC to ethylene does not survive homogenization, apparently because it is membrane-bound and because its activity requires membrane integrity. Properties of this enzyme have been elucidated in vivo and in vacuolar preparations which possess the capacity to convert ACC to ethylene.

Kende, Hans

1989-01-01

74

ACTS propagation terminal update  

NASA Astrophysics Data System (ADS)

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

1992-08-01

75

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.

2014-01-01

76

The Community Corrections Act  

Microsoft Academic Search

Minnesota's Community Corrections Act, which became law in 1973, is examined in detail. Its development, fundamental precepts, and initial re sults are included. The act combined existing fragmented policies into a comprehensive strategy and defined the relationship between the state and local levels of government. It is based upon the assumptions that incarceration will continue to be needed for serious

Kenneth F. Schoen

1978-01-01

77

Recovery Act Funding Awards  

Cancer.gov

NCI has quickly moved to utilize Recovery Act funds for projects. Deserving projects are being funded through new grants and contracts as well as supplements to existing grants. Information on this page will be periodically updated so please check back to see how NCI is spending Recovery Act funds.

78

Bioterrorism Act of 2002  

MedlinePLUS

... the United States. Congress responded by passing the Public Health Security and Bioterrorism Preparedness and Response Act of 2002 (the Bioterrorism Act), which President Bush signed into law June 12, ... and Other Public Health Emergencies Title II -- Enhancing Controls on Dangerous ...

79

Americans with Disabilities Act.  

ERIC Educational Resources Information Center

Addressed to school board members, this article attempts to summarize requirements of the Americans with Disabilities Act (ADA) and its implications for school districts. It warns against hasty purchase of private compliance assistance; then provides an overview of each of the Act's five Titles which address employment practices, activities…

Updating School Board Policies, 1992

1992-01-01

80

Rational enzyme redesign  

SciTech Connect

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

Ornstein, R.L.

1994-05-01

81

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

82

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

83

Nanostructures for enzyme stabilization  

SciTech Connect

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

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

2006-02-02

84

Enzymes from extremophiles.  

PubMed

The industrial application of enzymes that can withstand harsh conditions has greatly increased over the past decade. This is mainly a result of the discovery of novel enzymes from extremophilic microorganisms. Recent advances in the study of extremozymes point to the acceleration of this trend. In particular, enzymes from thermophilic organisms have found the most practical commercial use to date because of their overall inherent stability. This has also led to a greater understanding of stability factors involved in adaptation of these enzymes to their unusual environments. PMID:11282340

Demirjian, D C; Morís-Varas, F; Cassidy, C S

2001-04-01

85

Microbial amylolytic enzymes.  

PubMed

Starch-degrading, amylolytic enzymes are widely distributed among microbes. Several activities are required to hydrolyze starch to its glucose units. These enzymes include alpha-amylase, beta-amylase, glucoamylase, alpha-glucosidase, pullulan-degrading enzymes, exoacting enzymes yielding alpha-type endproducts, and cyclodextrin glycosyltransferase. Properties of these enzymes vary and are somewhat linked to the environmental circumstances of the producing organisms. Features of the enzymes, their action patterns, physicochemical properties, occurrence, genetics, and results obtained from cloning of the genes are described. Among all the amylolytic enzymes, the genetics of alpha-amylase in Bacillus subtilis are best known. Alpha-Amylase production in B. subtilis is regulated by several genetic elements, many of which have synergistic effects. Genes encoding enzymes from all the amylolytic enzyme groups dealt with here have been cloned, and the sequences have been found to contain some highly conserved regions thought to be essential for their action and/or structure. Glucoamylase appears usually in several forms, which seem to be the results of a variety of mechanisms, including heterogeneous glycosylation, limited proteolysis, multiple modes of mRNA splicing, and the presence of several structural genes. PMID:2548811

Vihinen, M; Mäntsälä, P

1989-01-01

86

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

87

Enzyme Immobilization Alternatives For the Enzyme Alarm.  

National Technical Information Service (NTIS)

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

H. W. Levin E. S. Erenrich

1975-01-01

88

Cotton cellulose: enzyme adsorption and enzymic hydrolysis  

Microsoft Academic Search

The adsorption of a crude cellulase complex from Trichoderma viride on variously pretreated cotton cellulose samples was studied in the framework of the Langmuir approach at 2-8 degrees. The saturation amount of adsorbed enzyme was related to the susceptibility of the substrates to hydrolysis. In every case the adsorption process was faster by 2-3 orders of magnitude than the hydrolysis

P. L. Beltrame; P. Carniti; B. Focher; A. Marzetti; M. Cattaneo

1982-01-01

89

Federal Tort Claims Act.  

National Technical Information Service (NTIS)

This casebook is a compilation of cases and materials on the Federal Tort Claims Act designed to provide source material for students at The Judge Advocate General's School. These materials are not official Department of the Army policy. The organization ...

1999-01-01

90

Public Health Service Act  

Cancer.gov

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

91

ACTS Multibeam Antenna.  

National Technical Information Service (NTIS)

The Advanced Communications Technology Satellite (ACTS) to be launched in 1993 introduces several new technologies including a multibeam antenna (MBA) operating at Ka-band. The satellite is introduced briefly, and then the MBA, consisting of electrically ...

F. A. Regier

1992-01-01

92

Enzyme immobilization on tritylagarose  

Microsoft Academic Search

A method is described for the immobilization on tritylated agarose or Sepharose columns of a wide spectrum of enzymes, including types useful in contemporary biochemistry\\/molecular biology, many of which have never before been reported as immobilized. The method involves the formation of noncovalent hydrophobic bonds between the enzymes and trityl groups which are attached to the agarose by means of

Peter Cashion; Ali Javed; Dolores Harrison; Jane Seeley; Victor Lentini; Ganesh Sathe

1982-01-01

93

Enzymes from psychrophilic organisms  

Microsoft Academic Search

Psychrophilic organisms such as micro-organisms and other ectothermic species living in polar, deep- sea or any constantly low temperature environments, produce enzymes adapted to function at low temperature. These enzymes are characterized by a high catalytic efficiency at low and moderate temperatures but are rather thermolabile. Due to their high specific activity and their rapid inactivation at temperatures as low

Georges Feller; Emmanuel Narinx; Jean Louis Arpigny; Mohamed Aittaleb; Etienne Baise; Sabine Genicot; Charles Gerday

1996-01-01

94

Aromatase: a neuroprotective enzyme  

Microsoft Academic Search

Estradiol, in addition to its participation in neuroendocrine regulation and sexual behavior, has neuroprotective properties. Different types of brain injury induce the expression of the enzyme aromatase in reactive astroglia. This enzyme catalyzes the conversion of testosterone and other C19 steroids to estradiol. Genetic or pharmacological inhibition of brain aromatase results in marked neurodegeneration after different forms of mild neurodegenerative

Luis M. Garcia-Segura; Sergio Veiga; Amanda Sierra; Roberto C. Melcangi; Iñigo Azcoitia

2003-01-01

95

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

96

Enzymes and Reactor Engineering.  

National Technical Information Service (NTIS)

In the first part of this report, a brief review of the state of the art in the field of immobilized enzymes is presented. Topics covered include: (1) silanization of porous glass; (2) covalent bonding reaction schemes; and (3) some enzymes of current int...

H. O. Hultin J. R. Kittrell R. L. Laurence

1972-01-01

97

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.

98

ACTS broadband aeronautical terminal  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

99

Enzyme nanoband electrodes  

SciTech Connect

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

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

1993-07-01

100

Immobilized enzymes in analytical chemistry  

Microsoft Academic Search

The use of immobilized enzymes in analysis has increased tremendously in recent years. The various applications can be categorized by the manner in which the enzyme is used as: transducer bound enzymes; immobilized enzyme reactors; and miscellaneous batch and membrane applications. Enzyme electrodes, making use of either potentiometric or amperometric detection, are the best known example of the first class.

Larry D. Bowers; Peter W. Carr

101

Freedom of Information Act  

NSDL National Science Digital Library

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

102

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

103

Synthetic Helizyme Enzymes.  

National Technical Information Service (NTIS)

The object of this project is to design and synthesize totally new, totally synthetic small molecules having specific enzyme activity. The ultimate goal is to design and synthesize a molecule with cholinesterase activity. The initial goal is to design and...

J. M. Stewart K. Hahn

1987-01-01

104

Immobilized Enzymes in Biocathodes.  

National Technical Information Service (NTIS)

Disclosed is an improved biofuel cell having a cathode comprising a dual function membrane, which contains an oxygen oxidoreductase enzyme immobilized within a buffered compartment of the membrane and an electron transport mediator which transfers electro...

B. Treu S. Topcagic S. D. Minteer

2004-01-01

105

Affordable Care Act.  

PubMed

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

Rak, Sofija; Coffin, Janis

2013-01-01

106

STUDIES ON ENZYME ACTION  

PubMed Central

The hydrolyzing actions of various preparations of the adult eel were studied on ten esters in the usual way. The results are presented in the form of curves for the relative actions and in a table for the absolute actions obtained in one complete experiment. The separation of the enzyme material in some cases into an active portion and a co-enzyme, the mixture showing greater actions on some esters than the sums of the individual actions, is described and discussed.

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

1926-01-01

107

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.

108

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

109

Assertive Community Treatment (ACT)  

MedlinePLUS

... org 3803 N. Fairfax Drive, Suite 100, Arlington, Va. 22203 1 What is assertive community treatment? Assertive community treatment ( ... SHEET NAMI • The National Alliance on Mental Illness • 1 (800) 950-NAMI • www.nami.org 3803 N. Fairfax Drive, Suite 100, Arlington, Va. 22203 2 ACT has a unique focus on ...

110

Older Americans Act  

MedlinePLUS

... organizations representing 400 Tribes. The OAA also includes community service employment for low-income older Americans; training, research, ... Part 1321 (Title III) Grants for State and Community Programs on ... and Nutrition Services Older Americans Act Regulations (1988), 45 CFR Part ...

111

Good Samaritan acts.  

PubMed

Good Samaritan Acts are those in which aid is rendered to a needy victim of injury or sudden illness. No antecedent relationship exists with the good samaritan, and no remuneration is anticipated. Emergency physicians have an ethical obligation beyond that of other citizens to provide aid in such situations of medical need; professional and legal standards support that obligation. PMID:10429643

Daniels, S

1999-05-01

112

Fast-Acting Valve.  

National Technical Information Service (NTIS)

A fast-acting valve includes an annular valve seat that defines an annular valve orifice between the edges of the annular valve seat, an annular valve plug sized to cover the valve orifice when the valve is closed, and a valve-plug holder for moving the a...

B. V. Wojciechowski R. J. Pegg

2003-01-01

113

Adults' Interpretation of Infants' Acts.  

ERIC Educational Resources Information Center

The selection of acts from the stream of infant behavior is examined. Adults (140 mothers, fathers, and other men and women) viewed videotapes of 9-, 15-, and 21-month-old infants. One half noted meaningful acts; the other half noted intentionally communicative acts. Parents selected more meaningful acts than nonparents and agreed more about…

Adamson, Lauren B.; And Others

1987-01-01

114

Enzyme immobilization on tritylagarose  

SciTech Connect

A method is described for the immobilization on tritylated agarose or Sepharose columns of a wide spectrum of enzymes, including types useful in contemporary biochemistry/molecular biology, many of which have never before been reported as immobilized. The method involves the formation of noncovalent hydrophobic bonds between the enzymes and trityl groups which are attached to the agarose by means of ether bonds. The immobilization of calf intestinal and E. coli alkaline phosphatases to tritylagarose is reported in detail. Their binding strength, binding capacity, and long-term stability (greater than six months) are described as a function of the salt concentration, pH, buffer type, and degree of agarose substitution. Homologies are noted between tritylagarose-bound and membrane-bound phosphatases. This method compares favorably with other methods, covalent or otherwise, reported to date, in terms of the enzyme immobilization yield (ca. 100%), the mildness of conditions, resulting, in most cases, in the retention of a high degree of activity, the ease and speed of the manipulations, and the long-term stability of the immobilized enzyme. Further, it is noted that highly tritylated and crosslinked Sephadex G10 selectively and mildly removes detergents from enzyme solutions. (Refs. 64).

Cashion, P.; Javed, A.; Harrison, D.; Seeley, J.; Lentini, V.; Sathe, G.

1982-02-01

115

Aminoglycoside Modifying Enzymes  

PubMed Central

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

Ramirez, Maria S.; Tolmasky, Marcelo E.

2010-01-01

116

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.

117

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

118

Freedom of Information Act  

USGS Publications Warehouse

The Freedom of Information Act( FOIA), 5 U.S.C.§ 552, as amended, generally provides that any person has a right to request access to Federal agency records. The USGS proactively promotes information disclosure as inherent to its mission of providing objective science to inform decisionmakers and the general public. USGS scientists disseminate up-to-date and historical scientific data that are critical to addressing national and global priorities.

Newman, D.J.

2012-01-01

119

Toxic Substances Control Act  

SciTech Connect

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

Not Available

1992-05-15

120

The ACTS multibeam antenna  

NASA Technical Reports Server (NTRS)

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

Regier, Frank A.

1992-01-01

121

Hfq stimulates the activity of the CCA-adding enzyme  

PubMed Central

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

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

2007-01-01

122

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

123

Cellulase a Key Enzyme in Fermentation: Annual Report, 1985--1986.  

National Technical Information Service (NTIS)

Many microbial cellulase systems are comprised of multiple components namely, endoglucanase (EG), cellobiohydrolase (CBH), and betaglucosidabe. These three types of enzyme of the cellulase complex act synergistically but their mechanism of interaction in ...

D. E. Eveleigh J. D. Macmillan

1986-01-01

124

Localization of the ActIII actinorhodin polyketide ketoreductase to the cell wall  

Microsoft Academic Search

Structurally diverse polyketides provide a rich reservoir of bioactive molecules. Actinorhodin, a model aromatic polyketide, is synthesized by minimal type II polyketide synthase and tailoring enzymes. The ActIII actinorhodin ketoreductase is a key tailoring enzyme in actinorhodin biosynthesis. With purified antibodies against actinorhodin polyketide synthase a subunit (KSa) and ketoreductase, we conducted systematic localization experiments of the two proteins in

Xin-Ping Xu; Zhi-Jun Wang; Ke-Qiang Fan; Sheng-Lan Wang; Cui-Juan Jia; Hui Han; Eswar Ramalingam; Ke-Qian Yang

2008-01-01

125

Immobilized Enzymes: Methods and Applications  

Microsoft Academic Search

Immobilized enzymes are used in organic syntheses to fully exploit the technical and economical advantages of biocatalysts\\u000a based on isolated enzymes. Immobilization enables the separation of the enzyme catalyst easily from the reaction mixture,\\u000a and can lower the costs of enzymes dramatically. This is true for immobilized enzyme preparations that provide a well-balanced\\u000a overall performance, based on reasonable immobilization yields,

Wilhelm Tischer; Frank Wedekind

126

Blockade of Endocannabinoid-Degrading Enzymes Attenuates Neuropathic Pain  

Microsoft Academic Search

Direct-acting cannabinoid receptor agonists are well known to reduce hyperalgesic responses and allodynia after nerve injury, although their psychoactive side effects have damped enthu- siasm for their therapeutic development. Alternatively, inhibiting fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL), the principal enzymes responsible for the degradation of the respective endogenous cannabinoids, anandamide (AEA) and 2-arachydonylglycerol (2-AG), reduce nociception in

S. G. Kinsey; J. Z. Long; S. T. O'Neal; R. A. Abdullah; J. L. Poklis; D. L. Boger; B. F. Cravatt; A. H. Lichtman

2009-01-01

127

An Oxidative Enzyme Boosting the Enzymatic Conversion of Recalcitrant Polysaccharides  

Microsoft Academic Search

Efficient enzymatic conversion of crystalline polysaccharides is crucial for an economically and environmentally sustainable bioeconomy but remains unfavorably inefficient. We describe an enzyme that acts on the surface of crystalline chitin, where it introduces chain breaks and generates oxidized chain ends, thus promoting further degradation by chitinases. This enzymatic activity was discovered and further characterized by using mass spectrometry and

Gustav Vaaje-Kolstad; Bjørge Westereng; Svein J. Horn; Zhanliang Liu; Hong Zhai; Morten Sørlie; Vincent G. H. Eijsink

2010-01-01

128

Implantable enzyme amperometric biosensors.  

PubMed

The implantable enzyme amperometric biosensor continues as the dominant in vivo format for the detection, monitoring and reporting of biochemical analytes related to a wide range of pathologies. Widely used in animal studies, there is increasing emphasis on their use in diabetes care and management, the management of trauma-associated hemorrhage and in critical care monitoring by intensivists in the ICU. These frontier opportunities demand continuous indwelling performance for up to several years, well in excess of the currently approved seven days. This review outlines the many challenges to successful deployment of chronically implantable amperometric enzyme biosensors and emphasizes the emerging technological approaches in their continued development. The foreign body response plays a prominent role in implantable biotransducer failure. Topics considering the approaches to mitigate the inflammatory response, use of biomimetic chemistries, nanostructured topographies, drug eluting constructs, and tissue-to-device interface modulus matching are reviewed. Similarly, factors that influence biotransducer performance such as enzyme stability, substrate interference, mediator selection and calibration are reviewed. For the biosensor system, the opportunities and challenges of integration, guided by footprint requirements, the limitations of mixed signal electronics, and power requirements, has produced three systems approaches. The potential is great. However, integration along the multiple length scales needed to address fundamental issues and integration across the diverse disciplines needed to achieve success of these highly integrated systems, continues to be a challenge in the development and deployment of implantable amperometric enzyme biosensor systems. PMID:22516142

Kotanen, Christian N; Moussy, Francis Gabriel; Carrara, Sandro; Guiseppi-Elie, Anthony

2012-05-15

129

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

130

Home Mortgage Disclosure Act  

NSDL National Science Digital Library

Enacted by Congress in 1975, the Home Mortgage Disclosure Act (HMDA) requires US banks, savings associations, credit unions, and other mortgage lending institutions to disclose their home mortgage and home improvement lending activity annually. Access to HMDA data with loan amounts by metropolitan area as well as the demographic make-up of applicants, is available at this Federal Financial Institutions Examination Council (FFIEC) page. Users can also search a database of FFIEC data depository locations with HMDA reports or obtain background information on HMDA history and the financial institutions it affects.

131

75 FR 29 - Privacy Act, Government in the Sunshine Act, Freedom of Information Act (“FOIA”), and Federal...  

Federal Register 2010, 2011, 2012, 2013

...Act, Government in the Sunshine Act, Freedom of Information Act (``FOIA...94-409, 90 Stat. 1241 (1976), the Freedom of Information Act of 1966, as amended...word ``meeting.'' Corrections to Freedom of Information Act Rules in Part 4...

2010-01-04

132

Aryl Thioglycoside-Based Affinity Purification of Exo-Acting Cellulases  

Microsoft Academic Search

The influence of ligand-coupling chemistry and mobile-phase composition on the interaction of exo-acting cellulases with an immobilized complementary ligand was investigated.p-Aminophenyl 1-thio-?-d-cellobioside (APTC) was used as a representative affinity ligand to which exo-acting cellulases (cellobiohydrolases, CBHs) preferentially bind. A “crude” cellulase preparation from the fungusTrichoderma reeseiserved as an enzyme source. The adsorption properties of the two principal exo-acting CBHs in

Kuakoon Piyachomkwan; Michael H. Penner

1998-01-01

133

Affordable Care Act and Women  

MedlinePLUS

... Myspace Close Text Size: A A A The Affordable Care Act and Women The Affordable Care Act is making health insurance coverage more affordable and ... coverage that meets their unique health needs. The Affordable Care Act invests in prevention and wellness , and gives women ...

134

Halophilic adaptation of enzymes.  

PubMed

It is now clear that the understanding of halophilic adaptation at a molecular level requires a strategy of complementary experiments, combining molecular biology, biochemistry, and cellular approaches with physical chemistry and thermodynamics. In this review, after a discussion of the definition and composition of halophilic enzymes, the effects of salt on their activity, solubility, and stability are reviewed. We then describe how thermodynamic observations, such as parameters pertaining to solvent-protein interactions or enzyme-unfolding kinetics, depend strongly on solvent composition and reveal the important role played by water and ion binding to halophilic proteins. The three high-resolution crystal structures now available for halophilic proteins are analyzed in terms of haloadaptation, and finally cellular response to salt stress is discussed briefly. PMID:10805563

Madern, D; Ebel, C; Zaccai, G

2000-04-01

135

Enzymes in amniotic fluid.  

