Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of 1.8 mg/liter (LC50) of mercuric chloride exposure on the activities of alkaline phosphatase, acid phosphatase, glucose-6-phosphatase, amylase, pepsin, trypsin, tripeptidase glycyl-glycine dipeptidase and carnosinase has been examined in Channa punctatus. The three phosphatases have been inhibited in the liver but showed an increase in activity in the intestine and pyloric caeca. Amylase, pepsin and trypsin have also shown a slight increase in activity. There has been no significant alteration in the activites of the peptidases. The results show that mercury inhibits the activites of phosphatases in the liver but has no significant effect on the digestive enzymes within the experimental period of 96 hours.
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PMID:Effect of mercuric chloride on the digestive system of a teleost fish, Channa punctatus. 21 48

Elastolytic enzyme was purified and crystallized from culture fluid of Flavobacterium immotum No. 9-35. The purified enzyme was homogeneous on polyacrylamide gel electrophoresis. The molecular weight was determined by Sephadex G-100 gel filtration to be 13,000. The isoelectric point was between pH 8.3 and 8.9. The optimum pH of the enzyme was 7.2 for elastolytic activity. The purified enzyme showed not only elastolytic activity, but also non-specific proteolytic activity against various other proteins. Milk-clotting activity was also observed. The enzyme did not act on keratin, collagen, or fourteen amino acid esters, including N-benzoyl-L-alanine methyl ester, N-benzoyl-L-arginine ethyl ester, and N-acetyl-L-tyrosine ethyl ester, which were typical substrates of pancreatic elastase [EC 3.4.21.11], trypsin [EC 3.4.21.4], and chymotrypsin [EC 3.4.21.1], respectively. However, the enzyme selectively hydrolyzed elastin when both elastin and albumin were present in the reaction mixture. The enzyme was inhibited by o-phenanthroline and various heavy metals such as cadmium, lead, zinc, and mercury. Various inhibitors, such as diisopropyl phosphofluoridate, tosyl-L-lysine chloromethyl ketone, tosyl-L-phenylalanine chloromethyl ketone, trypsin inhibitor, iodoacetamide, etc., had no effect on the elastolytic activity.
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PMID:Purification and properties of elastolytic enzyme from Flavobacterium immotum. 23 95

1-Acyl-2-(7-(4-azido-2-nitrophenoxy)-[1-14C]heptanoly)-sn-glycero-3-phosphocholine was synthesized in order to study the lipid-binding site of the phosphatidylcholine exchange protein from bovine liver. Photosensitive phosphatidylcholine was incorporated into the protein by incubation with vesicles of this phosphatidylcholine derivative. The lipid-protein complex was separated from the vesicles by chromatography on Biogel A-0.5m. Photolysis of the complex by irradiation with light of a high pressure mercury lamp at a wavelength above 340 nm generated the highly reactive nitrene. Sodium dodecyl sulfate gel electrophoresis of the photolysed complex indicated that 30% of the endogenous 14C-labeled phosphatidylcholine was covalently linked to the protein. Peptides were isolated after digestion of the photolysed complex with protease from Staphylococcus aureus and trypsin. It was determined that the 2-acyl chain of the phosphatidylcholine molecule was linked to the peptide segment -Gly-Ser-Lys-Val-Phe-Met-Tyr-Tyr-. This segment was part of a protease peptide of about 65 residues of which the sequence was determined by Edman degradation for the first 38 residues. This peptide contains a cluster of apolar residues -Val-Phe-Met-Tyr-Tyr-Phe with an extremely high hydrophobicity index and with a predicted beta-sheet conformation. It is concluded that this hydrophobic cluster forms part of the binding site.
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PMID:Determination of the hydrophobic binding site of phosphatidylcholine exchange protein with photosensitive phosphatidylcholine. 49 8

