Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The alkalophile NADH dehydrogenase (NADH: 2,6-dichlorophenolindophenol oxidoreductase) [EC 1.6.99.3] consists of two identical subunits of 65 kDa, and each subunit contains the catalytic and liposome-binding regions. On treatment with trypsin, the polypeptide exhibiting the liposome-binding property in one of the subunits was digested to form an enzymatically active hetero-dimer (40 and 65 kDa), and then the polypeptide in the other subunit was digested to form an active homo-dimer (40 and 40 kDa). The hetero-dimer bound to liposomes, but the homo-dimer did not. Kinetic analysis showed that removal of one or two of the polypeptides in the enzyme slightly affects its kinetic parameters. For all the enzyme species, NAD inhibited competitively with respect to NADH and non-competitively with respect to 2,6-dichlorophenolindophenol. The partially determined amino acid sequence of this alkalophile enzyme suggested that (i) a long random-coiled peptide (58 amino acid residues) or a portion of the peptide is located between the polypeptides with liposome-binding and catalytic properties, (ii) the polypeptide exhibiting liposome-binding property is in the amino terminal region of the enzyme, (iii) the amino acid sequences around the subtilisin and trypsin cleavage sites of the peptide are hydrophilic and on the surface of the protein molecule and therefore are susceptible to digestion, and (iv) the FAD-binding site is located near the amino terminal region of the catalytic region.
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PMID:Tryptic digestion of NADH dehydrogenase from alkalophilic Bacillus. 276 20

Assimilatory nitrate reductase from Chlorella is a homotetramer which contains one of each of the prosthetic groups FAD, heme, and molybdenum per subunit. Besides the reduction of nitrate by NADH, nitrate reductase also catalyzes the partial activities NADH:cytochrome c reductase, NADH:ferricyanide reductase, and reduced methyl viologen:nitrate reductase. Incubation of native nitrate reductase with either trypsin, Staphylococcus aureus V8 protease, or a natural inactivator protease from corn results in a loss of NADH:nitrate reductase and NADH:cytochrome c reductase activities but no loss of reduced methyl viologen:nitrate reductase activity. Incubation of nitrate reductase with V8 protease or corn inactivator protease resulted in two different products, each of which retained a different partial activity. Reduced methyl viologen:nitrate reductase activity was associated with a homotetrameric fragment of about 260 kDa which contained heme and molybdenum but no FAD. The molecular mass of native nitrate reductase determined under the same conditions was 375 kDa. NADH:ferricyanide reductase activity was associated with a monomeric species of approximately 30 kDa which contained FAD and the NADH-binding site. These results are consistent with a structure-function model of nitrate reductase which has the following features: FAD/NADH-binding domains exposed on the surface of the molecule, a protease-sensitive hinge region which connects the nitrate-reducing and NADH dehydrogenase moieties, and the quaternary structure maintained via association sites on the heme/molybdenum domain.
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PMID:Functional domains of assimilatory NADH:nitrate reductase from Chlorella. 301 63

Oxidative phosphorylation and Ca2+-transport functions of liver mitochondria were normalized in rats with alloxane diabetes after peroral administration of phytoecdisteroids - ecdisterone and turkesterone (5 mg/kg) or nerobol (10 mg/kg) within 15 days. These drugs normalized the activity of NADH dehydrogenase and succinate dehydrogenase in respiratory chain of mitochondria, increased distinctly stability of the enzymes to the effect of such factors as heating, effect of phospholipase A2 or trypsin.
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PMID:[Comparative study of the effect of ecdysterone, turkesterone and nerobol on the function of rat liver mitochondria in experimental diabetes]. 377 12

The NADH oxidase of Amphibacillus xylanus shows high NADH-peroxide reductase activity for hydrogen peroxide and alkyl hydroperoxides in the presence of a 22-kDa disulfide-containing protein component (Y. Niimura, L. B. Poole, and V. Massey, J. Biol.Chem. 270, 25645-25650, 1995). It was found that the membrane-bound NADH dehydrogenase of an alkaliphilic Bacillus (YN-1) involved in the respiratory chain also exhibits reductase activity for hydrogen peroxide and cumene hydroperoxide in the presence of the 22-kDa component from Amphibacillus xylanus. Vmax values for these substrates were as high as those of the NADH oxidase of A. xylanus. Although the 38-kDa protein produced by trypsin treatment of NADH dehydrogenase retains NADH dehydrogenase activity, it exhibited no peroxide reductase activity in the presence of the 22-kDa component from A. xylanus. The NADH dehydrogenase of YN-1 might not only catalyze electron flow from NADH to the respiratory chain, but also function for scavenging peroxide.
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PMID:Peroxide reductase activity of NADH dehydrogenase of an alkaliphilic Bacillus in the presence of a 22-kDa protein component from Amphibacillus xylanus. 964 49