PubMed

The determination of enzyme levels in cell-free amniotic fluid has proven useful in assessing fetal maturity and fetal well being, and is being utilized for the prenatal diagnosis of genetic disorders. The activities of amylase, alpha-galactosidase, phosphatidic acid phosphohydrolase, lysozyme and heat-stable alkaline phosphatase in amniotic fluid increase with gestational age and have an established relationship to fetal maturity. The ratio of amniotic fluid diamine oxidase activity to maternal serum activity (amniotic DAO/serum DAO) may be used as an indicator of the degree of rhesus isoimmunization after 28 weeks gestation. Creatine phosphokinase in amniotic fluid is elevated in cases of in utero fetal death and is of diagnostic significance. The prenatal diagnosis of Tay-Sachs disease, Sandhoff's disease, fucosidosis, GM1-gangliosidosis and I-cell disease have been made from the analysis of appropriate enzymes in cell-free amniotic fluid. PMID:193424

Watkins, B F; Bermes, E W

1977-01-01

136

Halophilic adaptation of enzymes  

Microsoft Academic Search

It is now clear that the understanding of halophilic adaptation at a molecular level requires a strategy of complementary\\u000a experiments, combining molecular biology, biochemistry, and cellular approaches with physical chemistry and thermodynamics.\\u000a In this review, after a discussion of the definition and composition of halophilic enzymes, the effects of salt on their activity,\\u000a solubility, and stability are reviewed. We then

D. Madern; C. Ebel; G. Zaccai

2000-01-01

137

Deubiquitylating enzymes and disease  

Microsoft Academic Search

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

Shweta Singhal; Matthew C Taylor; Rohan T Baker

2008-01-01

138

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

Microsoft Academic Search

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

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

2004-01-01

139

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

PubMed

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

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

2009-08-01

140

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

141

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

142

Triple acting radial seal  

SciTech Connect

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

143

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

144

Silica-Immobilized Enzyme Reactors.  

National Technical Information Service (NTIS)

Recent studies have demonstrated the applicability and versatility of immobilized enzyme reactors (IMERS) for chemical and biochemical synthesis and analysis. The majority of IMER systems rely on enzymes immobilized to packed matrices within flow-through ...

H. R. Luckarift

2007-01-01

145

Thermophilic cytochrome P450 enzymes.  

PubMed

Thermophilic cytochrome P450 enzymes are of potential interest from structural, mechanistic, and biotechnological points of view. The structures and properties of two such enzymes, CYP119 and CYP175A1, have been investigated and provide the foundation for future work on thermophilic P450 enzymes. PMID:16139791

Nishida, Clinton R; Ortiz de Montellano, Paul R

2005-12-01

146

Immobilized enzymes: crystals or carriers?  

Microsoft Academic Search

The advantages of immobilized over soluble enzymes arise from their enhanced stability and ease of separation from the reaction media, leading to significant savings in enzyme consumption. Immobilization methods range from binding to prefabricated carrier materials to packaging in enzyme crystals or powders. During their use, mass-transfer effects can produce substrate or pH gradients, which reduce the reaction rates and

Wilhelm Tischer; Volker Kasche

1999-01-01

147

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

148

ENZYMES OF THE LUNG  

PubMed Central

The esterases of rabbit lung have been investigated from two viewpoints, the cytochemical and the biochemical. To accomplish this objective, we designed and synthesized a series of ester substrates which provide both a cytochemical indicator of the location of the enzyme and a means of following the enzymatic activity in tissue homogenates and subfractions. The substrates are p-nitrophenylthiol esters which yield, upon hydrolysis, carboxylic acid and p-nitrothiophenol. The latter can react with aurous ions to give an electron-opaque deposit; in addition, the strong absorption of p-nitrothiophenol at 410 mµ permits continuous kinetic measurements. Thus, it is possible to correlate the intracellular site of action and the biochemical behavior of the esterases. The new substrates are the thiol analogues of the p-nitrophenyl esters frequently employed as esterase substrates. The rates of hydrolysis of the two series of esters are compared in vitro. During tissue fractionation, most of the esterase activity sediments with a particulate fraction. The effects of a number of common esterase inhibitors, such as diisopropyl phosphorofluoridate and eserine sulfate, are examined, and the effects of enzyme concentration and heat inactivation are shown with the use of the partially purified preparations. The cytochemical work shows that the esterase activity is most prominent in the lamellar bodies of the giant alveolar (type II, septal, or granular pneumatocyte) cells of the lung and to a lesser extent in squamous (type I, or membranous pneumatocyte) epithelial and endothelial cells. In both the cytochemical and biochemical studies, the enzymes are inhibited by diisopropyl phosphorofluoridate and phenyl methylsulfonyl fluoride but are insensitive to eserine sulfate.

Vatter, A. E.; Reiss, O. K.; Newman, Joyce K.; Lindquist, Karin; Groeneboer, Elly

1968-01-01

149

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

150

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.

McGuire, Grace; Falk, K. George

1920-01-01

151

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

152

Microbial Enzymes with Special Characteristics for Biotechnological Applications  

PubMed Central

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

Nigam, Poonam Singh

2013-01-01

153

Chloroperoxidase, a janus enzyme.  

PubMed

Chloroperoxidase is a versatile fungal heme-thiolate protein that catalyzes a variety of one-electron and two-electron oxidations. We report here that the alkylation of an essential histidine residue showed no effect on the one-electron peroxidations but inhibited two-electron oxidations. The pH profiles of different peroxidative substrates showed optimal activities at varying pH values for the same enzyme. 2-Allylphenol and substituted ortho-phenolics showed efficient peroxidations. Also, substrates excluded from the active site (or with no favorable positioning at the heme center or heme edge) were converted in the peroxidation reaction. While hydrogen peroxide serves as the superior activator in the two-electron oxidations, small alkylhydroperoxides give much better rates for peroxidation reactions. All the above observations indicate that one-electron oxidations are mechanistically quite different from the two-electron oxidations catalyzed by chloroperoxidase. We propose that the peroxidatic substrates interact predominantly outside the heme active site, presumably at the surface of the enzyme. PMID:18220360

Manoj, Kelath Murali; Hager, Lowell P

2008-03-01

154

The ACT: Preparing for the ACT, 2007-2008  

ERIC Educational Resources Information Center

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

ACT, Inc., 2007

2007-01-01

155

Deubiquitylating enzymes and disease  

PubMed Central

Deubiquitylating enzymes (DUBs) can hydrolyze a peptide, amide, ester or thiolester bond at the C-terminus of UBIQ (ubiquitin), including the post-translationally formed branched peptide bonds in mono- or multi-ubiquitylated conjugates. DUBs thus have the potential to regulate any UBIQ-mediated cellular process, the two best characterized being proteolysis and protein trafficking. Mammals contain some 80–90 DUBs in five different subfamilies, only a handful of which have been characterized with respect to the proteins that they interact with and deubiquitylate. Several other DUBs have been implicated in various disease processes in which they are changed by mutation, have altered expression levels, and/or form part of regulatory complexes. Specific examples of DUB involvement in various diseases are presented. While no specific drugs targeting DUBs have yet been described, sufficient functional and structural information has accumulated in some cases to allow their rapid development. Republished from Current BioData's Targeted Proteins database (TPdb; ).

Singhal, Shweta; Taylor, Matthew C; Baker, Rohan T

2008-01-01

156

Mental Health Parity and Addiction Equity Act  

MedlinePLUS

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

157

Clean Air Act 1990 Amendments  

SciTech Connect

This book is an analysis of the 1990 Amendments to the Clean Air Act that includes compliance requirements, the new operating permit system, the enhanced enforcement provisions and criminal penalties, potential for citizen enforcement, and the increased reporting requirements. Also analyzed are the new defenses such as permit compliance and protection of employees acting within the direction of employers.

Stensvaag, J.M.

1991-01-01

158

ENZYMES IN CANDIDA ALBICANS II.  

PubMed Central

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

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

1962-01-01

159

DGAT enzymes and triacylglycerol biosynthesis  

PubMed Central

Triacylglycerols (triglycerides) (TGs) are the major storage molecules of metabolic energy and FAs in most living organisms. Excessive accumulation of TGs, however, is associated with human diseases, such as obesity, diabetes mellitus, and steatohepatitis. The final and the only committed step in the biosynthesis of TGs is catalyzed by acyl-CoA:diacylglycerol acyltransferase (DGAT) enzymes. The genes encoding two DGAT enzymes, DGAT1 and DGAT2, were identified in the past decade, and the use of molecular tools, including mice deficient in either enzyme, has shed light on their functions. Although DGAT enzymes are involved in TG synthesis, they have distinct protein sequences and differ in their biochemical, cellular, and physiological functions. Both enzymes may be useful as therapeutic targets for diseases. Here we review the current knowledge of DGAT enzymes, focusing on new advances since the cloning of their genes, including possible roles in human health and diseases.

Yen, Chi-Liang Eric; Stone, Scot J.; Koliwad, Suneil; Harris, Charles; Farese, Robert V.

2008-01-01

160

Ethanologenic enzymes of Zymomonas mobilis  

SciTech Connect

In this study, we have proposed to investigate the mechanisms which permit the high level expression of the ethanologenic enzymes from Zymomonas mobilis (PDC, ADHI, ADHII). This research is continuing essentially as proposed in the original grant except that the scope has been expanded to include additional glycolytic enzymes from the lower portion of the Entner-Doudoroff pathway which are also highly expressed. Several enzymes which are expressed only at moderate levels are being examined for comparison (tryptophan biosynthesis, acid phosphatase).

Ingram, L.O.

1990-02-13

161

Psychrophilic enzymes: a thermodynamic challenge  

Microsoft Academic Search

Psychrophilic microorganisms, hosts of permanently cold habitats, produce enzymes which are adapted to work at low temperatures. When compared to their mesophilic counterparts, these enzymes display a higher catalytic efficiency over a temperature range of roughly 0–30°C and a high thermosensitivity. The molecular characteristics of cold enzymes originating from Antarctic bacteria have been approached through protein modelling and X-ray crystallography.

Charles Gerday; Mohamed Aittaleb; Jean Louis Arpigny; Etienne Baise; Jean-Pierre Chessa; Geneviève Garsoux; Ioan Petrescu; Georges Feller

1997-01-01

162

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

163

Bioaffinity Based Immobilization of Enzymes  

Microsoft Academic Search

Procedures that utilize the affinities of biomolecules and ligands for the immobilization of enzymes are gaining increasing\\u000a acceptance in the construction of sensitive enzyme-based analytical devices as well as for other applications. The strong\\u000a affinity of polyclonal\\/monoclonal antibodies for specific enzymes and those of lectins for glycoenzymes bearing appropriate\\u000a oligosaccharides have been generally employed for the purpose. Potential of affinity

M. Saleemuddin

164

Immobilized enzymes as analytical reagents  

Microsoft Academic Search

Immobilized enzymes are becoming increasingly popular as analytical reagents because of their reusability, stability, and\\u000a sensitivity to many inhibitors that would seriously interfere in assays using soluble enzymes. In this article, some of the\\u000a kinetic and catalytic effects of immobilized enzymes in analysis will be discussed. The shift of the activity-pH profile curves\\u000a on immobilization, the changes in temperature dependence.

George G. Guilbault

1982-01-01

165

Thermostable Enzymes in Lignocellulose Hydrolysis  

Microsoft Academic Search

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

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

166

Photoresponsive polymer-enzyme switches  

PubMed Central

The ability to photoregulate enzyme activities could provide important new opportunities for development of diagnostic assays, sequential bioprocessing, and lab assays in both traditional and microfluidic formats. We show here that the photoinduced changes in the size and hydration of a “smart” polymer chain coil can be used to regulate substrate access and enzyme activity when conjugated to the enzyme at a specific point just outside the active site. The photoresponsive polymers thus serve jointly as antennae and actuators that reversibly respond to distinct optical signals to switch the polymer–enzyme conjugates on and off, and work when the conjugate is free in solution or when immobilized on magnetic beads.

Shimoboji, Tsuyoshi; Larenas, Edmund; Fowler, Tim; Kulkarni, Samarth; Hoffman, Allan S.; Stayton, Patrick S.

2002-01-01

167

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

Code of Federal Regulations, 2010 CFR

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

2010-10-01

168

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

Code of Federal Regulations, 2010 CFR

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

2009-10-01

169

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

170

Entrapped Enzymes in Photocrosslinkable gel for Enzyme Electrodes  

Microsoft Academic Search

Enzyme sensors were prepared for the determination of glucose, ethanol, choline and acetylcholine by entrapment in photocrosslinkable PVA-SbQ gel. The determination is based on the electrochemical detection of enzymatically generated hydrogen peroxide. A linear response in a wide range of substrate concentrations and excellent storage stability were recorded for all enzymes tested.

J. L. Marty; N. Mionetto; R Rouillon

1992-01-01

171

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

172

Effect of vitamin E on glutathione-dependent enzymes.  

PubMed

Reactive oxygen species and various electrophiles are involved in the etiology of diseases varying from cancer to cardiovascular and pulmonary disorders. The human body is protected against damaging effects of these compounds by a wide variety of systems. An important line of defense is formed by antioxidants. Vitamin E (consisting of various forms of tocopherols and tocotrienols) is an important fat-soluble, chain-breaking antioxidant. Besides working as an antioxidant, this compound possesses other functions with possible physiological relevance. The glutathione-dependent enzymes form another line of defense. Two important enzymes in this class are the free radical reductase and glutathione S-transferases (GSTs). The GSTs are a family of phase II detoxification enzymes. They can catalyze glutathione conjugation with various electrophiles. In most cases the electrophiles are detoxified by this conjugation, but in some cases the electrophiles are activated. Antioxidants do not act in isolation but form an intricate network. It is, for instance, known that vitamin E, together with glutathione (GSH) and a membrane-bound heat labile GSH-dependent factor, presumably an enzyme, can prevent damaging effects of reactive oxygen species on polyunsaturated fatty acids in biomembranes (lipid peroxidation). This manuscript reviews the interaction between the two defense systems, vitamin E and glutathione-dependent enzymes. On the simplest level, antioxidants such as vitamin E have protective effects on glutathione-dependent enzymes; however, we will see that reality is somewhat more complicated. PMID:12959415

van Haaften, Rachel I M; Haenen, Guido R M M; Evelo, Chris T A; Bast, Aalt

2003-01-01

173

Magnetosensitive enzyme electrode for hydrogen peroxide sensing  

NASA Astrophysics Data System (ADS)

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

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

2003-05-01

174

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.

Schurmann, Marc; Deters, Anika; Wubbeler, Jan Hendrik

2013-01-01

175

An oxidative enzyme boosting the enzymatic conversion of recalcitrant polysaccharides.  

PubMed

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

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

2010-10-01

176

Flow-cell fibre-optic enzyme sensor for phenols  

SciTech Connect

A solid-state fibre-optic luminescent oxygen sensor was used for flow-through measurements. It acts as a transducer in a new flow-cell enzyme sensor arrangement. This arrangement comprises a flow path, sample injector, microcolumn with the immobilized enzyme, oxygen membrane and fibre-optic connector joined together to form an integral unit. Laccase enzyme was used as a recognition system which provided specific oxidation of the substrates with the dissolved oxygen being monitored. The assay procedure was optimized and performance of the new system studied. The sensor was applied to the determination polyphenol content in tea, brandy, etc. (quality control test). The sensitivity to some important phenolic compounds was tested with the view of industrial wastewater control applications. 5 refs., 6 figs., 1 tab.

Papkovsky, D.B.; Ghindilis, A.L.; Kurochkin, I.N. (Research Center of Molecular Diagnostics and Therapy, Moscow (Russian Federation))

1993-07-01

177

Salivary enzymes and periodontal disease  

Microsoft Academic Search

Background: Host responses to periodontal disease include the production of different enzymes that are released by stromal, epithelial or inflammatory cells. There are important enzymes associated with cell injury and cell death like: aspartate and alanine aminotransferase (AST, ALT), lactate dehydrogenase (LDH), creatine cinase (CK), alkaline and acidic phosphatase (ALP, ACP), gama glutamil transferase (GGT). Changes in enzymatic activity reflect

Tatjana Todorovic; Ivan Dozic; Mario Vicente Barrero; Besir Ljuskovic; Janko Pejovic; Marjan Marjanovic

178

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

179

Enzymic Iodination of Milk Proteins  

Microsoft Academic Search

RECENTLY, Pitney and Russell Fraser1 have reported studies in which they utilized, as a model system for antithyroid drug evaluation, a procedure based on that of Keston2 for the enzymic iodination of milk proteins. This has prompted us to outline some of our observations with a similar system using purified milk enzymes and proteins. Native casein in a finely suspensible

Mary T. McQuillan; R. K. Morton; P. G. Stanley; V. M. Trikojus

1954-01-01

180

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.

University Of Houston

181

Enzyme Catalysis in Organic Synthesis  

Microsoft Academic Search

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

K. Martinek; A. N. Semenov

1981-01-01

182

Collagen-Immobilized Enzyme Systems.  

National Technical Information Service (NTIS)

Methods of preparation of collagen-enzyme and collagen-whole cells membranes are outlined. Procedures for the determination of (a) activity of the conjugated preparations, (b) amount of bound enzyme, (c) stability, and (d) kinetic and mass-transfer parame...

W. R. Vieth K. Venkatasubramanian

1975-01-01

183

Immobilized enzyme reactors in proteomics  

Microsoft Academic Search

Fast, efficient characterization of proteins is becoming one of the hottest topics in the bioanalytical community, especially for large-scale proteomic studies. As an attractive approach, protein digestion by enzymes supported on various matrices (referred to as immobilized enzyme reactors, IMERs) has recently attracted much attention.In this article, we present a critical overview of some highly efficient IMERs and related analytical

Junfeng Ma; Lihua Zhang; Zhen Liang; Yichu Shan; Yukui Zhang

2011-01-01

184

Engineering of Immobilized Enzyme Systems  

Microsoft Academic Search

The advent of enzyme immobilization, allowing re-use of enzymes, and essentially eliminating product contamination, has greatly increased the potential of enzymatic processes for industrial use. Although this is a relatively new field of study, the literature is rapidly expanding. The compendium of references prepared by the New England Research Applications Center for Corning Glass Works now lists over 800 papers

Wayne H. Pitcher Jr

1975-01-01

185

Targeting Inactive Enzyme Conformation  

PubMed Central

There has been considerable interest in protein tyrosine phosphatase 1B (PTP1B) as a therapeutic target for diabetes, obesity, as well as cancer. Identifying inhibitory compounds with good bioavailability is a major challenge of drug discovery programs targeted toward PTPs. Most current PTP active site-directed pharmacophores are negatively charged pTyr mimetics which cannot readily enter the cell. This lack of cell permeability limits the utility of such compounds in signaling studies and further therapeutic development. We identify aryl diketoacids as novel pTyr surrogates and show that neutral amide-linked aryl diketoacid dimers also exhibit excellent PTP inhibitory activity. Kinetic studies establish that these aryl diketoacid derivatives act as noncompetitive inhibitors of PTP1B. Crystal structures of ligand-bound PTP1B reveal that both the aryl diketoacid and its dimeric derivative bind PTP1B at the active site, albeit with distinct modes of interaction, in the catalytically inactive, WPD loop open conformation. Furthermore, dimeric aryl diketoacids are cell permeable and enhance insulin signaling in hepatoma cells, suggesting that targeting the inactive conformation may provide a unique opportunity for creating active site-directed PTP1B inhibitors with improved pharmacological properties.

Liu, Sijiu; Zeng, Li-Fan; Wu, Li; Yu, Xiao; Xue, Ting; Gunawan, Andrea M.; Ya-Qiu, Long; Zhang, Zhong-Yin

2009-01-01

186

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

1990-01-01

187

Positron emitter labeled enzyme inhibitors  

DOEpatents

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

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

1987-05-22

188

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

189

Extracellular Hydrolytic Enzymes of Rabbit Dermal Tuberculous Lesions and Tuberculin Reactions Collected in Skin Chambers  

PubMed Central

To evaluate extracellular hydrolytic enzymes in an in vivo system, plastic chambers were glued over rabbit dermal BCG lesions in various stages of development, after the central epithelium was removed with a scalpel. They were filled with tissue culture medium and left in place 2 days. The following enzymes in the fluid were assayed: collagenase (an enzyme secreted but not stored in macrophages); lysozyme (both secreted and stored); DNase and RNase (released on cell death and possibly regurgitated but not secreted); and, as a control, lactic dehydrogenase (released only on cell death). Tissue sections were prepared and studied histologically for the type of cell infiltrate, for ?-galactosidase (our marker enzyme for macrophage activation), and for necrosis. At 11 and 18 days of age the BCG lesions were largest and the number of activated macrophages in the chamber beds was highest. At this time the levels of the five enzymes assayed in the chamber fluids reached their peaks, tuberculin hypersensitivity was well developed, and the bacilli components would still be plentiful. In general, the chamber fluids from 11- and 18-day BCG lesions contained higher enzyme levels than chamber fluids from tuberculin reactions. Active collagenase was only detected in fluids from such BCG lesions. Evidently, the serum in the chamber fluids was sufficient to inhibit the lower amounts of collagenase probably released from smaller BCG lesions and tuberculin reactions (and from the 2-week polystyrene lesions that were also evaluated). These studies demonstrate that in chronic inflammatory reactions, both acid-acting and neutral-acting hydrolytic enzymes are released extracellularly. Tissue components would be hydrolyzed locally wherever the acid-acting hydrolytic enzymes encounter a drop in pH and wherever the concentration of neutral-acting hydrolytic enzymes exceeds the concentration of their inhibitors. ImagesFigure 1Figure 2

Sugimoto, Mineharu; Dannenberg, Arthur M.; Wahl, Larry M.; Ettinger, Walter H.; Hastie, Annette T.; Daniels, David C.; Thomas, Christopher R.; Demoulin-Brahy, Lucie

1978-01-01

190

Analysis of recombinant yeast decapping enzyme  

PubMed Central

A critical step in the turnover of yeast mRNAs is decapping. Two yeast proteins, Dcp1p and Dcp2p, are absolutely required for decapping, although their precise roles in the decapping reaction have not been established. To determine the function of both Dcp1p and Dcp2p in decapping, we purified recombinant versions of these proteins from Escherichia coli and examined their properties. These experiments demonstrate that copurification of Dcp1p and Dcp2p yields active decapping enzyme under a variety of conditions. Moreover, Dcp2p alone can have decapping activity under some biochemical conditions. This suggests that Dcp2p can be a catalytic subunit of the decapping complex, and Dcp1p may function to enhance Dcp2p activity, or as an additional active subunit. In addition, recombinant Dcp1p/Dcp2p prefers long mRNA substrates and is sensitive to inhibition by sequestration of the 5? end but not the 3? end of the substrate. This suggests that Dcp1p/Dcp2p contains an additional RNA-binding site spatially distinct from the active site. Finally, using two RNA-binding proteins that enhance decapping in vivo (Edc1p and Edc2p), we can reconstitute the activation of decapping with recombinant proteins. This indicates that the Edc1 and Edc2 proteins act directly on the decapping enzyme.