Peripheral blood lymphocytes of phenyl mercury acetate exposed persons and a control population of the same age were cultured for 48 h. In both populations 100 metaphases were trypsin-banded and caryotyped. The relative position of the metaphase chromosomes was studied by means of centromere--centromere distances (delta2) and centromere--metaphase centre distances (d2) obtained by computer-aided mathematical transformation of the individual metaphase coordinates. By comparing both investigated cell populations we mainly observed that the chromosome combinations which statistically differ in mercury-exposed workers from the controls show an increase of centromere-centromere distances after mercury exposure. From the data we may suggest that phenyl mercury acetate influences at first the position of particular chromosomes; especially D-group chromosomes which are involved in nucleolus organisation. This may be due to a greater density of SH-wearing molecules in that region or to a possible inhibition of specific enzymes regulating the nucleolar activity. The exposure level is however too low to allow definite conclusions in this respect.
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PMID:Chromosome distribution studies in phenyl mercury acetate exposed subjects and in age-related controls. 67 33

The effect of trace metals on plasma alpha1-antitrypsin was studied in vitro by adding known concentrations of trace metals, either alone or in combination, to plasma. Cadmium was the only trace metal that reduced the concentration of alpha1-antitrypsin and depressed the trypsin inhibitory capacity. No such effects were found with divalent lead, mercury, nickel, iron, and zinc ions. The present study appears to offer a plausible explanation for the emphysema that occurs in industrial workers exposed to cadmium.
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PMID:Influence of cadmium and other trace metals on human alpha1-antitrypsin: an in vitro study. 108 68

A metalloproteinase with a specificity for gelatin was isolated from serum-free medium of cultures of rheumatoid synovial fluid. The enzyme showed all the properties of a leukocyte gelatinase. In addition to gelatin this proteinase cleaved the synthetic substrate dinitrophenyl-Pro-Gln-Gly-Ile-Ala-Gly-Gln-D-Arg (Dnp-peptide) rapidly, while casein was a much poorer substrate. This proteinase showed no enzymatic activity against collagen type I, was secreted in a latent form and could be activated by trypsin or organomercurial compounds, such as mersalylic acid or 4-aminophenyl-mercury acetate. The latent enzyme had an apparent molecular mass of 130,000-150,000 estimated by gel filtration or 97,000 by electrophoresis on polyacrylamide gel containing sodium dodecyl sulphate. When analysed by immunoblotting the enzyme was recognized by antibodies raised against human polymorphonuclear leukocyte gelatinase. Although we found synovial fibroblasts to be largely present in the cell cultures we could not detect any fibroblast gelatinase activity.
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PMID:Characterization of a gelatinase from human rheumatoid synovial fluid cells. 165 60

We discovered an enzyme in human platelets that deamidates substance P and other tachykinins. Because an amidated carboxyl terminus is important for biological activity, we purified and characterized this deamidase. The enzyme, released from human platelets by thrombin, was purified to homogeneity by ammonium sulfate precipitation, followed by chromatography on an octyl-Sepharose column and chromatofocusing on PBE 94. The purified enzyme exhibits esterase, peptidase, and deamidase activities. The peptidase activity (with furylacryloyl-Phe-Phe) is optimal at pH 5.0 while the esterase (benzoyl-tyrosine ethyl ester) and deamidase (D-Ala2-Leu5-enkephalinamide) activities are optimal at pH 7.0. With biologically important peptides, the enzyme acts both as a deamidase (substance P, neurokinin A, and eledoisin) and a carboxy-peptidase (with bradykinin, angiotensin I, substance P-free acid, oxytocin-free acid) at neutrality, although the carboxypeptidase action is faster at pH 5.5. Enkephalins, released upon deamidation of enkephalinamides, were not cleaved. Gly9-NH2 of oxytocin was released without deamidation. Peptides with a penultimate Arg residue were not hydrolyzed. Some properties of the deamidase are similar to those reported for cathepsin A. The deamidase is inhibited by diisopropylfluorophosphate, inhibitors of chymotrypsin-type enzymes, and mercury compounds while other inhibitors of catheptic enzymes, trypsin-like enzymes, and metalloproteases were ineffective. In gel filtration, the native enzyme has an Mr = 94,000 while in non-reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis the Mr = 52,000 indicating it exists as a dimer. After reduction, deamidase dissociates into two chains of Mr = 33,000 and 21,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. [3H]diisopropylfluorophosphate labeled the active site serine in the Mr = 33,000 chain. The first 25 amino acids of both chains were sequenced. They are identical with the sequences of the two chains of lysosomal "protective protein" which, in turn, has sequence similarity to the KEX1 gene product and carboxypeptidase Y of yeast. This protective protein complexes with beta-galactosidase and neuraminidase in lysosomes and is vitally important in maintaining their activity and stability. A defect in this protein is the cause of galactosialidosis, a severe genetic disorder. The ability of physiological stimuli (e.g. thrombin or collagen) to release the deamidase from platelets indicates that it may also be involved in the local metabolism of bioactive peptides.
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PMID:A peptidase in human platelets that deamidates tachykinins. Probable identity with the lysosomal "protective protein". 169 76

