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)

Protease-like activity which split plasminogen-free fibrin was demonstrated in 2 M KSCN extracts of the lung and spleen of conventional rats. The activity was virtually undetectable in tissue extracts from germ-free rats. The extracts from the conventional rat tissues split fibrin and fibrinogen remarkably at neutral pH, but not casein, when examined using fibrin, fibrinogen-agar and casein-agar plates. The fibrinolytic activity was inhibited by STI and DFP, indicating a serine protease nature. The activity was not inhibited by TLCK, t-AMCHA or dansyl-L-arginine-methylpiperidine amide (a selective synthetic thrombin inhibitor, OM189). It was neither activated nor inhibited by cysteine, KCN or iodoacetic acid. The results obtained indicate that the protease-like activity of the lung and spleen extracted with 2 M KSCN from conventional rats has properties which differ from those of trypsin, plasmin, plasminogen-activator, thrombin, and cathepsin A, B and C.
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PMID:Fibrinolytic activity of lung and spleen extracts observed in conventional but not in germ-free rats. 9 68

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

Protein breakdown in submandibular glands rendered hypertrophic by amputation of the lower incisor teeth in rats was investigated. Reduced protein breakdown was observed in the hypertrophic gland tissues, and was found to be inhibited by 20 mM epsilon-amino-n-caproic acid, an inhibitor of serine protease, and 50 microM leupeptin, an inhibitor of trypsin, plasmin, papain and cathepsin B, but not by 2 mM PMSF (phenylmethylsulfonyl fluoride), an inhibitor of serine protease, 10 microM pepstatin, an inhibitor of cathepsin D and 20 microM antipain, an inhibitor of cathepsin A and B. These results suggest that some serine proteases and leupeptin-sensitive proteases (presumably cathepsin B) participate in protein breakdown in hypertrophic gland tissues, and that hypertrophy of the submandibular glands is closely related to the reduced protein breakdown in these tissues.
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PMID:Protein breakdown in submandibular glands rendered hypertrophic by amputation of lower incisor teeth in rats. 223 Sep 61

Thiol protease inhibitors were found in the cytosol fractions of various rat tissues. An inhibitor, named cytosol thiol protease inhibitor, was purified from rat liver cytosol by acid treatment and column chromatographies on Sephadex G-50, DEAE-Sephadex and Sephadex G-75. The purified inhibitor gave a single protein band on sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. The molecular weight of the inhibitor was found to be 12 400 by gel filtration on Sephadex G-75 and SDS-polyacrylamide gel electrophoresis, and its isoelectric point was found to be 5.04. This inhibitor inhibited rat liver lysosomal cathepsin B, B2, C, H and L and papain, but not cathepsin A or D, trypsin or chymotrypsin. The inhibitor caused noncompetitive inhibition of the hydrolytic activity of cathepsin H on alpha-N-benzoyl-DL-arginine 2-naphthylamide and its Ki value was 4.08 . 10(-8) M. Heat treatment at 80 degrees C for 10 min reduced the activity 40%.
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PMID:Purification and properties of thiol protease inhibitor from rat liver cytosol. 702 26

Lysosomal protective protein/cathepsin A is a serine carboxypeptidase that forms a complex with beta-galactosidase and neuraminidase. The enzyme is synthesized as a 54-kDa precursor/zymogen and processed into a catalytically active 32- and 20-kDa two-chain form. We have expressed in baculovirus-infected insect cells the human one-chain precursor as well as the two separate subunits in order to establish the mode of catalytic activation of the zymogen and the assembly and activation of the two subunits. Infected insect cells synthesize large quantities of the exogenous proteins, which are glycosylated and secreted but not processed. Co-expression of the two subunits results in their assembly into a two-chain form of 34- and 20-kDa with negligible enzymatic activity. Limited proteolysis with trypsin of the 54-kDa precursor and the reconstituted 34- and 20-kDa form gives rise to a fully active 32- and 20-kDa product. These results enabled us to map the sites of proteolytic cleavage needed for full activation of the cathepsin A zymogen. They further indicate that the 34- and 20-kDa form is a transient processing intermediate that is converted into a mature and active enzyme by removal of a 2-kDa "linker" peptide from the COOH terminus of the 34-kDa subunit.
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PMID:Lysosomal protective protein/cathepsin A. Role of the "linker" domain in catalytic activation. 759 59

We identified a chymotrypsin-like activity in the granules of IL-2 lymphokine-activated killer (LAK) cells and a NK cell line (YT) that reacted preferentially with the oligopeptide substrate succinyl-Phe-Leu-Phe-thiobenzyl ester (Suc-Phe-Leu-Phe-SBzl). The enzyme was isolated by detergent extraction of sedimented cytotoxic granules and then by a sequence of sieve, hydrophobic, and anion exchange chromatography. On SDS-PAGE, the protein migrated at 42 kDa in nonreduced form and became two bands (31 and 19 kDa, respectively) after reduction. Amino-terminal sequencing of the reduced protein bands revealed 100% homology with cathepsin A-like protective protein (CAPP), a lysosomal enzyme that expresses serine carboxypeptidase and deamidase activities. The carboxypeptidase activity of lymphocyte CAPP was verified by showing that the protease preferred hydrophobic amino acids in the penultimate position of the C terminus (i.e., cleaved arginine from dansyl-Phe-Leu-Arg). The presence of lymphocyte CAPP in secretory lysosomes was demonstrated by showing that Suc-Phe-Leu-Phe-SBzl activity co-migrated with tryptase and Asp-ase activities on Percoll density gradients and that 95% of the Suc-Phe-Leu-Phe-SBzl activity in granule fractions of cavitated YT cells could be immunoprecipitated with an anti-CAPP antiserum. In addition, calcium ionophore-stimulated YT cells were shown to secrete immunoprecipitable CAPP. As proposed for platelets, lymphocyte CAPP may be secreted to function extracellularly by inactivating bioactive peptides.
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PMID:Dominant chymotrypsin-like esterase activity in human lymphocyte granules is mediated by the serine carboxypeptidase called cathepsin A-like protective protein. 796 38