STEIGER, MICHELLE; CARR-SCHMID, ANNE; SCHWARTZ, DAVID C.; KILEDJIAN, MEGERDITCH; PARKER, ROY

2003-01-01

191

Superfund Reform Act of 1994  

SciTech Connect

The legislation which would amend the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), was developed through a lengthy process that capitalized on the expertise of the many Superfund stakeholders -- both inside and outside of government.

Not Available

1994-02-01

192

Hatch Act Reform - Unresolved Questions.  

National Technical Information Service (NTIS)

In recent years the Congress has considered several bills to reform the Hatch Act prohibiting Government employees from participating in partisan political activity. Generally, these bills would have reduced the restriction on partisan political activity ...

1979-01-01

193

Freedom of Information Act Report  

NSF Publications Database

... OF INFORMATION ACT REPORT FOR OCTOBER 1, 1997 THROUGH SEPTEMBER 30, 1998 I. BASIC INFORMATION: A ... and/or proprietary information; for records containing information compiled for law enforcement ...

194

Update: the Clean Water Act  

Microsoft Academic Search

The Clean Water Act--officially labeled Public Law 92-500, The Federal Water Pollution Control Act Amendments of 1972--established a national permit discharge elimination system (NPDES) to control the discharge of pollutants into the nation's waters and set strict enforcement deadlines to be complied with by July 1, 1977. The ''best available'' technology (BAT) that is economically achievable must be used by

Meinhold

1977-01-01

195

Brain drug-metabolizing cytochrome P450 enzymes are active in vivo, demonstrated by mechanism-based enzyme inhibition.  

PubMed

Individuals vary in their response to centrally acting drugs, and this is not always predicted by drug plasma levels. Central metabolism by brain cytochromes P450 (CYPs) may contribute to interindividual variation in response to drugs. Brain CYPs have unique regional and cell-type expression and induction patterns, and they are regulated independently of their hepatic isoforms. In vitro, these enzymes can metabolize endogenous and xenobiotic substrates including centrally acting drugs, but there is no evidence to date of their in vivo function. This has been difficult to demonstrate in the presence of hepatically derived metabolites that may cross the blood-brain barrier. In addition, because of the membrane location of brain CYPs and the rate limiting effect of endogenous heme levels on the activity and appropriate membrane insertion of some induced CYPs, it has been unclear whether sufficient cofactors and coenzymes are present for constitutive and induced CYP forms to be enzymatically active. We have developed a method using a radiolabeled mechanism-based inhibitor of CYP2B1, (3)H-8-methoxypsoralen, to demonstrate for the first time that both the constitutive and induced forms of this enzyme are active in situ in the living rat brain. This methodology provides a novel approach to assess the function of enzymes in extrahepatic tissues, where expression levels are often low. Selective induction of metabolically active drug metabolizing enzymes in the brain may also provide ways to control prodrug activation in specific brain regions as a novel therapeutic avenue. PMID:18668033

Miksys, Sharon; Tyndale, Rachel F

2009-02-01

196

Glycogenolytic enzymes in sporulating yeast.  

PubMed Central

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

Colonna, W J; Magee, P T

1978-01-01

197

Enzyme inhibiting compounds and methods  

US Patent & Trademark Office Database

The invention provides compounds, compositions, and methods for studying the Rohmer pathway and for treating bacterial infections or parasitic infections. The parasitic infection can be a protozoan infection, such as malaria. The compounds and compositions can also be used as antibiotics, for example, to kill bacteria or parasites, or to inhibit bacterial or parasite growth. The invention further provides inhibitors of isoprenoid biosynthesis enzymes, and methods of inhibiting the activity of isoprenoid biosynthesis enzymes. The compounds can be, for example, alkynes or allenes that bind to a unique Fe of an Fe4S4 cluster of an isoprenoid biosynthesis enzyme.

2013-12-17

198

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

199

Nanoporous gold for enzyme immobilization.  

PubMed

Nanoporous gold (NPG) is a material of emerging interest for immobilization of biomolecules and -especially enzymes. NPG materials provide a high gold surface area onto which biomolecules can either be directly physisorbed or covalently linked after first modifying the NPG with a self-assembled monolayer. The material can be used as a high surface area electrode and with immobilized enzymes can be used for amperometric detection schemes. NPG can be prepared in a variety of formats from alloys containing less than 50 atomic% gold by dealloying procedures. Related high surface area gold structures have been prepared using templating approaches. Covalent enzyme immobilization can be achieved by first forming a self-assembled monolayer on NPG bearing a terminal reactive functional group followed by conjugation to the enzyme through amide linkages to lysine residues. PMID:20865389

Stine, Keith J; Jefferson, Kenise; Shulga, Olga V

2011-01-01

200

The origins of enzyme kinetics.  

PubMed

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

Cornish-Bowden, Athel

2013-09-01

201

In vitro evolution of enzymes.  

PubMed

In the past decade, in vitro evolution techniques have been used to improve the performance or alter the activity of a number of different enzymes and have generated enzymes de novo. In this review, we provide an overview of the available in vitro methods, their application, and some general considerations for enzyme engineering in vitro. We discuss the advantages of in vitro over in vivo approaches and focus on ribosome display, mRNA display, DNA display technologies, and in vitro compartmentalization (IVC) methods. This review aims to help researchers determine which approach is best suited for their own experimental needs and to highlight that in vitro methods offer a promising route for enzyme engineering. PMID:23423890

Golynskiy, Misha V; Haugner, John C; Morelli, Aleardo; Morrone, Dana; Seelig, Burckhard

2013-01-01

202

Enzyme immobilisation in permselective microcapsules.  

PubMed

The objective of this investigation was to study the permselective behaviour of calcium alginate membranes, including the modifying effects of silica additives, which were subsequently used as microcapsule shells. Diffusion experiments and HPLC were carried out to ascertain the size-exclusion property of the membranes for a mixed molecular-weight dextran solution. Hollow microcapsules containing the enzyme dextranase were prepared using double concentric nozzles and the encapsulation performance was evaluated based on an analysis of the enzyme reactivity and stability. To improve mass transport within the microcapsules, magnetic nanoparticles were introduced into the liquid core and agitated using an alternating external magnetic field. The modified membranes exhibited better size-exclusion behaviour than the unmodified membranes. The magnetic nanoparticles slightly improved mass transport inside the microcapsule. The encapsulated enzyme yielded nearly 80% of the free enzyme activity and retained about 80% of the initial catalytic activity even after being used for eight reaction cycles. PMID:21736522

Pachariyanon, Pavadee; Barth, Ekkehard; Agar, David W

2011-01-01

203

Electrical Microengineering of Redox Enzymes.  

National Technical Information Service (NTIS)

Enzymes made of electrically insulating proteins were made electron conducting through incorporation of electron relaying redox centers. The redox centers were covalently bound to amino acids of proteins, particularly to lysine amines, 1,2 or to periphera...

A. Heller

1994-01-01

204

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

205

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

Microsoft Academic Search

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

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

2008-01-01

206

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.

2013-01-01

207

[Proteolytic enzymes and their inhibitors].  

PubMed

Tryptase (T), chymase (C), carboxypeptidase A, cathepsin G-like constituent of preformed mediators contained in mastocyte granules, are a group of neutral proteases with proteolytic activity. These enzymes gives differentiation of two groups of mastocytes, MCTC and MCT as a function of the richness of enzymes. Although the functions of these molecules are becoming better and better understood, their exact roles as well as that of their inhibitors, still remain to be explored in urticaria. PMID:8216729

Koeppel, M C; Sayag, J

1993-09-01

208

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

209

SOME ENZYMES OF ISOLATED NUCLEI  

PubMed Central

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

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

1952-01-01

210

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Did the 1998 Act repeal the 1965 Act? 51.101 Section... CONCESSION CONTRACTS The Effect of the 1998 Act's Repeal of the 1965 Act § 51.101 Did the 1998 Act repeal the 1965 Act? Section 415...

2010-07-01

211

Foreign Corrupt Practices Act Fundamentals  

Microsoft Academic Search

Foreign Corrupt Practices Act (FCPA) enforcement activity is currently at its highest level since enactment of the statute in 1977. There were more enforcement actions brought in 2007 than in the years from 2004 to 2006 combined. The message is clear - the U.S. Government is committed to FCPA compliance and there is no evidence enforcement activity will slow any

Jessica Tillipman

2008-01-01

212

Endangered Species Act of 1973.  

National Technical Information Service (NTIS)

The purposes of this Act are to provide a means whereby the ecosystems upon which endangered species and threatened species depend may be conserved, to provide a program for the conservation of such endangered species and threatened species, and to take s...

2004-01-01

213

Revising the War Powers Act  

Microsoft Academic Search

The issues that prompted the passing of the War Powers Act will continue to bedevil us again if Congress does not prepare to meet the future with seriously asserted procedures to regularize its relationship to the executive branch regarding a recourse to arms.There were unintended ambiguities and unforeseen exigencies in the original war powers legislation that have confounded systematic application

James A. Nathan

1991-01-01

214

Clean Water Act amendments debated  

Microsoft Academic Search

A short discussion of the debate taking place between Congress, industry and environmental groups with respect to the amendments to the Clean Water Act is presented. The discussion considers the EPA proposal, the reaction to it, and the prognosis for passage. (KRM)

Deland

1982-01-01

215

Identification of a selective nuclear import signal in adenosine deaminases acting on RNA  

Microsoft Academic Search

The adenosine deaminases acting on RNA (ADARs) comprise a family of RNA editing enzymes that selectively modify single codons within RNA primary transcripts with often profound impact on protein function. Little is known about the mechanisms that regulate nuclear RNA editing activity. Editing levels show cell-type specific and developmental modulation that does not strictly coincide with observed expression levels of

Stefan Maas; Willemijn M. Gommans

2009-01-01

216

Rethinking fundamentals of enzyme action.  

PubMed

Despite certain limitations, investigators continue to gainfully employ concepts rooted in steady-state kinetics in efforts to draw mechanistically relevant inferences about enzyme catalysis. By reconsidering steady-state enzyme kinetic behavior, this review develops ideas that allow one to arrive at the following new definitions: (a) V/K, the ratio of the maximal initial velocity divided by the Michaelis-Menten constant, is the apparent rate constant for the capture of substrate into enzyme complexes that are destined to yield product(s) at some later point in time; (b) the maximal velocity V is the apparent rate constant for the release of substrate from captured complexes in the form of free product(s); and (c) the Michaelis-Menten constant K is the ratio of the apparent rate constants for release and capture. The physiologic significance of V/K is also explored to illuminate aspects of antibiotic resistance, the concept of "perfection" in enzyme catalysis, and catalytic proficiency. The conceptual basis of congruent thermodynamic cycles is also considered in an attempt to achieve an unambiguous way for comparing an enzyme-catalyzed reaction with its uncatalyzed reference reaction. Such efforts promise a deeper understanding of the origins of catalytic power, as it relates to stabilization of the reactant ground state, stabilization of the transition state, and reciprocal stabilizations of ground and transition states. PMID:10218105

Northrop, D B

1999-01-01

217

Acting Out; Theoretical and Clinical Aspects.  

ERIC Educational Resources Information Center

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

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

218

75 FR 7312 - No FEAR Act Notice  

Federal Register 2010, 2011, 2012, 2013

...TENNESSEE VALLEY AUTHORITY No FEAR Act Notice Summary: 5 CFR part 724.202...initial notice in the Federal Register. No FEAR Act Notice On May 15, 2002, Congress...of 2002, which is now known as the No FEAR Act. One purpose of the Act is to...

2010-02-18

219

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

220

Enzyme-based listericidal nanocomposites.  

PubMed

Cell lytic enzymes represent an alternative to chemical decontamination or use of antibiotics to kill pathogenic bacteria, such as listeria. A number of phage cell lytic enzymes against listeria have been isolated and possess listericidal activity; however, there has been no attempt to incorporate these enzymes onto surfaces. We report three facile routes for the surface incorporation of the listeria bacteriophage endolysin Ply500: covalent attachment onto FDA approved silica nanoparticles (SNPs), incorporation of SNP-Ply500 conjugates into a thin poly(hydroxyethyl methacrylate) film; and affinity binding to edible crosslinked starch nanoparticles via construction of a maltose binding protein fusion. These Ply500 formulations were effective in killing L. innocua (a reduced pathogenic surrogate) at challenges up to 10(5)?CFU/ml both in non-growth sustaining PBS as well as under growth conditions on lettuce. This strategy represents a new route toward achieving highly selective and efficient pathogen decontamination and prevention in public infrastructure. PMID:23545700

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

2013-01-01

221

Angiotensin converting enzyme inhibitor therapy.  

PubMed

Angiotensin converting enzyme inhibitor therapy decreases the production of the vasoconstrictive angiotensin II and reduces the degradation of certain kinines of vasodilatator action. Of captopril, enalapril, and lysinopril marketed abroad, only captopril of shorter action is available in Hungary. Angiotensin converting enzyme inhibitors are new means for the therapy of hypertension and congestive heart failure. Captopril seems to be effective at an early stage of heart failure. It slows down or even inhibits the progression of heart failure. New aspects of therapy have been revealed. It may be successfully used in angina pectoris, for the prevention of reperfusion arrhythmias accompanying myocardial infarction, for the treatment of renoparenchimal renal diseases, diabetic nephropathy. The side-effects, interactions, and dosage of angiotensin converting enzyme inhibitors have also been discussed. PMID:1948779

Róna, G

1991-01-01

222

Peroxiredoxin 5 from common cutworm (Spodoptera litura) acts as a potent antioxidant enzyme.  

PubMed

In this study, we describe the cloning and characterization of a Prx from the common cutworm Spodoptera litura (SlPrx5). The SlPrx5 cDNA contains an open reading frame of 477bp encoding a predicted protein of 159 amino acid residues, 16.902kDa, and an isoelectric point of 7.68. Furthermore, the deduced amino acid sequence of the SlPrx5 cDNA showed 86% identity to Papilio xuthus Prx5, 72% to Aedes aegypti Prx5, and 64-67% to other insect Prxs. A phylogenetic analysis further revealed that the deduced amino acid sequence of SlPrx5 groups within the atypical 2-Cys Prx cluster. Recombinant SlPrx5 (20kDa) purified from baculovirus-infected insect cells was found to reduce H2O2 in the presence of electrons donated by dithiothreitol and protect super-coiled DNA from damage by metal-catalyzed oxidation in vitro. During S. litura development, SlPrx5 is constitutively expressed in the epidermis, fat body, and midgut, with the highest expression occurring in the sixth-instar larval stage in the fat body and midgut. Additionally, SlPrx5 mRNA expression was up-regulated after injection with H2O2, cumene hydroperoxide, indoxacarb, and metaflumizone. A disc diffusion assay indicated that recombinant SlPrx5 can play a functional role in protecting cells from oxidative stress in vivo. These results provide insight into the role of SlPrx5 during development and the oxidative stress response of S. litura. PMID:24998343

Wan, Hu; Kang, Tinghao; Zhan, Sha; You, Hong; Zhu, Fuxing; Lee, Kwang Sik; Zhao, Haigang; Jin, Byung Rae; Li, Jianhong

2014-09-01

223

Enzyme-linked enzyme binding assay for Pin1 WW domain ligands  

PubMed Central

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

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

2010-01-01

224

Nickel-based Enzyme Systems*  

PubMed Central

Of the eight known nickel enzymes, all but glyoxylase I catalyze the use and/or production of gases central to the global carbon, nitrogen, and oxygen cycles. Nickel appears to have been selected for its plasticity in coordination and redox chemistry and is able to cycle through three redox states (1+, 2+, 3+) and to catalyze reactions spanning ?1.5 V. This minireview focuses on the catalytic mechanisms of nickel enzymes, with an emphasis on the role(s) of the metal center. The metal centers vary from mononuclear to complex metal clusters and catalyze simple hydrolytic to multistep redox reactions.

Ragsdale, Stephen W.

2009-01-01

225

Macromolecular juggling by ubiquitylation enzymes.  

PubMed

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

Lorenz, Sonja; Cantor, Aaron J; Rape, Michael; Kuriyan, John

2013-01-01

226

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

227

Taking the Mystery Out of Enzymes.  

ERIC Educational Resources Information Center

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

DeYoung, H. Garrett

1984-01-01

228

78 FR 42802 - Notice of Lodging of Proposed Consent Decree Under the Clean Water Act, Clean Air Act, and...  

Federal Register 2010, 2011, 2012, 2013

...Decree Under the Clean Water Act, Clean Air Act, and Resource Conservation and Recovery Act On July 11, 2013...L.C. under the Clean Water Act, Clean Air Act, and Resource Conservation and Recovery Act. The United...

2013-07-17

229

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

Code of Federal Regulations, 2013 CFR

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

2013-04-01

230

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.

231

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

232

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

233

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

234

Enzyme-enabled responsive surfaces for anti-contamination materials.  

PubMed

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

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

2013-06-01

235

Thermodynamics of Enzyme-Catalyzed Reactions Database  

National Institute of Standards and Technology Data Gateway

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

236

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

Microsoft Academic Search

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

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

2003-01-01

237

The principles of guiding by RNA: chimeric RNA–protein enzymes  

Microsoft Academic Search

The non-protein-coding transcriptional output of the cell is far greater than previously thought. Although the functions, if any, of the vast majority of these RNA transcripts remain elusive, out of those for which functions have already been established, most act as RNA guides for protein enzymes. Common features of these RNAs provide clues about the evolutionary constraints that led to

Peter Schattner; Alexander Hüttenhofer

2006-01-01

238

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

239

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

240

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

241

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

242

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

243

Enzyme encapsulation on chitosan microbeads  

Microsoft Academic Search

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

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

1997-01-01

244

Enzyme recovery using reversed micelles  

Microsoft Academic Search

The objective of this study was to develop a liquid-liquid extraction process for the recovery of extracellular enzymes. The potentials of reaching this goal by using reversed micelles in an organic solvent have been investigated.Reversed micelles are aggregates of surfactant molecules containing an inner core of water molecules, dispersed in a continuous organic solvent medium. The considerable biotechnological potential of

1990-01-01

245

The Angiotensin I Converting Enzyme.  

National Technical Information Service (NTIS)

The angiotensin I converting enzyme (kininase II; peptidyl dipeptidase; EC 3.4. 15.1) has a dual function: it converts angiotensin I to angiotensin II and it inactivates bradykinin. Lung, kidney, guinea pig plasma and testicles are among the richest sourc...

E. G. Erdos

1977-01-01

246

ENZYME BIOSYNTHESIS IN ESCHERICHIA COLI  

PubMed Central

Escherichia coli B synthesized ?-galactosidase and an enzyme system for D-xylose when exposed to lactose and xylose respectively in nitrogen-free media. The amount of ?-galactosidase formed in the absence of external nitrogen depended upon the nature of the medium in which the cells had originally been grown. Half as much of this enzyme was synthesized without exogenous nitrogen by cells taken from a nitrogen-rich medium as was formed by cells under favorable conditions with an external supply of nitrogen. Escherichia coli B contained a pool of nitrogen compounds soluble in 80 per cent ethanol and made up of several ninhydrin-positive components. One of these was identified chromatographically as glycine using an authentic radioactive sample. Another substance behaved like serine on the chromatograms. The internal pool of amino acids and peptides was large enough to account for the ?-galactosidase synthesized by cells exposed to lactose in a medium free of nitrogen. Some degree of interaction of the syntheses of the ?-galactosidase and xylose enzyme systems was observed in nitrogen-free media. This interaction produced a greater effect on the formation of ?-galactosidase and was attributed to a limiting factor(s) in the internal nitrogenous pool or to a limiting intermediate in enzyme synthesis.