We have investigated the topologies of Ndh (a plastid complex with NADH dehydrogenase activity) and its NDH-F subunit in thylakoids by trypsin and proteinase V8 digestion of both intact and Triton X-100-permeabilized barley thylakoids and identification of the products with antibodies against specific sequences of the NDH-A, NDH-K and NDH-F subunits. Antibody binding and protection against proteinases were also assayed. The analysis of the digestion products of NDH-F by immunodetection and matrix-assisted laser-desorption ionization-time-of-flight allowed us to propose its membrane topology and to compare it with bioinformatic predictions and with that of the homologous subunit (ND5/NuoL/NQO12) of the respiratory complex I. Results indicate that the thylakoid Ndh complex may have an L-shaped structure, similar to that of respiratory complex I, with the hydrophilic arm orientated towards the stroma and the hydrophobic arm inserted into the thylakoid. NDH-A and NDH-K may be located at the bridge between the two arms. Similar to ND5/NuoL/NQO12 of complex I, NDH-F must be distally located in the hydrophobic arm. NDH-F would include up to 15 transmembrane helices and 14 hydrophilic regions. A conserved His-349 in the X transmembrane helix could be involved in H+ pumping. The conserved Thr-181 NDH-F, whose probable phosphorylation increases the activity of the Ndh complex, is located within the hydrophilic region between the V and VI transmembrane helices.
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PMID:Topology of the plastid Ndh complex and its NDH-F subunit in thylakoid membranes. 1512 88

Mitochondria isolated from potato (Solanum tuberosum L.) tuber were investigated for the presence of a nicotinamide nucleotide transhydrogenase activity. Submitochondrial particles derived from these mitochondria by sonication catalyzed a reduction of NAD(+) or 3-acetylpyridine-NAD(+) by NADPH, which showed a maximum of about 50 to 150 nanomoles/minute.milligram protein at pH 5 to 6. The K(m) values for 3-acetylpyridine-NAD(+) and NADPH were about 24 and 55 micromolar, respectively. Intact mitochondria showed a negligible activity in the absence of detergents. However, in the presence of detergents the specific activity approached about 30% of that seen with submitochondrial particles. The potato mitochondria transhydrogenase activity was sensitive to trypsin and phenylarsine oxide, both agents that are known to inhibit the mammalian transhydrogenase. Antibodies raised against rat liver transhydrogenase crossreacted with two peptides in potato tuber mitochondrial membranes with a molecular mass of 100 to 115 kilodaltons. The observed transhydrogenase activities may be due to an unspecific activity of dehydrogenases and/or to a genuine transhydrogenase. The activity contributions by NADH dehydrogenases and transhydrogenase to the total transhydrogenase activity were investigated by determining their relative sensitivities to trypsin. It is concluded that, at high or neutral pH, the observed transhydrogenase activity in potato tuber submitochondrial particles is due to the presence of a genuine and specific high molecular weight transhydrogenase. At low pH an unspecific reaction of an NADH dehydrogenase with NADPH contributes to the total trans-hydrogenase activity.
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PMID:On the presence of a nicotinamide nucleotide transhydrogenase in mitochondria from potato tuber. 1666 99

Glyoxysomal membranes from germinating castor bean (Ricinus communis L. cv Hale) endosperm contain an NADH dehydrogenase. This enzyme can utilize extraorganellar ascorbate free-radical as a substrate and can oxidize NADH at a rate which can support intraglyoxysomal demand for NAD(+). NADH:ascorbate free-radical reductase was found to be membrane-associated, and the activity remained in the membrane fraction after lysis of glyoxysomes by osmotic shock, followed by pelleting of the membranes. In whole glyoxysomes, NADH:ascorbate free-radical reductase, like NADH:ferricyanide reductase and unlike NADH:cytochrome c reductase, was insensitive to trypsin and was not inactivated by Triton X-100 detergent. These results suggest that ascorbate free-radical is reduced by the same component which reduces ferricyanide in the glyoxysomal membrane redox system. NADH:ascorbate free-radical reductase comigrated with NADH:ferricyanide and cytochrome c reductases when glyoxy-somal membranes were solubilized with detergent and subjected to rate-zonal centrifugation. The results suggest that ascorbate free-radical, when reduced to ascorbate by membrane redox system, could serve as a link between glyoxysomal metabolism and other cellular activities.
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PMID:Ascorbate free-radical reduction by glyoxysomal membranes. 1666 45