Vascular mechanisms play an important but controversial role in the pathogenesis of acute pancreatitis. In experimental animals, injection of wax, powder, air, mercury, and microspheres into the pancreatic artery causes pancreatitis by end artery occlusion with resulting cellular infarction. Larger microspheres do not cause pancreatitis because collateral blood flow is preserved. Clinical evidence, such as microthrombi and atheromatous emboli in the pancreatic artery of patients with pancreatitis, supports pancreatic infarction as an etiologic agent. Experimental and clinical studies have suggested that pancreatic ischemia may also cause pancreatitis, but these studies have not been conclusive. We have compared five hours of total occlusion of the pancreaticoduodenal artery along with four hours of reperfusion to bile injection into the pancreatic duct as causes of pancreatitis. Bile injection caused a significant increase in serum amylase, activation of trypsin in pancreatic exudate, and histologic evidence of necrotizing pancreatitis. Pancreatic blood flow decreased as pancreatitis developed. Ischemia for five hours did not cause a significant increase in serum amylase or activation of trypsin in pancreatic exudate. Only edema was seen histologically, but there was no necrosis. Pancreatic blood flow increased with reperfusion. We believe ischemia aggravates, but does not initiate pancreatitis. Ischemia does not induce inflammation and necrosis in the pancreas, although infarction does.
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PMID:Mechanisms of acute pancreatitis. Vascular etiology. 174 44

Structural variants of mercury reductase containing the N-terminal domain, which is easily cleaved by trypsin, have been found in Gram-positive bacteria with a low genomic G + C content (Bacillus, Staphylococcus and, possibly, some other genera). Mercury reductases without the N-terminal domain and relatively resistant to limited proteolysis are typical for Gram-positive bacteria with a high genomic G + C content (Arthrobacter, Citreobacterium, Micrococcus, Mycobacterium, Rhodococcus). Both types of mercury reductase genes may be located on plasmids.
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PMID:Occurrence of two structural types of mercury reductases among gram-positive bacteria. 204 Apr 34

Gentamicin nephrotoxicity in vivo has a delayed onset. Our assessment of gentamicin-induced cell death in vitro, by measuring the release of cytosolic lactate dehydrogenase (LDH), indicated a prolonged onset as well. A recent study, which showed that gentamicin caused an abrupt increase in the concentration of cytosolic free calcium ([Ca2+]i) in a trypsin-harvested kidney cell line, suggested that immediate changes in calcium homeostasis may initiate the pathogenesis of gentamicin nephrotoxicity. To study the immediate effect of gentamicin on [Ca2+]i, gentamicin was perfused for 1 hr over primary monolayer cultures of renal cortical epithelial cells, and suspensions of trypsin-harvested renal cells (from primary cultures and a cell line) were treated with gentamicin for 30 min. [Ca2+]i was determined using the fluorescent probe fura-2. Positive controls (ionomycin and mercury) reliably increased [Ca2+]i in each experimental model, but no increase in [Ca2+]i was observed with gentamicin. Because enzyme release data indicated that significant cytotoxicity did not occur until 48 hr of exposure to 2 mM gentamicin, primary cultures were exposed to gentamicin (1-2 mM) for 24-48 hr and [Ca2+]i was measured. No gentamicin-induced increase in [Ca2+]i was observed in these longer exposures, whether or not significant LDH release occurred. These results do not support a role for elevated [Ca2+]i in the cytotoxicity of gentamicin in cultured kidney cells, either immediately after exposure or following prolonged exposures.
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PMID:Lack of changes in cytosolic ionized calcium in primary cultures of rat kidney cortical cells exposed to cytotoxic concentrations of gentamicin. 225 82


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