Weinbaum, George; Mallette, M. F.

1959-01-01

247

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

248

Organoclay-enzyme film electrodes  

Microsoft Academic Search

This paper aims at showing the interest of organoclays (clay minerals containing organic groups covalently attached to the inorganic particles) as suitable host matrices likely to immobilize enzymes onto electrode surfaces for biosensing applications. The organoclays used in this work were natural Cameroonian smectites grafted with either aminopropyl (AP) or trimethylpropylammonium (TMPA) groups. The first ones were exploited for their

Justin Kemmegne Mbouguen; Emmanuel Ngameni; Alain Walcarius

2006-01-01

249

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

250

Enzymes for Polymer Surface Modification  

Microsoft Academic Search

During the recent years, various bacteria and fungi have been investigated concerning their ability to degrade artificial\\u000a polymers. This chapter reviews recent work on enzymes used for hydrolysis\\/oxidation of synthetic polymers and discusses their\\u000a use in polymer surface modification.

G. Fischer-Colbrie; S. Heumann; G. Guebitz

251

Quantitative Comparison of Catalytic Mechanisms and Overall Reactions in Convergently Evolved Enzymes: Implications for Classification of Enzyme Function  

PubMed Central

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

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

2010-01-01

252

32 CFR 324.14 - Relationship between the Privacy Act and the Freedom of Information Act.  

Code of Federal Regulations, 2013 CFR

...Relationship between the Privacy Act and the Freedom of Information Act. 324.14 Section...Relationship between the Privacy Act and the Freedom of Information Act. Access requests...FOIA, are processed pursuant to the DFAS Freedom of Information Act Regulation....

2013-07-01

253

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 2543... Clean Air Act and the Federal Water Pollution Control Act. Contracts and subgrants...7401 et seq. ) and the Federal Water Pollution Control Act as amended (33...

2013-10-01

254

Angiotensin converting enzyme 2 in the brain  

PubMed Central

Angiotensin (Ang) converting enzyme (ACE) 2 cleaves Ang-II into the vasodilator peptide Ang-(1-7), thus acting as a pivotal element in balancing the local effects of these peptides. ACE2 has been identified in various tissues and is supposed to be a modulator of cardiovascular function. Decreases in ACE2 expression and activity have been reported in models of hypertension, heart failure, atherosclerosis, diabetic nephropathy and others. In addition, the expression level and/or activity are affected by other renin-angiotensin system components (e.g. ACE and AT1 receptors). Local inhibition or global deletion of brain ACE2 induces a reduction in baroreflex sensitivity. Moreover, ACE2-null mice have been shown to exhibit either blood pressure (BP) or cardiac dysfunction phenotypes. On the other hand, over-expression of ACE2 exerts protective effects in local tissues, including the brain. In this review, we will first summarize the major findings linking ACE2 to cardiovascular function in the periphery then focus on recent discoveries related to ACE2 in the central nervous system. Finally, we will unveil new tools designed to address the importance of central ACE2 in various diseases, and discuss the potential for this carboxypeptidase as a new target in the treatment of hypertension and other cardiovascular diseases.

Xia, Huijing; Lazartigues, Eric

2009-01-01

255

Progress in the Studies of Enzyme Immobilization and Applications of Immobilized Enzyme  

Microsoft Academic Search

Enzyme immobilization benefits the separation of reactant from enzyme and the reuse of enzyme. Some research developments on enzyme immobilization including the methods, functional groups useful for immobilization and mass transfer effect are reviewed. Some applications of immobilized enzyme on biosensor, organic reaction and environmental protection have also been discussed.

Diao Yinghui; Fu Shiyu; Yu Huisheng

256

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

PubMed Central

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.

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

1985-01-01

257

The Advanced Communications Technology Satellite (ACTS): Five new technologies  

NASA Astrophysics Data System (ADS)

The topics are presented in viewgraph form and include the following: ACTS program objectives; an overview of ACTS flight segment; an overview of ACTS ground segment; spacecraft configuration; ACTS spacecraft characteristics; ACTS new technologies; ACTS multibeam communication system block diagram; ACTS multibeam antenna characteristics; ACTS multibeam antenna coverage; electronically hopping beams; on-board switching; baseband processor mode; microwave switch matrix mode; Ka-band transponder characteristics; rain fade compensation; propagation beacons; ACTS spacecraft status; ACTS experimenter terminal categories; and ACTS system operations.

Gargione, F.

258

Targeting enzymes for cancer therapy: old enzymes in new roles  

Microsoft Academic Search

Enzymes which traditionally have played no role in cell-directed cytotoxicity are finding their way into schemes for prodrug activation and immunotoxins owing to such useful enzymatic activity. Alkaline phosphatase, carboxypeptidases, beta-glucosidases and beta-lactamases among many others are being utilised to regenerate potent anti-cancer drugs or toxic small molecules from precursors in a bid to enhance their activity in tumours. These

MP Deonarain; AA Epenetos

1994-01-01

259

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

260

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

PubMed

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

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

2014-07-01

261

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

262

Speech Act Theory and Business Communication Conventions.  

ERIC Educational Resources Information Center

Applies speech act theory to business writing to determine why certain letters and memos succeed while others fail. Specifically, shows how speech act theorist H. P. Grice's rules or maxims illuminate the writing process in business communication. (PD)

Ewald, Helen Rothschild; Stine, Donna

1983-01-01

263

34 CFR 303.4 - Act.  

Code of Federal Regulations, 2013 CFR

...OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION EARLY INTERVENTION PROGRAM FOR INFANTS AND TODDLERS WITH DISABILITIES General Definitions Used in This Part § 303.4 Act. Act means the Individuals with...

2013-07-01

264

Estuaries and Clean Water Act of 2000  

NSDL National Science Digital Library

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

265

Government in the Sunshine Act, 2006.  

National Technical Information Service (NTIS)

In the early 1970s, partially in response to the Watergate scandal, Congress enacted the Government in the Sunshine Act along with other anti-secrecy legislation. Congress intended the Sunshine Act to open the government's deliberation processes to public...

2007-01-01

266

76 FR 65758 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013

...financial system. The new Advisers Act rule would implement sections 404 and 406 of the Dodd-Frank Act. Commissioner Paredes, as duty officer, determined that no earlier notice thereof was possible. At times, changes in Commission priorities...

2011-10-24

267

Dialogue Act Recognition using Reweighted Speaker Adaptation.  

National Technical Information Service (NTIS)

In this work we study the effectiveness of speaker adaptation for dialogue act recognition in multiparty meetings. First, we analyze idiosyncracy in dialogue verbal acts by qualitatively studying the differences and conflicts among speakers and by quantit...

C. Sun L. Morency

2012-01-01

268

30 CFR Relief - Act Deep Water Leases  

Code of Federal Regulations, 2010 CFR

...1999-07-01 1999-07-01 false Act Deep Water Leases Relief Royalty Relief For Deep Water Expansion Projects And Pre Mineral Resources...lease assignment. Royalty Relief For Deep Water Expansion Projects And Pre-Act Deep...

1999-07-01

269

30 CFR Relief - Act Deep Water Leases  

Code of Federal Regulations, 2010 CFR

...1998-07-01 1998-07-01 false Act Deep Water Leases Relief Royalty Relief For Deep Water Expansion Projects And Pre ROYALTY MANAGEMENT...lease assignment. Royalty Relief For Deep Water Expansion Projects And Pre-Act Deep...

1998-07-01

270

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

271

Localization of enzymes within microbodies.  

PubMed

Microbodies from rat liver and a variety of plant tissues were osmotically shocked and subsequently centrifuged at 40,000 g for 30 min to yield supernatant and pellet fractions. From rat liver microbodies, all of the uricase activity but little glycolate oxidase or catalase activity were recovered in the pellet, which probably contained the crystalline cores as many other reports had shown. All the measured enzymes in spinach leaf microbodies were solubilized. With microbodies from potato tuber, further sucrose gradient centrifugation of the pellet yielded a fraction at density 1.28 g/cm(3) which, presumably representing the crystalline cores, contained 7% of the total catalase activity but no uricase or glycolate oxidase activity. Using microbodies from castor bean endosperm (glyoxysomes), 50-60% of the malate dehydrogenase, fatty acyl CoA dehydrogenase, and crotonase and 90% of the malate synthetase and citrate synthetase were recovered in the pellet, which also contained 96% of the radioactivity when lecithin in the glyoxysomal membrane had been labeled by previous treatment of the tissue with [(14)C]choline. When the labeled pellet was centrifuged to equilibrium on a sucrose gradient, all the radioactivity, protein, and enzyme activities were recovered together at peak density 1.21-1.22 g/cm(3), whereas the original glyoxysomes appeared at density 1.24 g/cm(3). Electron microscopy showed that the fraction at 1.21-1.22 g/cm(3) was comprised of intact glyoxysomal membranes. All of the membrane-bound enzymes were stripped off with 0.15 M KCl, leaving the "ghosts" still intact as revealed by electron microscopy and sucrose gradient centrifugation. It is concluded that the crystalline cores of plant microbodies contain no uricase and are not particularly enriched with catalase. Some of the enzymes in glyoxysomes are associated with the membranes and this probably has functional significance. PMID:4729505

Huang, A H; Beevers, H

1973-08-01

272

Enzyme Flexibility in Drosophila melanogaster  

Microsoft Academic Search

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

John Gibson

1970-01-01

273

Acrylate polymer immobilisation of enzymes  

Microsoft Academic Search

A rotating disk electrode analysis of pin-holes in polymer membrane coverings is described and the results correlated with\\u000a the performance of the polymers when used as immobilisation matrices for enzymes in amperometric biosensors. The polymer family\\u000a chosen for study is that of the acrylates and two preparations are considered via bulk polymerisation and emulsion polymerisation.\\u000a In the latter case PVA

E. A. H. Hall; J. Justin Gooding; Carl E. Hall; Nicolas Martens

1999-01-01

274

Earthworm Interactions with Soil Enzymes  

Microsoft Academic Search

\\u000a As one of the dominant members of soil fauna, earthworms fulfill significant tasks in the soil ecosystem by participating\\u000a in the physico-chemical processes of the soil, such as organic matter cycles, nutrient transformations, and modifications\\u000a in soil structure. These processes are also directed by the activities and amounts of the enzymes produced by soil microorganisms\\u000a that inhabit a wide range

Ridvan Kizilkaya; Ayten Karaca; Oguz Can Turgay; Sema Camci Cetin

275

Enzyme des Kohlenhydratstoffwechsels in Nektarien  

Microsoft Academic Search

1.The activity of some important enzymes of carbohydrate metabolism was investigated in several fractions of homogenized tissues of nectaries from Deutzia scabra and Convolvulus sepium in the secretion-phase. Considerable activity was found for the particle-associated hexokinase and the soluble fructokinase, phosphohexoseisomerase, sucrase, UTP-glucose-1-phosphate-uridyltransferase, acid and alkaline phosphatases, and pyrophosphatase. The activity of phosphoglucomutase was smaller, and that of starch-hydrolases and-phosphorylases

Maria Alejandra Rongine Fekete; Hubert Ziegler; Renate Wolf

1967-01-01

276

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

277

Substrate mediated enzyme prodrug therapy.  

PubMed

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

278

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

279

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

280

77 FR 16066 - Privacy Act of 1974; System of Records  

Federal Register 2010, 2011, 2012, 2013

...modify the system of records entitled, ``Freedom of Information Act, Privacy Act, and...June 4, 2001), and rename it ``Freedom of Information Act, Privacy Act, and...individuals who submit requests under the Freedom of Information Act (FOIA);...

2012-03-19

281

76 FR 4378 - Sunshine Act Meetings; Notice  

Federal Register 2010, 2011, 2012, 2013

...Consider and act on Resolution 2011-XXX thanking Victor M. Fortuno for his service...Consider and act on Resolution 2011-XXX dissolving the 2010 Search Committee for...Consider and act on Resolution 2011-XXX Commemorating the 100 Year Anniversary...

2011-01-25

282

Dialog Act Tagging Using Graphical Models  

Microsoft Academic Search

Detecting discourse patterns such as dialog acts (DAs) is an important factor for processing spoken conversations and meetings. Different techniques have been used to tag dialog acts in the past such as hidden Markov models and neural networks. In this work, a full analysis of dialog act tagging using different generative and conditional dynamic Bayesian networks (DBNs) is performed, where

Gang Ji; Jeff Bilmes

2005-01-01

283

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

284

Immobilized Enzymes and the Food Processing Industry.  

National Technical Information Service (NTIS)

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

P. F. Greenfield R. L. Lawrence

1974-01-01

285

Immobilization of Enzymes onto Insoluble Supports.  

National Technical Information Service (NTIS)

The immobilization of glucose oxidase and yeast-lactic dehydrogenase onto solid supports is studied and the deactivation of the enzyme catalysts in buffer solution is determined. Glucose oxidase was chemically coupled to both porous glass and a new enzyme...

W. M. Herring

1972-01-01

286

Enzyme-Enhanced Electrochemical Immunoassay for Phenytoin,  

National Technical Information Service (NTIS)

An important application of enzyme-mediated electrocatalysis is in immunoassays where the current amplification of the enzyme reaction enhances the sensitivity of the measurement. The immunological utility of the ferrocene/glucose oxidase (Fer/GOx) system...

M. Umana J. Walker M. Wani C. Whisnant E. Cook

1988-01-01

287

Silica-Immobilized Enzyme Reactors (Postprint).  

National Technical Information Service (NTIS)

Recent studies have demonstrated the applicability and versatility of immobilized enzyme reactors (IMERs) for chemical and biochemical synthesis and analysis. The majority of IMER systems rely on enzymes immobilized to packed matrices within flow-through ...

H. R. Luckarift

2007-01-01

288

A DNA tweezer-actuated enzyme nanoreactor.  

PubMed

The functions of regulatory enzymes are essential to modulating cellular pathways. Here we report a tweezer-like DNA nanodevice to actuate the activity of an enzyme/cofactor pair. A dehydrogenase and NAD(+) cofactor are attached to different arms of the DNA tweezer structure and actuation of enzymatic function is achieved by switching the tweezers between open and closed states. The enzyme/cofactor pair is spatially separated in the open state with inhibited enzyme function, whereas in the closed state, enzyme is activated by the close proximity of the two molecules. The conformational state of the DNA tweezer is controlled by the addition of specific oligonucleotides that serve as the thermodynamic driver (fuel) to trigger the change. Using this approach, several cycles of externally controlled enzyme inhibition and activation are successfully demonstrated. This principle of responsive enzyme nanodevices may be used to regulate other types of enzymes and to introduce feedback or feed-forward control loops. PMID:23820332

Liu, Minghui; Fu, Jinglin; Hejesen, Christian; Yang, Yuhe; Woodbury, Neal W; Gothelf, Kurt; Liu, Yan; Yan, Hao

2013-01-01

289

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

290

Extracellular functions of glycolytic enzymes of parasites: unpredicted use of ancient proteins.  

PubMed

In addition of their usual intracellular localization where they are involved in catalyzing reactions of carbohydrate and energy metabolism by glycolysis, multiple studies have shown that glycolytic enzymes of many organisms, but notably pathogens, can also be present extracellularly. In the case of parasitic protists and helminths, they can be found either secreted or attached to the surface of the parasites. At these extracellular localizations, these enzymes have been shown to perform additional, very different so-called "moonlighting" functions, such as acting as ligands for a variety of components of the host. Due to this recognition, different extracellular glycolytic enzymes participate in various important parasite-host interactions such as adherence and invasion of parasites, modulation of the host's immune and haemostatic systems, promotion of angiogenesis, and acquisition of specific nutrients by the parasites. Accordingly, extracellular glycolytic enzymes are important for the invasion of the parasites and their establishment in the host, and in determining their virulence. PMID:24602601

Gómez-Arreaza, Amaranta; Acosta, Hector; Quiñones, Wilfredo; Concepción, Juan Luis; Michels, Paul A M; Avilán, Luisana

2014-02-01

291

Enzymes toughen up for chemical processing  

SciTech Connect

While enzymes have been making tremendous inroads into detergent formulation and food processing, the penetration of these protein-based catalysts into other chemical-process manufacture and hazardous waste treatment--where they are slated to replace heavy metal catalysts and other processing aids--has been relatively slow. Recently, however, enhancements in the enzyme`s properties are opening the door wider for such broadened usage. Some of these non-traditional uses of enzymes are described.

Hairston, D.

1995-05-01

292

Chemistry and Flatulence: An Introductory Enzyme Experiment  

NASA Astrophysics Data System (ADS)

An inexpensive introductory-level enzyme experiment was developed using raffinose family sugars extracted from green split peas as a substrate and the enzymes alpha-galactosidase and sucrase found in Beano. The reaction studied was the hydrolysis of raffinose family sugars to galactose, glucose, and fructose, and the reaction rate was determined using a retail glucometer to measure the concentration of glucose. Results are given on the effect of substrate concentration, enzyme concentration, temperature, and heavy metals on enzyme activity.

Hardee, John R.; Montgomery, Tina M.; Jones, Wray H.

2000-04-01

293

Endangered Species Act and Western Water Rights  

SciTech Connect

The problems associated with the federal government enforcing the Endangered Species Act while the western states attempt to manage their water resources present a classic example of the conflict between federal environmental policy and state resource management programs. The author considers the effect of the federal government's ''regulatory property rights'' under the Endangered Species Act and section 404 of the Clean Water Act on water management by the western states. The author then proposes some ways in which to mitigate the conflict between the western states' objectives in managing their water resources and the federal government's objectives in enforcing the Endangered Species Act and section 404 of the Clean Water Act.

Tarlock, A.D.

1985-01-01

294

The Bayh-Dole Act turns 30.  

PubMed

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

Loise, Vicki; Stevens, Ashley J

2010-10-01

295

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

296

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

297

Complex Pectins: Structure elucidation using enzymes  

Microsoft Academic Search

A pectic fraction, retained by ultrafiltration of the juice from enzyme treated apple tissue and resistant to further enzymic degradation, was isolated and characterized using chemical and enzymic methods. The fraction was termed MHR (modified hairy regions) and this fraction was characterized by a high arabinose content, next to a high rhamnose to galacturonic acid ratio and a high acetyl

H. A. Schols; A. G. J. Voragen

1996-01-01

298

Stabilization of enzyme immunoassays for atrazine  

Microsoft Academic Search

Reagent stability is an important issue in immunoassay technology. Enzyme immunoassays (EIA) for atrazine are used as an example for investigating the influence of different stabilizing agents on the activity of polyclonal and monoclonal antibodies (Ab), enzyme tracer (ET) as well as enzyme substrate after storage at different temperatures. When lyophilized Ab were stored for two weeks at 30°C, ca.

Andrea Dankwardt; Jutta Müller; Bertold Hock

1998-01-01

299

Hydrolytic enzyme activity in landfilled refuse  

Microsoft Academic Search

Extracellular hydrolytic enzyme activity was assayed in 28 refuse samples excavated from 14 bore holes in Fresh Kills Landfill, Staten Island, N. Y. Esterases, proteases and amylases were present in all of the samples. Enzyme screening assays utilizing the API-ZYM test system showed the incidence of enzymes in the order: specific phosphatases > esterases > glycosyl hydrolases. Measurement of cellulase

A. C. Palmisano; B. S. Schwab; D. A. Maruscik

1993-01-01

300

Engineered enzymes for improved organic synthesis  

Microsoft Academic Search

Recent developments to modify enzymes for use in organic synthesis have targeted several areas. These include altering the reaction mechanism of the enzyme to catalyse new reactions, switching substrate specificity, expanding substrate specificity, and improving substrate specificity, such as enantioselectivity in kinetic resolutions. Such modifications can be achieved either by rational redesign, which requires knowledge of the enzyme structure, or

Karl Hult; Per Berglund

2003-01-01

301

Technologies of Immobilized Enzymes and Their Applications  

Microsoft Academic Search

The synthesis of novel carrier material for immobilization enzyme is one of the most important research fields for the future development of the enzyme immobilization. The intelligent material and the natural carrier materials also play important roles in enzyme immobilization. Based on the usage of new scientific technology, such as oriented immobilization, immobilization by using ultrasonic and radiation, highly active

Bai Yongxiao; Li Yanfeng; Ma Yingxia; Zhou Lincheng; Ma Pengcheng

302

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

Microsoft Academic Search

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

Eir??kur Stephensen; Joachim Sturve; Lars Förlin

2002-01-01

303

76 FR 18365 - Fair Credit Reporting Act and Bank Secrecy Act Compliance  

Federal Register 2010, 2011, 2012, 2013

...Credit Reporting Act and Bank Secrecy Act Compliance AGENCY: National Credit Union Administration...amending its Bank Secrecy Act (BSA) Compliance and Fair Credit Reporting Act (FCRA...Appendix J to 12 CFR part 717, and BSA Compliance (12 CFR part 748) regulations to...