Growth hormone (GH) transgenic amago salmon (Oncorhynchus masou) were generated with a construct containing the sockeye salmon GH1 gene fused to the metallothionein-B (MT-B) promoter from the same species. This transgene directed significant growth enhancement with transgenic fish reaching approximately four to five times greater weight than control salmon in F(2) and F(3) generations. This drastic growth enhancement by GH transgene is well known in fish species compared with mammals, however, such fish can show morphological abnormalities and physiological disorders like other GH transgenic animals. GH is known to have many acute effects, but currently there are no data describing the chronic effects of over-expression of GH on various hepatic genes in GH transgenic fish. Hepatic gene expression is anticipated to play very important roles in many physiological functions and growth performance of transgenic and control salmon. To examine these effects, we performed subtractive hybridization (using cDNA generated from liver RNA) in both directions to identify genes both increased and decreased in transgenic salmon relative to controls (576 clones were isolated and sequenced in total). Heme oxygenase, vitelline envelope protein, Acyl-coA binding protein, NADH dehydrogenase, mannose binding lectin-associated serine protease, hemopexin-like protein, leucyte-derived chemotaxin2 (LECT2), and many other genes were obtained in higher clone frequencies suggesting enhanced expression. In contrast, complement C3-1, lectin, rabin, alcohol dehydrogenase, Tc1-like transposase, Delta6-desaturase, and pentraxin genes were obtained in lower frequencies. Microarray analysis was also performed to obtain quantitative expression data for these subtracted cDNA clones. Analysis of fish across seasons was also conducted using both F(2) and F(3) salmon. Results of the microarray data essentially corresponded with those of the subtraction data when both F(2) and F(3) fish were completely immature, but the expression pattern was changed when fish approached maturation. Genes showing enhanced expression in GH transgenic fish in F(2) and F(3) by array analysis were vitelline envelope protein, hemopexin-like protein, heme-oxygenase, inter alpha-trypsin inhibitor, LECT2, GTP cyclohydrolase I feedback regulatory protein (GFRP), and bikunin. Reduced expression genes were lectin, Delta6-desaturase, apolipoprotein, and pentraxin. In particular, lectin was found to be highly suppressed in all F(2) and immature F(3) salmon. Further, serum lysozyme activity, one of innate immunity, was significantly (p<0.05) decreased in both F(2) and F(3) GH transgenic fish. These results indicate that the GH transgene fish had altered hepatic gene expression relating to iron-metabolism, innate immunity, reproduction, and growth.
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PMID:Changes in hepatic gene expression related to innate immunity, growth and iron metabolism in GH-transgenic amago salmon (Oncorhynchus masou) by cDNA subtraction and microarray analysis, and serum lysozyme activity. 1722 41

The role of insect saliva in the first contact between an insect and a plant is crucial during feeding. Some elicitors, particularly in insect regurgitants, have been identified as inducing plant defence reactions. Here, we focused on the salivary proteome of the green peach aphid, Myzus persicae. Proteins were either directly in-solution digested or were separated by 2D SDS-PAGE before trypsin digestion. Resulting peptides were then identified by mass spectrometry coupled with database investigations. A homemade database was constituted of expressed sequence tags from the pea aphid Acyrtosiphon pisum and M. persicae. The databases were used to identify proteins related to M. persicae with a nonsequenced genome. This procedure enabled us to discover glucose oxidase, glucose dehydrogenase, NADH dehydrogenase, alpha-glucosidase and alpha-amylase in M. persicae saliva. The presence of these enzymes is discussed in terms of plant-aphid interactions.
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PMID:Identification of aphid salivary proteins: a proteomic investigation of Myzus persicae. 1835 5

The diamondback moth, Plutella xylostella (L.), is a worldwide pest of cruciferous crops and can rapidly develop resistance to many chemical insecticides. Although insecticidal crystal proteins (i.e., Cry and Cyt toxins) derived from Bacillus thuringiensis (Bt) have been useful alternatives to chemical insecticides for the control of P. xylostella, resistance to Bt in field populations of P. xylostella has already been reported. A better understanding of the resistance mechanisms to Bt should be valuable in delaying resistance development. In this study, the mechanisms underlying P. xylostella resistance to Bt Cry1Ac toxin were investigated using two-dimensional differential in-gel electrophoresis (2D-DIGE) and ligand blotting for the first time. Comparative analyses of the constitutive expression of midgut proteins in Cry1Ac-susceptible and -resistant P. xylostella larvae revealed 31 differentially expressed proteins, 21 of which were identified by mass spectrometry. Of these identified proteins, the following fell into diverse eukaryotic orthologous group (KOG) subcategories may be involved in Cry1Ac resistance in P. xylostella: ATP-binding cassette (ABC) transporter subfamily G member 4 (ABCG4), trypsin, heat shock protein 70 (HSP70), vacuolar H(+)-ATPase, actin, glycosylphosphatidylinositol anchor attachment 1 protein (GAA1) and solute carrier family 30 member 1 (SLC30A1). Additionally, ligand blotting identified the following midgut proteins as Cry1Ac-binding proteins in Cry1Ac-susceptible P. xylostella larvae: ABC transporter subfamily C member 1 (ABCC1), solute carrier family 36 member 1 (SLC36A1), NADH dehydrogenase iron-sulfur protein 3 (NDUFS3), prohibitin and Rap1 GTPase-activating protein 1. Collectively, these proteomic results increase our understanding of the molecular resistance mechanisms to Bt Cry1Ac toxin in P. xylostella and also demonstrate that resistance to Bt Cry1Ac toxin is complex and multifaceted.
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PMID:Proteomics-based identification of midgut proteins correlated with Cry1Ac resistance in Plutella xylostella (L.). 2752 21


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