2011-04-04

304

Potent enzyme inhibitors derived from dromedary heavy-chain antibodies.  

PubMed Central

Evidence is provided that dromedary heavy-chain antibodies, in vivo-matured in the absence of light chains, are a unique source of inhibitory antibodies. After immunization of a dromedary with bovine erythrocyte carbonic anhydrase and porcine pancreatic alpha-amylase, it was demonstrated that a considerable amount of heavy-chain antibodies, acting as true competitive inhibitors, circulate in the bloodstream. In contrast, the conventional antibodies apparently do not interact with the enzyme's active site. Next we illustrated that peripheral blood lymphocytes are suitable for one-step cloning of the variable domain fragments in a phage-display vector. By bio-panning, several antigen-specific single-domain fragments are readily isolated for both enzymes. In addition we show that among those isolated fragments active site binders are well represented. When produced as recombinant protein in Escherichia coli, these active site binders appear to be potent enzyme inhibitors when tested in chromogenic assays. The low complexity of the antigen-binding site of these single-domain antibodies composed of only three loops could be valuable for designing smaller synthetic inhibitors.

Lauwereys, M; Arbabi Ghahroudi, M; Desmyter, A; Kinne, J; Holzer, W; De Genst, E; Wyns, L; Muyldermans, S

1998-01-01

305

Glucocorticoid metabolism and reproduction: a tale of two enzymes.  

PubMed

Within potential target cells, the actions of physiological glucocorticoids (cortisol and corticosterone) are modulated by isoforms of the enzyme 11 beta-hydroxysteroid dehydrogenase (11 beta HSD). To date, two isoforms of 11 beta HSD have been cloned: 11 beta HSD1 acts predominantly as an NADP(H)-dependent reductase to generate active cortisol or corticosterone, and 11 beta HSD2 is a high affinity NAD(+)-dependent enzyme that catalyses the enzymatic inactivation of glucocorticoids. Whereas the regeneration of active glucocorticoids by 11 beta HSD1 has been implicated in the cellular mechanisms of pituitary function, ovulation and parturition, the enzymatic inactivation of cortisol and corticosterone by 11 beta HSD enzymes appears to be central to the protection of gonadal steroidogenesis, prevention of intra-uterine growth retardation, and lactation. Recent evidence indicates that follicular fluid contains endogenous modulators of cortisol metabolism by 11 beta HSD1, the concentrations of which are associated with the clinical outcome of assisted conception cycles and are altered in cystic ovarian disease. In conclusion, the two cloned isoforms of 11 beta HSD fulfil diverse roles in a wide range of reproductive processes from conception to lactation. PMID:14525525

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

2003-10-01

306

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

307

Peptidoglycan Remodeling by the Coordinated Action of Multispecific Enzymes  

PubMed Central

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.

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

2014-01-01

308

[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

309

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

310

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

311

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.

312

Finding Sequences for over 270 Orphan Enzymes.  

PubMed

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

313

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.

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

2014-01-01

314

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

Code of Federal Regulations, 2010 CFR

...Agriculture 3 2010-01-01 2010-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436...Quality Specifications for Raw Material § 58.436 Rennet, pepsin, other milk clotting enzymes and flavor enzymes....

2010-01-01

315

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

Code of Federal Regulations, 2010 CFR

...Agriculture 3 2009-01-01 2009-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436...Quality Specifications for Raw Material § 58.436 Rennet, pepsin, other milk clotting enzymes and flavor enzymes....

2009-01-01

316

Enzyme/indicator optrodes for detection of heavy metal ions and pesticides  

NASA Astrophysics Data System (ADS)

Composite films containing enzyme and indicator molecules were produced by means of polyelectrolyte self-assembly. These membranes provide two functions: (i) molecular recognition of the substratum by respective enzyme, and (ii) optrode transducing, when the products o the substratum decomposition affect optical spectra of indicator molecules. Apart from direct registration of enzyme reactions, inhibition reactions can also be monitored with this method. Particularly, heavy metal salts and phosphor organic pesticides acting as inhibitors for Urease and Cholinesterase, respectively, were registered. Composite PESA films were deposited onto glass slides and consisted of several layers of poly(alylamine) hydrochloride (PAA) alternated with indicator molecules, either Cyclo-tetra- chromotropylene or Thymol Blue, both containing SO3- Na+ groups. Then a few layers of PAA/enzyme were deposited on top. A typical structure of the samples was (PAA/Indicator)n/(PAA/Enzyme)m/PAA with n equals 1-5. The obtained films were characterized with UV-visible absorption spectroscopy. The effect of the substrate decomposition on the UV-vis spectra of respective indicator molecules was studied. The inhibition of enzymes Urease and Cholinesterase by heavy metal ions and phosphor organic pesticide, respectively was found. The results obtained show the prospects towards development of optical enzyme sensor arrays.

Nabok, Alexei V.; Ray, Asim K.; Starodub, Nickolaj F.; Dowker, Kenneth P.

2000-12-01

317

Lactosylamidine-based affinity purification for cellulolytic enzymes EG I and CBH I from Hypocrea jecorina and their properties  

Microsoft Academic Search

Selective adsorption and separation of ?-glucosidase, endo-acting endo-?-(1?4)-glucanase I (EG I), and exo-acting cellobiohydrolase I (CBH I) were achieved by affinity chromatography with ?-lactosylamidine as ligand. A crude cellulase preparation from Hypocrea jecorina served as the source of enzyme. When crude cellulase was applied to the lactosylamidine-based affinity column, ?-glucosidase appeared in the unbound fraction. By contrast, EG I and

Makoto Ogata; Yumiko Kameshima; Takeshi Hattori; Kousuke Michishita; Tomohiro Suzuki; Hirokazu Kawagishi; Kazuhide Totani; Jun Hiratake; Taichi Usui

318

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

319

Enzyme diversity in halophilic archaea.  

PubMed

The halophilic archaea display a considerable extent of enzyme diversity. The presence or absence of certain enzymatic activities is closely linked with the taxonomic status of the strains investigated. Thus, Halobacterium species such as Hb. salinarium, Hb. halobium, and Hb. cutirubrum differ from most other Halobacteriaceae tested by the possession of an NAD(+)-dependent glycerol dehydrogenase, by the absence of methylglyoxal synthase activity, and the ability of fermentative growth on arginine. Species such as Hb. saccharovorum and Hb. sodomense, which are still classified within the genus Halobacterium, have an enzymatic machinery greatly different from that of the Hb. salinarium-Hb. halobium group, confirming the need for a taxonomic reappraisal of these species. The presence of NAD(+)-dependent D-lactate dehydrogenase is characteristic of representatives of the genus Haloarcula, which possess only low activities of NAD(+)-independent L- and D-lactate dehydrogenases, if at all. Other enzymes which show considerable diversity are fructose 1,6-bisphosphate aldolase, of which two classes exist, and ribulose 1,6-bisphosphate carboxylase, which is present in a limited number of species. PMID:7873098

Oren, A

1994-09-01

320

Is acting on delusions autonomous?  

PubMed Central

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

2013-01-01

321

Summary of the First ACTS Propagation Workshop  

NASA Technical Reports Server (NTRS)

The first Advanced Communications Technology Satellite (ACTS) Propagation Studies Workshop (APSW I), organized by NASA/Jet Propulsion Laboratory (JPL) to plan propagation experiments and studies with NASA's ACTS, convened in Santa Monica, California, during November 28 and 29, 1989. The objectives of APSW I were to identify general and ACTS-related propagation needs, and to prepare recommendations for a study plan incorporating scientific and systems requirements related to deployment of 8 to 10 propagation terminals in the USA in support of ACTS experimental activities. A summary of workshop activities is given.

Rogers, David V.

1990-01-01

322

CORRIE: enzyme sequence annotation with confidence estimates.  

PubMed

Using a previously developed automated method for enzyme annotation, we report the re-annotation of the ENZYME database and the analysis of local error rates per class. In control experiments, we demonstrate that the method is able to correctly re-annotate 91% of all Enzyme Classification (EC) classes with high coverage (755 out of 827). Only 44 enzyme classes are found to contain false positives, while the remaining 28 enzyme classes are not represented. We also show cases where the re-annotation procedure results in partial overlaps for those few enzyme classes where a certain inconsistency might appear between homologous proteins, mostly due to function specificity. Our results allow the interactive exploration of the EC hierarchy for known enzyme families as well as putative enzyme sequences that may need to be classified within the EC hierarchy. These aspects of our framework have been incorporated into a web-server, called CORRIE, which stands for Correspondence Indicator Estimation and allows the interactive prediction of a functional class for putative enzymes from sequence alone, supported by probabilistic measures in the context of the pre-calculated Correspondence Indicators of known enzymes with the functional classes of the EC hierarchy. The CORRIE server is available at: http://www.genomes.org/services/corrie/. PMID:17570146

Audit, Benjamin; Levy, Emmanuel D; Gilks, Wally R; Goldovsky, Leon; Ouzounis, Christos A

2007-01-01

323

Enzyme-polymer based environmental monitors  

NASA Astrophysics Data System (ADS)

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

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

2010-04-01

324

Ethanologenic Enzymes of Zymomonas mobilis  

SciTech Connect

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

Ingram, Lonnie O'Neal

1999-03-01

325

Enzyme analysis of Schistosoma haematobium*  

PubMed Central

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

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

1983-01-01

326

Sfericase, a novel proteolytic enzyme.  

PubMed

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

Yoshida, K

1983-09-01

327

Phase II enzyme induction by a carotenoid, lutein, in a PC12D neuronal cell line.  

PubMed

The mechanism by which lutein, a carotenoid, acts as an antioxidant in retinal cells is still not fully understood. Here, lutein treatment of a neuronal cell line (PC12D) immediately resulted in reduced intracellular ROS levels, implying that it has a direct role in ROS scavenging. Significantly, lutein treatment also induced phase II antioxidative enzyme expression, probably via a nuclear factor-like 2 (Nrf2) independent pathway. This latter mechanism could explain why lutein acts diversely to protect against oxidative/cytotoxic stress, and why it is physiologically involved in the human neural tissue, such as the retina. PMID:24613837

Miyake, Seiji; Kobayashi, Saori; Tsubota, Kazuo; Ozawa, Yoko

2014-04-01

328

Short-acting versus Long-acting Medications for the Treatment of ADHD  

PubMed Central

Primary care physicians, pediatricians, and psychiatrists account for approximately 80 percent of attention deficit hyperactivity disorder (ADHD) treatments prescribed in the United States. Selection of short-acting versus long-acting ADHD treatment varies by specialty with long-acting agents representing 56 percent of primary care prescriptions, 64 percent of psychiatrist prescriptions, and 79 percent of pediatric prescriptions. There appears to be a correlation between short-acting versus long-acting treatment selection and age, with long-acting agents accounting for 78 percent of prescriptions for pediatric patients (age 0–17) but only 49 percent of prescriptions for adults (patients aged 18+). A discussion of data is included.

Cascade, Elisa; Kalali, Amir H.; Weisler, Richard H.

2008-01-01

329

Na-taurodeoxycholate acts as a specific intestinal stimulus of exocrine pancreatic secretion in man.  

PubMed

The effect of intraduodenally administered cattle bile, Na-taurodeoxycholate, and Na-taurocholate on secretin-stimulated exocrine pancreatic secretion was investigated on 40 fasting young healthy volunteers. Intraduodenal bile stimulated significantly and dose-dependently hydrokinetic and ecbolic pancreatic secretion. Only bile, but not secretin intravenously, both applied in a dosage equivalent with respect to their hydrokinetic action, caused a significant increase of enzyme output and enzyme concentration as well. Intraduodenal Na-taurodeoxycholate enhanced also dose-dependently secretin-stimulated volume, bicarbonate, and enzyme secretion. The effect was related to the load, not to the concentration of this bile salt. On the other side, Na-taurocholate had only a weak and not dose-dependent hydrokinetic and no ecbolic effect. It is concluded that not bile salts in general, but only certain of them--like Na-taurodeoxycholate--are the effective constituents of bile, acting as specific intraduodenal stimulants of hydrokinetic and ecbolic pancreatic secretion. PMID:2448866

Lehnert, P; Hempen, I; Fiedler, F; Hotz, E; Danzl, C; Mitra, H; Riepl, R

1987-01-01

330

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.

Green, Brett J.; Beezhold, Donald H.

2011-01-01

331

Affordable Care Act's Role in Preventing and Ending Homelessness  

MedlinePLUS

... Affordable Care Act’s Role in Preventing and Ending Homelessness Download associated files The Affordable Care Act's Role in Preventing and Ending Homelessness What is the Affordable Care Act? On March ...

332

Ultrafast-Acting Insulins: State of the Art  

PubMed Central

Optimal coverage of prandial insulin requirements remains an elusive goal. The invention of rapid-acting insulin analogs (RAIAs) was a big step forward in reducing postprandial glycemic excursions in patients with diabetes in comparison with using regular human insulin; however, even with these, the physiological situation cannot be adequately mimicked. Developing ultrafast-acting insulins (UFIs)—showing an even more rapid onset of action and a shorter duration of action after subcutaneous (SC) administration—is another step forward in achieving this goal. The need for UFIs has been gradually recognized over the years, and subsequently, a number of different approaches to cover this need are in clinical development. A rapid increase in circulating insulin levels can be achieved by different measures: modification of the primary structure of insulin molecule (as we know from RAIAs), addition of excipients that enhance the appearance in the monomeric state post-injection, or addition of enzymes that enable more free spreading of the insulin molecules in the SC tissue. Other measures to increase the insulin absorption rate increase the local blood flow nearby the insulin depot in the SC tissue, injecting the insulin intradermally or applying via another route, e.g., the lung. The development of these approaches is in different stages, from quite early stages to nearing market authorization. In time, daily practice will show if the introduction of UFIs will fulfill their clinical promise. In this review, the basic idea for UFIs will be presented and the different approaches will be briefly characterized.

Heinemann, Lutz; Muchmore, Douglas B.

2012-01-01

333

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

334

Enzymes toughen up for chemical processing  

Microsoft Academic Search

While enzymes have been making tremendous inroads into detergent formulation and food processing, the penetration of these protein-based catalysts into other chemical-process manufacture and hazardous waste treatment--where they are slated to replace heavy metal catalysts and other processing aids--has been relatively slow. Recently, however, enhancements in the enzyme`s properties are opening the door wider for such broadened usage. Some of

1995-01-01

335

Turning enzymes ON with small molecules  

Microsoft Academic Search

Drug discovery and chemical genetic efforts typically focus on the identification and design of inhibitors or loss-of-function probes as a means to perturb enzyme function. These tools are effective in determining the physiological consequence of ablating the activity of a specific enzyme. Remarkably, nearly a dozen examples of non-natural small molecules that activate enzyme catalysis have been identified within the

Julie A Zorn; James A Wells

2010-01-01

336

The molybdenum oxotransferases and related enzymes.  

PubMed

A perspective is provided of recent advances in our understanding of molybdenum-containing enzymes other than nitrogenase, a large and diverse group of enzymes that usually (but not always) catalyze oxygen atom transfer to or from a substrate, utilizing a Mo=O group as donor or acceptor. An emphasis is placed on the diversity of protein structure and reaction catalyzed by each of the three major families of these enzymes. PMID:23318732

Hille, Russ

2013-03-01

337

Microbial enzymes for aromatic compound hydroxylation  

Microsoft Academic Search

Redox enzymes are ubiquitous in all living organisms. In fact, oxidation and reduction reactions are fundamental for the transformation\\u000a of cellular and external compounds both for cell reproduction and for energy production. Redox enzymes share a common characteristic\\u000a that is the capacity of transferring electrons to and from molecules. In addition, microorganisms contain many oxidative enzymes,\\u000a and because they are

Patrizia Di Gennaro; Anna Bargna; Guido Sello

2011-01-01

338

The complete enzymic hydrolysis of crosslinked proteins.  

PubMed

Procedures used for the complete enzymic hydrolysis of proteins are reviewed. The successful application of complete enzymic hydrolysis in the detection of naturally occurring isopeptide crosslinks and various other types of chemically introduced crosslinks is described. The method may fail if the level of crosslinking is too high, or if crosslinking is accompanied by racemization. Although it is usual to cleave disulphide crosslinks prior to enzymic digestion, the necessity for this in all cases is questioned. PMID:906920

Milligan, B; Holt, L A

1977-01-01

339

Analytical applications of reactors containing immobilized enzymes  

Microsoft Academic Search

The theory for analytical packed-enzyme reactors is discussed and it is shown that a 100% conversion efficiency gives many\\u000a advantages. This concept has been applied to methods for substrate determinations of urea, amino acids, and glucose. Enzyme\\u000a reactors have also been used in the effluent from a Chromatographic column to enhance selectivity and sensitivity for cholesterol.\\u000a Enzyme reactors for the

Gillis Johansson

1982-01-01

340

Use of immobilized enzymes in chemical analysis  

Microsoft Academic Search

Immobilized enzymes are becoming increasingly popular as analytical reagents because of their reusability, stability, and\\u000a sensitivity to many inhibitors that would seriously interfere in assays using soluble enzymes. In this article, some of the\\u000a kinetic and catalytic effects of immobilized enzymes in analysis will be discussed. The shift of the activity-pH profile curves\\u000a on immobilization, the changes in temperature dependence,

George G. Guilbault

1977-01-01

341

A new group of exo-acting family 28 glycoside hydrolases of Aspergillus niger that are involved in pectin degradation.  

PubMed

The fungus Aspergillus niger is an industrial producer of pectin-degrading enzymes. The recent solving of the genomic sequence of A. niger allowed an inventory of the entire genome of the fungus for potential carbohydrate-degrading enzymes. By applying bioinformatics tools, 12 new genes, putatively encoding family 28 glycoside hydrolases, were identified. Seven of the newly discovered genes form a new gene group, which we show to encode exoacting pectinolytic glycoside hydrolases. This group includes four exo-polygalacturonan hydrolases (PGAX, PGXA, PGXB and PGXC) and three putative exo-rhamnogalacturonan hydrolases (RGXA, RGXB and RGXC). Biochemical identification using polygalacturonic acid and xylogalacturonan as substrates demonstrated that indeed PGXB and PGXC act as exo-polygalacturonases, whereas PGXA acts as an exo-xylogalacturonan hydrolase. The expression levels of all 21 genes were assessed by microarray analysis. The results from the present study demonstrate that exo-acting glycoside hydrolases play a prominent role in pectin degradation. PMID:16822232

Martens-Uzunova, Elena S; Zandleven, Joris S; Benen, Jaques A E; Awad, Hanem; Kools, Harrie J; Beldman, Gerrit; Voragen, Alphons G J; Van den Berg, Johan A; Schaap, Peter J

2006-11-15

342

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

343

The Equal Access Act: Recent Court Decisions.  

ERIC Educational Resources Information Center

Examines court decisions which led to the passage of the Equal Access Act of 1984. Although the act was designed to clarify the issue over the legality of permitting religious clubs to meet on school property, it may have created more confusion. Concludes that the Supreme Court may have to decide the issue. (SLM)

Bjorklun, Eugene C.

1989-01-01

344

The Compensation Act 2006 and School Trips  

ERIC Educational Resources Information Center

The Compensation Act 2006 received its Royal Assent on 25 July 2006. The Act allows the courts to have regard to the social utility of "desirable activities", including school trips, in considering negligence claims. The article reviews the law of negligence as it affects teachers of the very young and considers the possible impact of the…

Hunter-Jones, John

2006-01-01

345

Faces of the Recovery Act: Sun Catalytix  

SciTech Connect

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

2010-01-01

346

Endangered Species Act: Consideration of Economic Factors.  

National Technical Information Service (NTIS)

The Endangered Species Act (ESA) provides for the listing and protection of species that are found to be endangered or threatened - species that might become extinct. The listing of a species as endangered triggers the prohibitions in the Act against 'tak...

P. Baldwin

2003-01-01

347

Endangered Species Act and Western Water Rights  

Microsoft Academic Search

The problems associated with the federal government enforcing the Endangered Species Act while the western states attempt to manage their water resources present a classic example of the conflict between federal environmental policy and state resource management programs. The author considers the effect of the federal government's ''regulatory property rights'' under the Endangered Species Act and section 404 of the

Tarlock

1985-01-01

348

The USA PATRIOT Act: Archival Implications  

ERIC Educational Resources Information Center

In October 2001, Congress passed the USA PATRIOT Act to strengthen the ability of the U.S. government to combat terrorism. Unfortunately, some sections of the Act strike at core values and practices of libraries and archives, especially in the areas of record keeping, privacy, confidentiality, security, and access to the collections. This article…

Trinkaus-Randall, Gregor

2005-01-01

349

Nursing Training Act of 1975. Fact Sheets.  

ERIC Educational Resources Information Center

The Nursing training Act of 1975 revises and extends the nursing training authorities provided under Title VIII of the Public Health Service Act for a three-year period, thus providing aid to nursing training through September 30, 1978. It provides two new, separate authorities for the support of Advanced Nursing Training and Nursing Practitioner…

Health Resources Administration (DHEW/PHS), Bethesda, MD. Div. of Nursing.

350

ACT UP as a Structure of Feeling  

ERIC Educational Resources Information Center

Revisiting AIDS Coalition to Unleash Power (ACT UP) restarts the "panic of loss" characterizing the author's youth. The author argues that the 25th anniversary of ACT UP marks the failure to consider Raymond Williams's "structure of feeling". Williams counterposes this structure against falsely viewing the past as formalized into something…

Gingrich-Philbrook, Craig

2012-01-01

351

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.

352

78 FR 28895 - Sunshine Act Meetings  

Federal Register 2010, 2011, 2012, 2013

...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

353

77 FR 52066 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013

...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

354

Second Language Learners and Speech Act Comprehension  

ERIC Educational Resources Information Center

Recognizing the specific speech act ( Searle, 1969) that a speaker performs with an utterance is a fundamental feature of pragmatic competence. Past research has demonstrated that native speakers of English automatically recognize speech acts when they comprehend utterances (Holtgraves & Ashley, 2001). The present research examined whether this…

Holtgraves, Thomas

2007-01-01

355

Medicare and the Affordable Care Act  

Microsoft Academic Search

The recently enacted Patient Protection and Affordable Care Act made modest changes to improve Medicare and obtained a substantial share of funding for the Act's broader reforms from future spending reductions in the program. Drug benefits and preventive services were improved. While painful, the spending reductions will have only moderate impacts on beneficiaries and should help achieve the goals of

Marilyn Moon

2012-01-01

356

Consumer protection act for digital products  

Microsoft Academic Search

This report proposes a `Consumer Protection Act for Digital Products' to support electronic commerce and to control the increasing abuse and lack of security on the national information highways. Patterned after the `Food and Drug Act of 1906 (21 USC)' and subsequent legislation, a new agency similar to that of the FDA would have the authority `to develop administrative policy

Viktor E. Hampel

1996-01-01

357

Orphan Drug Act: Implementation and Impact.  

National Technical Information Service (NTIS)

The purpose of this inspection was to assess the implementation of the Orphan Drug Act of 1983 and its impact on industry and patients. Congress passed the Orphan Drug Act of 1983 to stimulate the development of drugs for rare diseases. A rare disease is ...

2001-01-01

358

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

359

Ability and Expertise in Act Generation.  

National Technical Information Service (NTIS)

Act generation is a process used by decision makers to create a set of possible actions that might solve a problem. Since previous research has shown college students to generate incomplete sets of possible actions in act generation, the sets of actions g...

P. D. Engelmann C. F. Gettys

1983-01-01

360

75 FR 67396 - Sunshine Act Meeting Notice  

Federal Register 2010, 2011, 2012, 2013

...well as a proposal regarding a research project. The Board will also receive briefings...1622.5(f) protects from disclosure investigatory records that might interfere with enforcement...act on proposal regarding a research project. 6. Consider and act on a...

2010-11-02

361

The Clean Water Act of 1977  

Microsoft Academic Search

The author examines major features of the 1977 Clean Water Act Amendments, which are aimed at limiting water pollution at industrial and municipal discharge points without changing the basic goals of the Act. Title I amendments, for example, strengthen the role of states and add financing assistance for wastewater control. Other amendments deal with improving both implementation and compliance procedures

RIDGWAY M. HALL JR.; R. M. Jr

1978-01-01

362

African Growth and Opportunity Act Competitiveness Report.  

National Technical Information Service (NTIS)

In 2005, 37 sub-Saharan African countries are eligible for benefits under the African Growth and Opportunity Act (AGOA). Section 9 of the AGOA Acceleration Act of 2004 states that the Administration shall conduct a study on each AGOA-eligible country that...

2005-01-01

363

The ACTS propagation terminal delivery and support  

NASA Technical Reports Server (NTRS)

Viewgraphs on the Advanced Communications Technology Satellite (ACTS) propagation terminal delivery and support are included. Topics covered include: the ACTS propagation terminal (APT) development program; terminal overview; physical units; test results; status of terminals and schedule; shipping cartons; and site support.

Stutzman, Warren L.

1993-01-01

364

Signs of Life: Acting and Representation.  

ERIC Educational Resources Information Center

Examines some of the different representational practices of acting in the context of a theory of signs. Focuses on the intrinsic characteristics of signs and the representational practices of acting. Discusses the contributions of Stanislavsky and Brecht to this area. (JMF)

Stevens, Tony

1980-01-01

365

A Voting Rights Act Handbook for Chicanos.  

ERIC Educational Resources Information Center

In the summer of 1975, the protective provisions of the 1965 Voting Rights Act were extended to parts of the Southwest. This marks a significant point in the history to secure for Chicanos a meaningful participation in the political process. The basic purpose of the Act assures that minorities can participate in the election process without any…

Mexican American Legal Defense and Educational Fund, Inc., San Francisco, CA.

366

The Voting Rights Act: Unfulfilled Goals.  

ERIC Educational Resources Information Center

This report examines the current status of minority voting rights covered by the special provisions of the Voting Rights Act of 1965. The special provisions prescribe added protection of minority voting rights in those jurisdictions where discrimination in voting has been most pervasive. The report explains the Voting Rights Act and discusses its…

Commission on Civil Rights, Washington, DC.

367

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.

368

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

369

Mechanisms and inhibition of uracil methylating enzymes  

PubMed Central

Uracil methylation is essential for survival of organisms and passage of information from generation to generation with high fidelity. Two alternative uridyl methylation enzymes, flavin-dependent thymidylate synthase and folate/FAD-dependent RNA methyltransferase, have joined the long-known classical enzymes, thymidylate synthase and SAM-dependent RNA methyltransferase. These alternative enzymes differ significantly from their classical counterparts in structure, cofactor requirements and chemical mechanism. This review covers the available structural and mechanistic knowledge of the classical and alternative enzymes in biological uracil methylation, and offers a possibility of using inhibitors specifically aiming at microbial thymidylate production as antimicrobial drugs.

Mishanina, Tatiana V.; Koehn, Eric M.; Kohen, Amnon

2011-01-01

370

Nanomaterials as matrices for enzyme immobilization.  

PubMed

Nanomaterials constitute novel and interesting matrices for enzyme immobilization. While their high surface to volume ratio is an obvious advantage, their Brownian motion can impact the behavior of enzymes immobilized on these matrices. Carbon nanotubes, superparamagnetic nanoparticles, and mesoporous materials constitute some important classes of matrices. Such immobilized enzyme systems have been used in both aqueous and low water media for biocatalysis and resolution of racemates. This overview examines the behavior of enzymes immobilized on nanomaterials and discusses the results reported with such biocatalyst preparations. PMID:20958099

Gupta, Munishwar N; Kaloti, Mandeep; Kapoor, Manali; Solanki, Kusum

2011-04-01

371

Nematicidal enzymes from microorganisms and their applications.  

PubMed

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

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

2013-08-01

372

77 FR 15555 - Freedom of Information Act and Privacy Act Procedures  

Federal Register 2010, 2011, 2012, 2013

...and Part 9301 RIN 3460-AA00 Freedom of Information Act and Privacy...Afghanistan Reconstruction under the Freedom of Information Act (FOIA...Accordingly, a regulatory impact analysis is not required...Administrative practice and procedure, Freedom of information,...

2012-03-16

373

77 FR 34179 - Freedom of Information Act and Privacy Act Procedures  

Federal Register 2010, 2011, 2012, 2013

...5 Part 9301 RIN 3460-AA00 Freedom of Information Act and Privacy...Afghanistan Reconstruction under the Freedom of Information Act (FOIA...Accordingly, a regulatory impact analysis is not required...Administrative practice and procedure, Freedom of information,...

2012-06-11

374

Enzyme-catalysed peptide amidation. Isolation of a stable intermediate formed by reaction of the amidating enzyme with an imino acid.  

PubMed

A series of hydrazones and semicarbazones of glyoxylic acid were shown to have a potent inhibitory effect on the enzyme-catalysed conversion of D-Tyr-Val-Gly to D-Tyr-Val-NH2. Among the derivatives tested, the inhibitory activity was increased by the presence of hydrophobic substituents and decreased by polar substituents. The inhibition produced by glyoxylic acid phenylhydrazone was shown to be competitive. No inhibition was obtained with pyruvic acid phenylhydrazone, which possesses a methyl group in place of the alpha-H of glyoxylic acid phenylhydrazone. The inhibitory potencies of these non-peptide substances are in accord with the specificity exhibited by the amidating enzyme in its reaction with peptide substrates. The inhibition produced by the glyoxylic acid derivatives was shown to be due to their ability to act as substrates for the peptide-amidating enzyme. The product formed from [14C]glyoxylic acid phenylhydrazone was identified as oxalic acid phenylhydrazide by co-chromatography in three chromatographic systems. The results demonstrate that the enzyme-catalysed oxidation of glyoxylic acid phenylhydrazone takes place by a mechanism involving hydroxylation. It is implicit that peptide amidation catalysed by the same enzyme proceeds by a similar mechanism. PMID:3691506

Bradbury, A F; Smyth, D G

1987-12-15

375

39 CFR 3004.30 - Relationship among the Freedom of Information Act, the Privacy Act, and the Commission's...  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Relationship among the Freedom of Information Act, the Privacy Act...COMMISSION PERSONNEL PUBLIC RECORDS AND FREEDOM OF INFORMATION ACT § 3004.30 Relationship among the Freedom of Information Act, the Privacy...

2013-07-01

376

19 CFR 147.23 - Compliance with Plant Quarantine Act and Federal Food, Drug, and Cosmetic Act.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Compliance with Plant Quarantine Act and Federal Food, Drug...Other Laws § 147.23 Compliance with Plant Quarantine Act and Federal Food, Drug, and Cosmetic Act. (a) Plant Quarantine Act. The entry of...

2013-04-01

377

Exploring primary care activities in ACT teams.  

PubMed

People with serious mental illness often receive inadequate primary and preventive care services. Federal healthcare reform endorses team-based care that provides high quality primary and preventive care to at risk populations. Assertive community treatment (ACT) teams offer a proven, standardized treatment approach effective in improving mental health outcomes for the seriously mentally ill. Much is known about the effectiveness of ACT teams in improving mental health outcomes, but the degree to which medical care needs are addressed is not established. The purpose of this study was to explore the extent to which ACT teams address the physical health of the population they serve. ACT team leaders were invited to complete an anonymous, web-based survey to explore attitudes and activities involving the primary care needs of their clients. Information was collected regarding the use of health screening tools, physical health assessments, provision of medical care and collaboration with primary care systems. Data was analyzed from 127 team leaders across the country, of which 55 completed the entire survey. Nearly every ACT team leader believed ACT teams have a role in identifying and managing the medical co-morbidities of their clientele. ACT teams report participation in many primary care activities. ACT teams are providing a substantial amount of primary and preventive services to their population. The survey suggests standardization of physical health identification, management or referral processes within ACT teams may result in improved quality of medical care. ACT teams are in a unique position to improve physical health care by virtue of having medically trained staff and frequent, close contact with their clients. PMID:24337472

Vanderlip, Erik R; Williams, Nancy A; Fiedorowicz, Jess G; Katon, Wayne

2014-05-01

378

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

379

Structure-based repurposing of FDA-approved drugs as inhibitors of NEDD8-activating enzyme.  

PubMed

We report the discovery of an inhibitor of NEDD8-activating enzyme (NAE) by an integrated virtual screening approach. Piperacillin 1 inhibited NAE activity in cell-free and cell-based systems with high selectivity. Furthermore, piperacillin 1 was able to inhibit the degradation of the NAE downstream protein substrate p27(kip1). Our molecular modeling and kinetic studies suggested that this compound may act as a non-covalent ATP-competitive inhibitor of NAE. PMID:24657219

Zhong, Hai-Jing; Liu, Li-Juan; Chan, Daniel Shiu-Hin; Wang, Hui-Min; Chan, Philip Wai Hong; Ma, Dik-Lung; Leung, Chung-Hang

2014-07-01

380

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

Microsoft Academic Search

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

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

1997-01-01

381

78 FR 25685 - Magnuson-Stevens Act Provisions; Implementation of the Shark Conservation Act of 2010  

Federal Register 2010, 2011, 2012, 2013

...Act Provisions; Implementation of the Shark Conservation Act of 2010 AGENCY: National...rule to implement the provisions of the Shark Conservation Act of 2010 (SCA) and prohibit...person from removing any of the fins of a shark at sea, possessing shark fins on...

2013-05-02

382

The Library Systems Act and Rules for Administering the Library Systems Act.  

ERIC Educational Resources Information Center

This document contains the Texas Library Systems Act and rules for administering the Library Systems Act. Specifically, it includes the following documents: Texas Library Systems Act; Summary of Codes;Texas Administrative Code: Service Complaints and Protest Procedure; Criteria For Texas Library System Membership; and Certification Requirements…

Texas State Library, Austin. Library Development Div.

383

75 FR 36535 - Freedom of Information Act, Privacy Act of 1974; Implementation  

Federal Register 2010, 2011, 2012, 2013

...Office of the Secretary 31 CFR Part 1 Freedom of Information Act, Privacy Act of 1974...on the disclosure of records under the Freedom of Information Act (FOIA) and its regulations...errors. List of Subjects in 31 CFR Part 1 Freedom of Information; Privacy. 0...

2010-06-28

384

Low-potential amperometric enzyme biosensor for xanthine and hypoxanthine.  

PubMed

The bacterial xanthine dehydrogenase (XDH) from Rhodobacter capsulatus was immobilized on an edge-plane pyrolytic graphite (EPG) electrode to construct a hypoxanthine/xanthine biosensor that functions at physiological pH. Phenazine methosulfate (PMS) was used as a mediator which acts as an artificial electron-transfer partner for XDH. The enzyme catalyzes the oxidation of hypoxanthine to xanthine and also xanthine to uric acid by an oxidative hydroxylation mechanism. The present electrochemical biosensor was optimized in terms of applied potential and pH. The electrocatalytic oxidation response showed a linear dependence on the xanthine concentration ranging from 1.0 × 10(-5) to 1.8 × 10(-3) M with a correlation coefficient of 0.994. The modified electrode shows a very low detection limit for xanthine of 0.25 nM (signal-to-noise ratio = 3) using controlled potential amperometry. PMID:23134312

Kalimuthu, Palraj; Leimkühler, Silke; Bernhardt, Paul V

2012-12-01

385

Enzyme engineering by targeted libraries.  

PubMed

This review outlines the strategies we apply for directed enzyme evolution using targeted libraries, namely, libraries that diversify specific residues with predefined mutational compositions. The theoretical grounds underlining the design of such libraries are described, including the mutational load, the ratio of beneficial versus deleterious mutations, and screening capacity. We point out the advantage of using mutational spiking strategies for "hedging the bets," exploring a large number of potentially beneficial mutations, and tuning the library's mutational load. Also highlighted are the merits of low-throughput screens that measure multiple parameters at high accuracy, and of using the desired substrate and reaction conditions rather than surrogates. We subsequently describe library construction strategies (rational and analytical) based on structure and sequence analyses, including ancestral libraries, which are particularly suitable for low-throughput screens. We also discuss the critical role of including compensatory, stabilizing mutations during library construction. Finally, the design efficiency and the optimal mutational loads of libraries are assessed by comparing targeted mutational libraries versus libraries of random mutations. PMID:23422434

Goldsmith, Moshe; Tawfik, Dan S

2013-01-01

386

Enzyme Technology Digest. An Information Exchange in Enzyme Technology. Volume 5, Number 2, July 1976.  

National Technical Information Service (NTIS)

Enzyme Technology Digest, an information exchange in enzyme technology, is issued three times a year. This issue includes feature articles on the following topics: Diseases resulting from enzymatic deficiencies in lysosomes catabolizing gangliosides; and ...

H. Sobel E. Lawton

1976-01-01

387

23 CFR 633.211 - Implementation of the 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. 633.211 Section...Clean Air Act and the Federal Water Pollution Control Act. Pursuant to regulations...Clean Air Act and the Federal Water Pollution Control Act are included in...

2010-04-01

388

MauG: a di-heme enzyme required for methylamine dehydrogenase maturation  

PubMed Central

Methylamine dehydrogenase (MADH) requires the cofactor tryptophan tryptophylquinone (TTQ) for activity. TTQ is a posttranslational modification that results from an 8-electron oxidation of two specific tryptophans in the MADH ?-subunit. The final 6-electron oxidation is catalyzed by an unusual c-type di-heme enzyme, MauG. The di-ferric enzyme can react with H2O2, but atypically for c-type hemes the di-ferrous enzyme can react with O2 as well. In both cases, an unprecedented bis-Fe(IV) redox state is formed, composed of a ferryl heme (Fe(IV)=O) and the second heme as Fe(IV) stabilized by His–Tyr axial ligation. Bis-Fe(IV) MauG acts as a potent 2-electron oxidant. Catalysis is long-range and requires a hole hopping electron transfer mechanism. This review highlights the current knowledge and focus of research into this fascinating system.

Wilmot, Carrie M.; Yukl, Erik T.

2012-01-01

389

Eptastigmine, nicotinamide and nicotinic acid determination using an inhibition enzyme sensor; application to pharmaceutical analysis.  

PubMed

An enzyme inhibition biosensor, developed in our laboratory and previously used for the analysis of compounds with anticholinesterase activity (e.g. physostigmine, neostigmine, pyridostigmine nicotine and organophosphorus compounds) has now been tested for the analysis of another recently synthesized cholinesterase inhibitor, i.e. eptastigmine. In addition nicotinic acid and nicotinamide, although displaying weaker inhibition properties, were also tested in pharmaceutical products using the same inhibition enzyme sensor. The biosensor consisted of a hydrogen peroxide amperometric electrode coupled to a functionalised nylon membrane chemically bonding both the enzymes butyrylcholinesterase and choline oxidase; a butyrylcholine standard solution in glycine buffer acted as substrate. The response of the system to all the inhibitors considered was characterised completely and the analysis of several pharmaceutical formulations containing nicotinamide or nicotinic acid was also performed. PMID:12073883

Campanella, Luigi; Cocco, Roberto; Favero, Gabriele; Sammartino, Maria Pia; Tomassetti, Mauro

2002-04-01

390

Characterization of Xylanolytic Enzymes for Potential Applications,  

National Technical Information Service (NTIS)

In the study the enzymatic hydrolysis of xylans was shown to be influenced by the heterogeneous structure of the substrate. The role of individual xylan-degrading enzymes in the hydrolysis of xylans was studied using enzyme mixtures of different microbial...

K. Poutanen

1988-01-01

391

Chemical probes for histone-modifying enzymes  

Microsoft Academic Search

The histone-modifying enzymes that catalyze reversible lysine acetylation and methylation are central to the epigenetic regulation of chromatin remodeling. 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 investigation of the structure and function of these lysine-modifying enzymes. This review summarizes progress to date

Philip A Cole

2008-01-01

392

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

393

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

394

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

395

Labeled substrate conjugates for identifying enzyme inhibitors  

US Patent & Trademark Office Database

This invention provides labeled-substrate conjugates for assaying enzymes, particularly neuraminidases. Also provided are assays that are useful for identifying compounds that inhibit sialyltransferases or neuraminidases and may be useful in treating subjects with influenza. In particular, the present invention relates to methods of using such labeled substrate conjugates to screen for enzyme inhibitors, particularly in a high-throughput format.

2009-05-05

396

Orphan enzymes in ether lipid metabolism  

PubMed Central

Ether lipids are an emerging class of lipids which have so far not been investigated and understood in every detail. They have important roles as membrane components of e.g. lens, brain and testis, and as mediators such as platelet-activating factor. The metabolic enzymes for biosynthesis and degradation have been investigated to some extent. As most involved enzymes are integral membrane proteins they are tricky to handle in biochemical protocols. The sequence of some ether lipid metabolising enzymes has only recently been reported and other sequences still remain obscure. Defined enzymes without assigned sequence are known as orphan enzymes. One of these enzymes with uncharacterised sequence is plasmanylethanolamine desaturase, a key enzyme for the biosynthesis of one of the most abundant phospholipids in our body, the plasmalogens. This review aims to briefly summarise known functions of ether lipids, give an overview on their metabolism including the most prominent members, platelet-activating factor and the plasmalogens. A special focus is set on the description of orphan enzymes in ether lipid metabolism and on the successful strategies how four previous orphans have recently been assigned a sequence. Only one of these four was characterised by classical protein purification and sequencing, whereas the other three required alternative strategies such as bioinformatic candidate gene selection and recombinant expression or development of an inhibitor and multidimensional metabolic profiling.

Watschinger, Katrin; Werner, Ernst R.

2013-01-01

397

Development of a microfluidic immobilised enzyme reactor.  

PubMed

A microfluidic immobilised enzyme reactor consisting of a catalytically functionalised microstructure fabricated from silicone rubber material was used for steady-state kinetic characterisation of a thermophilic beta-glycosidase under pressure-driven flow conditions and continuous conversion of lactose by this enzyme at 80 degrees C. PMID:17563818

Thomsen, Malene S; Pölt, Peter; Nidetzky, Bernd

2007-06-28

398

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

399

Cobalamin- and Corrinoid-Dependent Enzymes  

PubMed Central

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

Matthews, Rowena G.

2011-01-01

400

Enzyme Induction in Man caused by Smoking  

Microsoft Academic Search

HIGHER animals may change in their response to drugs because of a decrease in the sensitivity of drug receptor sites in the organism, or because of accelerated drug metabolism. The latter has been explained1 on the basis of drug induced stimulation of liver microsomal enzymes, for example, many compounds have been listed which induce microsomal oxidizing enzymes in rats, and

A. H. Beckett; E. J. Triggs

1967-01-01

401

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.

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

2010-01-01

402

Intrinsic dynamics of an enzyme underlies catalysis  

Microsoft Academic Search

A unique feature of chemical catalysis mediated by enzymes is that the catalytically reactive atoms are embedded within a folded protein. Although current understanding of enzyme function has been focused on the chemical reactions and static three-dimensional structures, the dynamic nature of proteins has been proposed to have a function in catalysis. The concept of conformational substates has been described;

Elan Z. Eisenmesser; Oscar Millet; Wladimir Labeikovsky; Dmitry M. Korzhnev; Magnus Wolf-Watz; Daryl A. Bosco; Jack J. Skalicky; Lewis E. Kay; Dorothee Kern

2005-01-01

403

Enzyme adsorption at solid-liquid interfaces  

Microsoft Academic Search

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

S. Duinhoven

1992-01-01

404

Immobilized enzymes and cells as practical catalysts  

Microsoft Academic Search

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

A. M. Klibanov

1983-01-01

405

Method for Insolubilizing Enzymes on Chitosan.  

National Technical Information Service (NTIS)

Insolubilized but active enzymes are prepared according to this patent application by mixing an aqueous solution of the enzyme with an aqueous solution of chitosan and then adding a polyfunctional cross-linking agent to form a gel. The so produced gel is ...

M. S. Masri V. G. Randall W. L. Stanley

1976-01-01

406

Design and operation of immobilized enzyme reactors  

Microsoft Academic Search

This review encompasses recent advances in the design and operation of immobilized enzyme reactors for industrial applications. Basic immobilized enzyme reactor engineering concepts are described as a reference point for recent innovations. Although practical examples are cited, the subject is approached from the viewpoint of reactor design and operation and the potential general applicability of new concepts or developments. Areas

407

Immobilized Enzymes and Cells as Practical Catalysts  

Microsoft Academic Search

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

Alexander M. Klibanov

1983-01-01

408

Scaling up an Immobilized Enzyme System  

Microsoft Academic Search

The development of an immobilized enzyme system for commercial application involves a series of decisions and compromises beginning with the choice of enzyme support and ending with the decision on operational mode. Each step is dependent on the other steps, and all the steps influence the overall economics of the final process. Compromises need to be made about the support,

Howard H. Weetall; Wayne H. Pitcher

1986-01-01

409

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

PubMed

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

Cronan, John E

2014-06-01

410

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...

411

Phenylalanine Depletion for the Management of Phenylketonuria: Use of Enzyme Reactors with Immobilized Enzymes  

Microsoft Academic Search

Multitubular enzyme reactors with immobilized phenylalanine ammonia lyase were tested in vitro and in vivo for depletion of phenylalanine in circulating blood. Sustained reduction of phenylalanine was achieved in less than 30 minutes. A 50 percent decrease of phenylalanine was obtained with a 2-hour application of enzyme reactors and was maintained for more than 2 days. Similar enzyme reactors have

Clara M. Ambrus; Julian L. Ambrus; Csaba Horvath; Henrik Pedersen; Satya Sharma; Christopher Kant; Edwin Mirand; Robert Guthrie; Thomas Paul

1978-01-01

412

The Genetic Privacy Act and commentary  

SciTech Connect

The Genetic Privacy Act is a proposal for federal legislation. The Act is based on the premise that genetic information is different from other types of personal information in ways that require special protection. Therefore, to effectively protect genetic privacy unauthorized collection and analysis of individually identifiable DNA must be prohibited. As a result, the premise of the Act is that no stranger should have or control identifiable DNA samples or genetic information about an individual unless that individual specifically authorizes the collection of DNA samples for the purpose of genetic analysis, authorized the creation of that private information, and has access to and control over the dissemination of that information.

Annas, G.J.; Glantz, L.H.; Roche, P.A.

1995-02-28

413

The Dutch Euthanasia Act: recent legal developments.  

PubMed

The Dutch Termination of Life on Request and Assisted Suicide Act [Wet toetsing levensbeëindiging op verzoek en hulp bij zelfdoding (Wtl)] came into force in 2002. Its aim is to increase the degree of due care exercised by physicians when terminating a patient's life and to provide a legal framework within which physicians account for their actions in such cases. On the basis of the second evaluation of the Act, published in December 2012, this article provides an overview of the most recent legal developments regarding the Dutch Euthanasia Act. Special attention is given to patients with dementia, psychiatric patients and patient who are "weary of life". PMID:24437331

Legemaate, Johan; Bolt, Ineke

2013-12-01

414

The Patient Self-Determination Act.  

PubMed

The Patient Self-Determination Act was signed into law in November 1990 to take effect in December 1991. The Act marked Congress's first legislative action related to life-sustaining medical treatment. It requires every health care facility that participates in Medicare or Medicaid to inform adult patients about advance directives. McCloskey discusses the legislative process leading to passage of the Act; pro-life groups' opposition to federal support of advance directives; provider groups' skepticism toward the perceived administrative burden of federal intervention; and professor Alexander Capron's preference for existing voluntary efforts over premature legislation. PMID:10113825

McCloskey, E L

1991-06-01

415

High Bit Rate Experiments Over ACTS  

NASA Technical Reports Server (NTRS)

This paper describes two high data rate experiments chat are being developed for the gigabit NASA Advanced Communications Technology Satellite (ACTS). The first is a telescience experiment that remotely acquires image data at the Keck telescope from the Caltech campus. The second is a distributed global climate application that is run between two supercomputer centers interconnected by ACTS. The implementation approach for each is described along with the expected results. Also. the ACTS high data rate (HDR) ground station is also described in detail.

Bergman, Larry A.; Gary, J. Patrick; Edelsen, Burt; Helm, Neil; Cohen, Judith; Shopbell, Patrick; Mechoso, C. Roberto; Chung-Chun; Farrara, M.; Spahr, Joseph

1996-01-01

416

Biotechnological uses of enzymes from psychrophiles  

PubMed Central

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

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

2011-01-01

417

Enzymic Conversion of Racemates into Aminoacid Enantiomers  

NASA Astrophysics Data System (ADS)

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

Švedas, V.; Galaev, I. U.

1983-12-01

418

Structural basis for enzyme I inhibition by ?-ketoglutarate  

PubMed Central

Creating new bacterial strains in which carbon and nitrogen metabolism are uncoupled, is potentially very useful for optimizing yields of microbial produced chemicals from renewable carbon sources. The mechanisms, however, that balance carbon and nitrogen consumption in bacteria are poorly understood. Recently, ?-ketoglutarate (?KG), the carbon substrate for ammonia assimilation, has been observed to inhibit Escherichia coli enzyme I (EI), the first component of the bacterial phosphotransferase system (PTS), thereby providing a direct biochemical link between central carbon and nitrogen metabolism. Here we investigate the EI-?KG interaction by NMR and enzymatic assays. We show that ?KG binds with a KD ~ 2.2 mM at the active site of EI, acting as a competitive inhibitor. In addition, we use molecular docking simulations to derive a structural model of the enzyme-inhibitor complex that is fully consistent with NMR and analytical ultracentrifugation data. We expect that the EI-?KG structure presented here will provide a starting point for structure-based design of EI mutants resistant to ?KG.

Venditti, Vincenzo; Ghirlando, Rodolfo; Clore, G. Marius

2013-01-01

419

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.

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

420

Angiotensin I converting enzyme inhibitory peptide extracted from freshwater zooplankton.  

PubMed

In this study, hydrolysates obtained from the freshwater rotifer Brachionus calyciflonus were investigated for angiotensin I converting enzyme (ACE) inhibitory peptides. Freshwater rotifer protein was hydrolyzed using six separate enzymes in a batch reactor. The peptic hydrolysate had the highest ACE inhibitory activity compared to the other hydrolysates. The highest ACE inhibitory peptide was separated using Sephadex G-25 column chromatography and high-performance liquid chromatography on a C18 column. The 50% inhibitory concentration (IC(50)) value of purified ACE inhibitory peptide was 40.01 microg/mL. ACE inhibitory peptide was identified as being seven amino acid residues of Ala-Gln-Gly-Glu-Arg-His-Arg by N-terminal amino acid sequence analysis. The IC(50) value of purified ACE inhibitory peptide was 47.1 microM, and Lineweaver-Burk plots suggested that the peptide purified from rotifer protein acts as a competitive inhibitor against ACE. The results of this study suggest that peptides derived from freshwater rotifers may be beneficial as antihypertension compounds in functional foods or as pharmaceuticals. PMID:20170338

Lee, Jung Kwon; Lee, Min-Su; Park, Heum Gi; Kim, Se-Kwon; Byun, Hee-Guk

2010-04-01

421

Ruminant Nutrition Symposium: Improving cell wall digestion and animal performance with fibrolytic enzymes.  

PubMed

This paper aimed to summarize published responses to treatment of cattle diets with exogenous fibrolytic enzymes (EFE), to discuss reasons for variable EFE efficacy in animal trials, to recommend strategies for improving enzyme testing and EFE efficacy in ruminant diets, and to identify proteomic differences between effective and ineffective EFE. A meta-analysis of 20 dairy cow studies with 30 experiments revealed that only a few increased lactational performance and the response was inconsistent. This variability is attributable to several enzyme, feed, animal, and management factors that were discussed in this paper. The variability reflects our limited understanding of the synergistic and sequential interactions between exogenous glycosyl hydrolases, autochthonous ruminal microbes, and endogenous fibrolytic enzymes that are necessary to optimize ruminal fiber digestion. An added complication is that many of the standard methods of assaying EFE activities may over- or underestimate their potential effects because they are based on pure substrate saccharification and do not simulate ruminal conditions. Our recent evaluation of 18 commercial EFE showed that 78 and 83% of them exhibited optimal endoglucanase and xylanase activities, respectively, at 50 °C, and 77 and 61% had optimal activities at pH 4 to 5, respectively, indicating that most would likely act suboptimally in the rumen. Of the many fibrolytic activities that act synergistically to degrade forage fiber, the few usually assayed, typically endoglucanase and xylanase, cannot hydrolyze the recalcitrant phenolic acid-lignin linkages that are the main constraints to ruminal fiber degradation. These factors highlight the futility of random addition of EFE to diets. This paper discusses reasons for the variable animal responses to dietary addition of fibrolytic enzymes, advances explanations for the inconsistency, suggests a strategy to improve enzyme efficacy in ruminant diets, and describes differences among the proteomes of effective and ineffective EFE. PMID:24663173

Adesogan, A T; Ma, Z X; Romero, J J; Arriola, K G

2014-04-01

422

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

PubMed Central

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

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

2000-01-01

423

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.

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

2013-01-01

424

Exploring the evolution of novel enzyme functions within structurally defined protein superfamilies.  

PubMed

In order to understand the evolution of enzyme reactions and to gain an overview of biological catalysis we have combined sequence and structural data to generate phylogenetic trees in an analysis of 276 structurally defined enzyme superfamilies, and used these to study how enzyme functions have evolved. We describe in detail the analysis of two superfamilies to illustrate different paradigms of enzyme evolution. Gathering together data from all the superfamilies supports and develops the observation that they have all evolved to act on a diverse set of substrates, whilst the evolution of new chemistry is much less common. Despite that, by bringing together so much data, we can provide a comprehensive overview of the most common and rare types of changes in function. Our analysis demonstrates on a larger scale than previously studied, that modifications in overall chemistry still occur, with all possible changes at the primary level of the Enzyme Commission (E.C.) classification observed to a greater or lesser extent. The phylogenetic trees map out the evolutionary route taken within a superfamily, as well as all the possible changes within a superfamily. This has been used to generate a matrix of observed exchanges from one enzyme function to another, revealing the scale and nature of enzyme evolution and that some types of exchanges between and within E.C. classes are more prevalent than others. Surprisingly a large proportion (71%) of all known enzyme functions are performed by this relatively small set of 276 superfamilies. This reinforces the hypothesis that relatively few ancient enzymatic domain superfamilies were progenitors for most of the chemistry required for life. PMID:22396634

Furnham, Nicholas; Sillitoe, Ian; Holliday, Gemma L; Cuff, Alison L; Laskowski, Roman A; Orengo, Christine A; Thornton, Janet M

2012-01-01

425

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

426

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

427

Aromatase and COX in Breast Cancer: Enzyme inhibitors and beyond  

PubMed Central

Aromatase expression and enzyme activity in breast cancer patients is greater in or near the tumor tissue compared with the normal breast tissue. Complex regulation of aromatase expression in human tissues involves alternative promoter sites that provide tissue-specific control. Previous studies in our laboratories suggested a strong association between aromatase (CYP19) gene expression and the expression of cyclooxygenase (COX) genes. Additionally, nonsteroidal anti-inflammatory drugs (NSAIDs) and COX selective inhibitors can suppress CYP19 gene expression and decrease aromatase activity. Our current hypothesis is that pharmacological regulation of aromatase and/or cyclooxygenases can act locally to decrease the biosynthesis of estrogen and may provide additional therapy options for patients with hormone-dependent breast cancer. Two pharmacological approaches are being developed, one involving mRNA silencing by selective siRNA molecules and the second utilizing small molecule drug design. In the first approach, short interfering RNAs (siRNA) were designed against either human aromatase mRNA or human COX-2 mRNA. Treatment of breast cancer cells with siAROMs completely masked the aromatase enzyme activity. Treatment with COX-2 siRNAs decreased the expression of COX-2 mRNA; furthermore, the siCOX-2-mediated decrease also resulted in suppression of CYP19 mRNA. The small molecule drug design approach focuses on the synthesis and biological evaluation of a novel series of sulfonanilide analogs derived from the COX-2 selective inhibitors. The compounds suppress aromatase enzyme activity in SK-BR-3 breast cancer cells in a dose and time dependent manner, and structure activity analysis does not find a correlation between aromatase suppression and COX inhibition. Real-time PCR analysis demonstrates that the sulfonanilide analogs decrease aromatase gene transcription in breast cells. Thus, these results suggest that the siRNAs and novel sulfonanilides targeting aromatase expression may be valuable tools for selective regulation of aromatase in breast cancer.

Brueggemeier, Robert W.; Su, Bin; Sugimoto, Yasuro; Diaz-Cruz, Edgar S.; Davis, Danyetta D.

2009-01-01

428

76 FR 16771 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013

...BANK OF THE UNITED STATES Sunshine Act Meeting...Notice of a Partially Open Meeting of the Board...Export-Import Bank of the United States...Washington, DC 20571. OPEN AGENDA ITEMS: Item No. 1: Local Cost Policy. PUBLIC...

2011-03-25

429

76 FR 63333 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013

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2011-10-12

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Federal Register 2010, 2011, 2012, 2013

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2011-03-30

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2012-04-13

432

76 FR 7562 - Sunshine Act Meeting  

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2011-02-10

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77 FR 15592 - Privacy Act; Implementation  

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2012-03-16

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77 FR 15594 - Privacy Act; Implementation  

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2012-03-16

435

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2012-03-16

436

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2013-01-24

437

43 CFR 9212.1 - Prohibited acts.  

Code of Federal Regulations, 2010 CFR

...INTERIOR TECHNICAL SERVICES (9000) FIRE MANAGEMENT Wildfire Prevention § 9212.1 Prohibited acts. Unless permitted...authorized officer, it is prohibited on the public lands to: (a) Cause a fire, other than a campfire, or the industrial...

2009-10-01

438

43 CFR 9212.1 - Prohibited acts.  

Code of Federal Regulations, 2010 CFR

...INTERIOR TECHNICAL SERVICES (9000) FIRE MANAGEMENT Wildfire Prevention § 9212.1 Prohibited acts. Unless permitted...authorized officer, it is prohibited on the public lands to: (a) Cause a fire, other than a campfire, or the industrial...

2010-10-01

439

Preventive Care for Children (Affordable Care Act)  

MedlinePLUS

... Myspace Close Text Size: A A A Preventive Care for Children Many insurers are now required to ... Services Task Force Recommendations . Fact Sheet: The Affordable Care Act and Immunization Fact Sheet: The Affordable Care ...

440

78 FR 73210 - Sunshine Act Meeting  

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...and to discuss prospective funders for LSC's 40th anniversary celebration and development activities and prospective members for LSC's 40th Campaign Cabinet and Honorary...Consider and act on proposed changes to LSC's case statement for fundraising 6....

2013-12-05

441

77 FR 10574 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013

...notice and comment, publication requirement of the LSC Act and Board review of LSC promulgations: [ssquf] Mattie Cohan, Office of Legal Affairs. 5. Staff report on LSC Continuity of Operations Plan. 6. Public...

2012-02-22

442

76 FR 78701 - Sunshine Act Meeting Notice  

Federal Register 2010, 2011, 2012, 2013

...Operations & Regulations Committee on changes to LSC Bylaws. 3. Consider and act on ratification of LSC's solicitation of contribution from Friends...electronic mail to FR_NOTICE_QUESTIONS@lsc.gov. ACCESSIBILITY: LSC complies with...

2011-12-19

443

77 FR 2092 - Sunshine Act Meeting Notice  

Federal Register 2010, 2011, 2012, 2013

...public to hear briefings from management and LSC's Inspector General, to consider and...potential and pending litigation involving LSC, and to consider and act on the request...authorization to accept compensation for non-LSC...

2012-01-13

444

Affordable Care Act Overview: Selected Provisions  

MedlinePLUS

... quality & efficiency More people covered Greater focus on public health & prevention Insurance exchanges Guaranteed issue Preventive services cov’ ... org/advocacy/Health+Reform/ for more ACA resources. Public health workforce devel. Affordable Care Act Overview Selected Provisions ...

445

NSF Acting Head Mulls Job, Science Issues  

ERIC Educational Resources Information Center

Richard C. Atkinson, acting head of the National Science Foundation, gives his views on problems facing NSF and the science community and predicts growing support for basic research in the next decade. (MLH)

Zerkel, Fred H.

1976-01-01

446

78 FR 21419 - Sunshine Act Meetings  

Federal Register 2010, 2011, 2012, 2013

...Operating Budget for FY 2013 and recommend Resolution 2013-XXX to the full Board David Richardson, Treasurer/Comptroller...Advancement Committee 14. Consider and act on Resolution 2013-XXX in recognition of distinguished service by Victor M....

2013-04-10

447

77 FR 57017 - Privacy Act; Implementation  

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2012-09-17

448

76 FR 4395 - Sunshine Act Meetings  

Federal Register 2010, 2011, 2012, 2013

...senior-level appointment. CONTACT PERSON FOR MORE INFORMATION: Brian Corcoran, Acting General Counsel, Postal Regulatory Commission, 901...Washington, DC 20268-0001, 202-789-6820 or brian.corcoran@prc.gov. Dated: January 20, 2011. Shoshana M....

2011-01-25

449

75 FR 17849 - Freedom of Information Act  

Federal Register 2010, 2011, 2012, 2013

...have a significant economic impact on a substantial number of...agency prepare a budgetary impact statement before promulgating...any one year. If a budgetary impact statement is required, Section...Administrative practice and procedure, Freedom of Information Act,...

2010-04-08

450

75 FR 19972 - Sunshine Act Meetings  

Federal Register 2010, 2011, 2012, 2013

...Acting Director, Office of Thrift Supervision), concurred in by Director Thomas J. Curry (Appointive), Director John C. Dugan (Comptroller of the Currency), and Chairman Sheila C. Bair, that Corporation business required its consideration of...

2010-04-16

451

75 FR 40834 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013

...Appointive), concurred in by Director John E. Bowman (Acting Director, Office of Thrift Supervision), Director John C. Dugan (Comptroller of the Currency), and Chairman Sheila C. Bair, that Corporation business required its consideration of...

2010-07-14

452

75 FR 36088 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013

...Gruenberg, concurred in by Director John E. Bowman (Acting Director, Office of Thrift Supervision), Director John C. Dugan (Comptroller of the Currency), and Chairman Sheila C. Bair, that Corporation business required its consideration of...

2010-06-24

453

75 FR 48968 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013

...seconded by Director John E. Bowman (Acting Director, Office of Thrift Supervision), concurred in by Director John C. Dugan (Comptroller of the Currency), Vice Chairman Martin J. Gruenberg, and Chairman Sheila C. Bair, that Corporation...

2010-08-12

454

75 FR 40834 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013

...Acting Director, Office of Thrift Supervision), concurred in by Director Thomas J. Curry (Appointive), Director John C. Dugan (Comptroller of the Currency), and Chairman Sheila C. Bair, that Corporation business required its consideration of...

2010-07-14

455

Criminal Acts against Civil Aviation, 1988.  

National Technical Information Service (NTIS)

The Federal Aviation Administration's Office of Civil Aviation Security maintains records of aircraft hijackings, bombing attacks, and other significant criminal acts against civil aviation worldwide. These records include actual and attempted hijackings;...

1988-01-01

456

Criminal Acts against Civil Aviation, 1986.  

National Technical Information Service (NTIS)

The Federal Aviation Administration's Office of Civil Aviation Security maintains a record of aircraft hijackings and other significant criminal acts against civil aviation worldwide. These records include actual and attempted hijackings, explosions aboar...

1986-01-01

457

Research on State Regulatory Flexibility Acts.  

National Technical Information Service (NTIS)

The Regulatory Flexibility Act of 1980, as amended, established a process of analyzing and mitigating impacts of federal regulations on small businesses and other small entities. In the ensuing years, states began adopting regulatory flexibility legislati...

2013-01-01

458

Characterization of Esterases Acting on Hemicelluloses.  

National Technical Information Service (NTIS)

Xylans and mannans contain different esterified substituents such as acetyl, feruloyl and p-coumaroyl side groups. The properties and function of hemicellulose-acting esterases of Trichoderma reesei and Aspergillus oryzae were studied in this work. Both f...

M. Tenkanen

1995-01-01

459

75 FR 57953 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013

...Dodd-Frank Reform Act for System Organization and Staffing. FOR FURTHER INFORMATION CONTACT: Michelle Smith, Director, or Dave Skidmore, Assistant to the Board, Office of Board Members at 202-452- 2955. SUPPLEMENTARY INFORMATION: You may call...

2010-09-23

460

77 FR 1095 - Sunshine Act Meeting  

Federal Register 2010, 2011, 2012, 2013

...the related annual accounting support fee for the Board under Section 109 of the Sarbanes-Oxley Act of 2002. Commissioner Paredes, as duty officer, determined that no earlier notice thereof was possible. At times, changes in Commission priorities...

2012-01-09

461

75 FR 1009 - Sunshine Act Meeting Notice  

Federal Register 2010, 2011, 2012, 2013

...Investment Company Act Section 34(b) and, if so, whether and to what extent sanctions should be imposed on her. Commissioner Paredes, as duty officer, determined that no earlier notice thereof was possible. At times, changes in Commission priorities...

2010-01-07

462

78 FR 69291 - Privacy Act; Implementation  

Federal Register 2010, 2011, 2012, 2013

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2013-11-19

463

78 FR 69289 - Privacy Act; Implementation  

Federal Register 2010, 2011, 2012, 2013

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2013-11-19

464

75 FR 34634 - Privacy Act; Implementation  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF DEFENSE National Geospatial-Intelligence Agency 32 CFR Part 320 Privacy Act; Implementation...revise ``NIMA'' to read ``NGA''. PART 320--NATIONAL GEOSPATIAL-INTELLIGENCE AGENCY (NGA) PRIVACY [FR Doc....

2010-06-18

465

78 FR 8538 - Privacy Act of 1974  

Federal Register 2010, 2011, 2012, 2013

...Medicare & Medicaid Services Privacy Act of...Department of Health and Human Services (HHS), Centers...secure electronic interface established in...secure electronic interface is the same one...through the Data Services Hub...

2013-02-06

466

75 FR 28594 - Sunshine Act Notice  

Federal Register 2010, 2011, 2012, 2013

...for updating the National Voter Registration Act (NVRA) regulations; and a discussion on Election Management Guidelines (EMG) chapters on accessibility, election office administration, and technology in elections. Commissioners will consider...

2010-05-21

467

Faces of the Recovery Act: 1366 Technologies  

ScienceCinema

LEXINGTON, MA - At 1366 Technologies, Ely Sachs and Frank van Mierlo are using ARPA-E Recovery Act funding to dramatically reduce the costs of solar panel production. To read more about the project: http://arpa-e.energy.gov/FundedProjects.aspx#1366 To see more projects funded by the Recovery Act through ARPA-E: http://arpa-e.energy.gov/FundedProjects.aspx

Sachs, Ely; Mierlo, Frank van; Obama, Barack

2013-05-29

468

Anti-utility act of 1982  

Microsoft Academic Search

Angered by the Tax Equity and Fiscal Responsibility Act of 1982, electric-utility executives and lobbyists are protesting to Congress and the administration that Senator Dole's bill eliminates most of the benefits of the Economic Recovery Tax Act of 1981. Utilities object strenuously to repeal of the tax-free dividend-reinvestment program, the reduction in investment tax credits that will cost them heavily

McCaughey

1982-01-01

469

Faces of the Recovery Act: 1366 Technologies  

SciTech Connect

LEXINGTON, MA - At 1366 Technologies, Ely Sachs and Frank van Mierlo are using ARPA-E Recovery Act funding to dramatically reduce the costs of solar panel production. To read more about the project: http://arpa-e.energy.gov/FundedProjects.aspx#1366 To see more projects funded by the Recovery Act through ARPA-E: http://arpa-e.energy.gov/FundedProjects.aspx

Sachs, Ely; Mierlo, Frank van; Obama, Barack

2010-01-01

470

A survey of orphan enzyme activities  

PubMed Central

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

Pouliot, Yannick; Karp, Peter D

2007-01-01

471

Enzyme reaction annotation using cloud techniques.  

PubMed

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

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

2013-01-01

472

A qualitative approach to enzyme inhibition.  

PubMed

Most general biochemistry textbooks present enzyme inhibition by showing how the basic Michaelis-Menten parameters K(m) and V(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 kinetic aspects of an enzyme. The discussion here describes a qualitative approach to teaching enzyme inhibition that allows for a physical or mechanistic understanding. This qualitative approach to enzyme inhibition starts by recognizing that the two fundamental kinetic parameters of an enzyme catalyzed reaction are V(max) and V(max) /K(m) , which correspond to the apparent rates of reaction at very high and very low concentrations of substrate, respectively. It just so happens that the reciprocals of V(max) and V(max) /K(m) correspond to the y-intercept and slope of the Lineweaver-Burk plot, respectively. Thus, an inhibitor that affects the y-intercept binds to the enzyme at very high substrate concentrations, and thus binds to the enzyme-substrate complex, while an inhibitor that affects the slope binds to the enzyme at very low substrate concentrations, and thus binds only to free enzyme. These simple precepts can be used to interpret the basic inhibition patterns, competitive, uncompetitive and noncompetitive, and more importantly, derive mechanistic information, especially in multisubstrate reactions. The application of these principles is illustrated by using an example from cancer chemotherapy, the inhibition of thymidylate synthase by 5-fluorouracil and leucovorin. PMID:21567682

Waldrop, Grover L

2009-01-01

473

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

474

Children's Internet Protection Act Deemed Unconstitutional  

NSDL National Science Digital Library

This morning, three federal judges overturned the Children's Internet Protection Act and ruled that public libraries cannot be forced to use Internet filters designed to block pornography. In the 195-page decision, judges asserted that the Act went too far because the filters could also block access to other legitimate sites, which is a violation of the First Amendment. The Act, which was signed by President Clinton in 2000 and widely criticized by First Amendment advocates, would have required public libraries to install the Internet filters, or risk losing federal funding. This recent decision has been applauded by the American Library Association (ALA) and the American Civil Liberties Union (ACLU), which contends that the law is "unenforceable, unconstitutional, vague and overbroad." Furthermore, they argue that it denies "poor people without home computers the same access to information as their wealthier neighbors because the software could mistakenly block Web sites on issues such as breast cancer and homosexuality."Prior to the Children's Internet Protection Act, two other anti-Internet pornography laws were brought before federal judges for constitutional challenges, and overturned. In 1996, the Communications Decency Act (which made it a crime to put adult-oriented material online where children can find it), was declared unconstitutional by the Supreme Court; and in 1998, the 3rd US Circuit Court of Appeals overturned the Child Online Protection Act (which required Web sites to collect a credit card number or other proof of age before allowing Internet users to view material deemed "harmful to minors"), stating it was too broad and vague. For more information on the recent court decision regarding the Children's Internet Protection Act, viewers can access the first link above. The second link provides access to a full copy of the court's decision on the case. Links three and four lead to home pages of the American Library Association and the American Civil Liberties Union, respectively. Lastly, links five, six, and seven provide access to copies of the Children's Internet Protection Act; the 1998 House of Representatives report on the Child Online Protection Act; and the 1996 Communications Decency Act, respectively.

Green, Marcia.

2002-01-01

475

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

476

Highlights of the Clean Water Act of 1977  

Microsoft Academic Search

Amendments to the Federal Water Pollution Control Act Amendments of 1972 (hereinafter 1972 Act), passed by Congress on December 15, 1977, were signed by President Carter on December 28, 1977 (hereinafter 1977 Act). The amendments, which change the popular name of the Federal Water Pollution Control Act to the Clean Water Act, represent a compromise between environmentalists and industry and

Kerner

2009-01-01

477

The Nuclear Waste Policy Act, as amended, with appropriations acts appended. Revision 1  

SciTech Connect

This act provides for the development of repositories for the disposal of high-level radioactive wastes, low-level radioactive wastes, and spent nuclear fuels. In addition, it establishes research and development programs, as well as demonstration programs regarding the disposal of these wastes. This Act consists of the Act of Jan. 7, 1983 (Public Law 97-425; 96 Stat. 2201), as amended by Public Law 100-203 and Public Law 102-486.

NONE

1995-02-01

478

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

PubMed

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

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

2012-12-01

479

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.

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

2013-01-01

480

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.

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

1996-01-01

481

Kallikrein-like prorenin-converting enzymes in inbred hypertensive mice.  

PubMed

Kallikreins are a group of serine proteases and are distinguished by having serine residue at their active site. Their general function is to convert inactive pro-peptide into its biologically active form. In recent years, emerging evidence indicates that some kallikrein-kinin enzymes also play a role in the modulation of renin-angiotensin system. These kallikrein-like prorenin converting enzymes act on renin-angiotensin by converting prorenin into biologically active renin. In this investigation, kallikrein-like prorenin converting enzyme (PRCE C) (mK9) is isolated from genetically inbred high blood pressure (BPH) and their normal counterparts (BPN) mice, and its protein levels are quantitated. Levels of mRNA expression are also compared. Additionally, localization of the enzyme is visualized by in situ hybridization histochemistry. Results indicated higher levels of PRCE C (mK9) enzyme in BPH mice in comparison to their normal counterparts. mRNA expression was also higher in BPH mice. In situ hybridization histochemistry results localized PRCE C (mK9) in the striated duct cells of submandibular gland. PMID:12727215

Uddin, Mukarram; Polley-Mandal, M; Beg, O U

2003-05-16

482

Drugs impact on CYP-450 enzyme family: A pharmacogenetical study of response variation  

PubMed Central

Pharmacogenetics is the study of genetic basis in the individual response to drugs. A thorough knowledge of this will lead to a future where tailor-made drugs, suiting an individual, can be used. Scandinavian countries have been known for wide usage of pharmacogenetics and the most widely used application is for genotyping CYP2D6 in treating psychiatric illness. The CYP-450 enzyme, a super family of microsomal drug-metabolizing enzymes, is the most important of enzymes that catalyzes phase-I drug metabolism reaction. CYP2D6 is a member of this family and it has been most intensively studied and the best example of pharmacogenetics variation in drug metabolism. Neuro-transmitter and drug acting CNS viz. codeine, dextromethorphan, metoprolol and tryptyline etc. are well metabolized by this enzyme. Thus, CYP2D6 is one of the most important and responsible enzymes which regulates bioavailability and metabolism of drug. Presently 75 alleles of CYP2D6 have been described which are responsible for variance of metabolism and toxicity of drugs. Thus, by determining variance of CYP2D6 using molecular approaches viz., PCR, real-time PCR, DNA micro-array and molecular docking can determine the adverse effects, drug toxicity, bioavailability and therapeutic potential of new drug.

Kalra, Kapil; Jarmal, Garima; Mishra, Neeti

2009-01-01

483

Fisheries management under the Fishery Conservation and Management Act, the Marine Mammal Protection Act, and the Endangered Species Act. Final report  

Microsoft Academic Search

The purpose of this report is to determine what steps might be taken to ensure that fishery management plans (FMPs) developed under the Fishery Conservation and Management Act (FCMA) are ecologically sound and fully consistent with the FCMA and with the Marine Mammal Protection Act (MMPA) and the Endangered Species Act (ESA). The relevant provisions of the three Acts were

Hammond; K. A. G

1980-01-01

484

Enzyme Conversion of Biomass to Fermentable Sugars.  

National Technical Information Service (NTIS)

Saccharification studies indicated the suitability of Trichoderma viride 253 crude enzyme preparation as a promising agent for saccharifying sugarcane baggase hemicellulose, treated alpha -cellulose, and alkali-treated bagasse. Utilization of sugarcane ba...

M. O. Bagby

1983-01-01

485

Ethanologenic enzymes of Zymomonas mobilis. Progress report.  

National Technical Information Service (NTIS)

In this study, we have proposed to investigate the mechanisms which permit the high level expression of the ethanologenic enzymes from Zymomonas mobilis (PDC, ADHI, ADHII). This research is continuing essentially as proposed in the original grant except t...

L. O. Ingram

1990-01-01

486

Ethanologenic Enzymes of Zymomonas Mobilis: Progress Report.  

National Technical Information Service (NTIS)

In this study, we have proposed to investigate the regulatory mechanisms which permit the high level expression of the ethanologenic enzymes from Zymomonas mobilis (PDC, ADHI, ADHII). This research is continuing essentially as proposed in the original gra...

L. O. Ingram

1989-01-01

487

Ethanologenic enzymes of Zymomonas mobilis: Progress report  

SciTech Connect

In this study, we have proposed to investigate the regulatory mechanisms which permit the high level expression of the ethanologenic enzymes from Zymomonas mobilis (PDC, ADHI, ADHII). This research is continuing essentially as proposed in the original grant except that the scope is being expanded to include the glycolytic enzymes which are also highly expressed. Several enzymes which are expressed only at moderate levels are being examined for comparison (tryptophan biosynthesis, acid phosphatase). Studies of highly expressed genes involve enzyme purification and the production of antibodies, investigations of the effects of growth conditions on expression, cloning and characterization of structural genes, construction of hybrid genes, mutation of alcohol dehydrogenases, and investigation of transcriptional and translational regulation. In addition, we are investigating the feasibility of replacing the NAD regeneration systems of other bacteria with an artificial operon containing the Z. mobilis genes (PDC and ADHII) for the production of ethanol, the ''PET'' operon. 30 refs.

Ingram, L.O.

1989-02-01

488

Clostridium perfringens Spore-Lytic Enzymes.  

National Technical Information Service (NTIS)

Enzymes which cause the germination of Clostridium perfringens spores were isolated and characterized. Two were investigated in detail. One was extracted from spores of the same organism. The second was excreted by vegetative cells of C. perfringens. The ...

R. Labbe

1983-01-01

489

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.

Adrio, Jose L.; Demain, Arnold L.

2014-01-01

490

Ribonucleotide reductases: essential enzymes for bacterial life  

PubMed Central

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

Torrents, Eduard

2014-01-01

491

Serum Enzyme Changes after Physical Exertion.  

National Technical Information Service (NTIS)

A study of alterations in selected serum enzymes after physical exertion by young males is reported. Mean serum concentrations of glutamic oxalacetic transaminase (SGOT), lactate dehydrogenase and amylase all increase after the performance of vigorous exe...

I. D. Wilson

1968-01-01

492

Microbial enzymes: tools for biotechnological processes.  

PubMed

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

493

Status of Solid-Phase Enzyme Immunoassays.  

National Technical Information Service (NTIS)

Solid-phase enzyme immunoassays are becoming increasingly popular due to their sensitivity, simplicity, and versatility. The three most common types of these assays (indirect, double-antibody, and competitive binding) have been described and examples give...

G. C. Saunders

1978-01-01

494

An enzyme immunoassay for plasma betamethasone  

SciTech Connect

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

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

1981-03-01

495

A Quantitative Enzyme Study Using Simple Equipment  

NSDL National Science Digital Library

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

Linda B. Cholewiak (Princeton University;); Beth A. D. Nichols (Princeton University;)

1991-01-01

496

Using Enzymes to Make Fish Protein Concentrates.  

National Technical Information Service (NTIS)

Fish protein concentrates having desirable functional properties can be prepared by using selected enzymes to solubilize protein and release lipids. An enzymatic FPC process could make profitable use of some of our underutilized or latent resources. The r...

M. B. Hale

1974-01-01

497

Enzyme mimics: Halogen and chalcogen team up  

NASA Astrophysics Data System (ADS)

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

Metrangolo, Pierangelo; Resnati, Giuseppe

2012-06-01

498

Adenylate Cyclase Toxin (ACT) from Bordetella hinzii: Characterization and Differences from ACT of Bordetella pertussis  

PubMed Central

Bordetella hinzii is a commensal respiratory microorganism in poultry but is increasingly being recognized as an opportunistic pathogen in immunocompromised humans. Although associated with a variety of disease states, practically nothing is known about the mechanisms employed by this bacterium. In this study, we show by DNA sequencing and reverse transcription-PCR that both commensal and clinical strains of B. hinzii possess and transcriptionally express cyaA, the gene encoding adenylate cyclase toxin (ACT) in other pathogenic Bordetella species. By Western blotting, we also found that B. hinzii produces full-length ACT protein in quantities that are comparable to those made by B. pertussis. In contrast to B. pertussis ACT, however, ACT from B. hinzii is less extractable from whole bacteria, nonhemolytic, has a 50-fold reduction in adenylate cyclase activity, and is unable to elevate cyclic AMP levels in host macrophages (nontoxic). The decrease in enzymatic activity is attributable, at least in part, to a decreased binding affinity of B. hinzii ACT for calmodulin, the eukaryotic activator of B. pertussis ACT. In addition, we demonstrate that the lack of intoxication by B. hinzii ACT may be due to the absence of expression of cyaC, the gene encoding the accessory protein required for the acylation of B. pertussis ACT. These results demonstrate the expression of ACT by B. hinzii and represent the first characterization of a potential virulence factor of this organism.

Donato, Gina M.; Hsia, Hung-Lun J.; Green, Candace S.; Hewlett, Erik L.

2005-01-01

499

Nasal absorption of mixtures of fast-acting and long-acting insulins  

PubMed Central

Mixtures of fast-acting and long-acting insulins were administered nasally to anesthetized, hyperglycemic rats in the presence and absence of tetradecyl-?-D-maltoside (TDM). The fast-acting analogs, aspart insulin, lispro insulin, and glulisine insulin, were all rapidly absorbed from the nose when applied individually with 0.125% TDM (Tmax = 15 minutes). One long-acting insulin analog, glargine insulin, was also absorbed from the nose when applied individually in the presence of 0.125% TDM (Tmax = 60 minutes). The other long-acting insulin analog, detemir insulin, was not soluble when formulated with 0.125% TDM. A series of mixtures (1:1) of the three rapid-acting insulins and long-acting glargine insulin were formulated with 0.125% TDM and applied nasally. The pharmacokinetic and pharmacodynamic profiles of the insulin mixtures reflected the additive contributions of both the rapid-acting and the long-acting insulin. These results support the possibility of formulating certain insulin mixtures in tandem to provide nasal insulin products that match the needs of patients with diabetes mellitus better than those currently available.

Pillion, Dennis J.; Fyrberg, Michael D.; Meezan, Elias

2010-01-01

500

A comprehensive analysis of the geranylgeranylglyceryl phosphate synthase enzyme family identifies novel members and reveals mechanisms of substrate specificity and quaternary structure organization.  

PubMed

Geranylgeranylglyceryl phosphate synthase (GGGPS) family enzymes catalyse the formation of an ether bond between glycerol-1-phosphate and polyprenyl diphosphates. They are essential for the biosynthesis of archaeal membrane lipids, but also occur in bacterial species, albeit with unknown physiological function. It has been known that there exist two phylogenetic groups (I and II) of GGGPS family enzymes, but a comprehensive study has been missing. We therefore visualized the variability within the family by applying a sequence similarity network, and biochemically characterized 17 representative GGGPS family enzymes regarding their catalytic activities and substrate specificities. Moreover, we present the first crystal structures of group II archaeal and bacterial enzymes. Our analysis revealed that the previously uncharacterized bacterial enzymes from group II have GGGPS activity like the archaeal enzymes and differ from the bacterial group I enzymes that are heptaprenylglyceryl phosphate synthases. The length of the isoprenoid substrate is determined in group II GGGPS enzymes by 'limiter residues' that are different from those in group I enzymes, as shown by site-directed mutagenesis. Most of the group II enzymes form hexamers. We could disrupt these hexamers to stable and catalytically active dimers by mutating a single amino acid that acts as an 'aromatic anchor'. PMID:24684232

Peterhoff, David; Beer, Barbara; Rajendran, Chitra; Kumpula, Esa-Pekka; Kapetaniou, Evangelia; Guldan, Harald; Wierenga, Rik K; Sterner, Reinhard; Babinger, Patrick

2014-05-01