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 plasma esterase inhibitors alpha2-macroglobulin, alpha1-antitrypsin, C1-inhibitor, antithrombin-heparin cofactor, and, as previously described, soybean trypsin inhibitor (Kunitz) and diisopropylphosphorofluoridate (9) enhance the response of guinea pig macrophages to migration inhibitory factor. To obtain this effect, macrophages are incubated with inhibitors prior to assay. The data suggest that (a) the enhancement of migration inhibitory factor response is due to the inhibition of esterases associated with the macrophage through a distinct active site on the inhibitors, and (b) that the active sites of antithrombin-heparin cofactor and soybean trypsin inhibitor, which interact with the macrophage enzymes, are different from the active sites of these inhibitors which interact with thrombin and trypsin respectively. Chemical modification of the active site of antithrombin-heparin cofactor for thrombin and of soybean trypsin inhibitor for trypsin does not affect their capacity to enhance the migration inhibitory factor response. From studies with thrombin, it was known that antithrombin-heparin cofactor has a heparin binding site. Addition of heparin was found to prevent the migration inhibitory factor-enhancing effect of antithrombin-heparin cofactor. The present results suggest that plasma esterase inhibitors may play a regulatory role in the response of macrophages to mediators of cellular immunity.
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PMID:Enhancement of migration inhibitory factor activity by plasma esterase inhibitors. 109 92

Hemolymph of the marine mollusc, Aplysia californica, contains four large particles: acetylcholinesterase, hemocyanin, a hemagglutinin, and a structure tentatively identified as erythrocurorin. We purified the acetylcholinesterase 20-fold by differential centrifugation and filtration through a column of 4% agarose. The freshly isolated esterase complex was found to have a sedimentation coefficient of 69, but the negatively stained enzyme lacked a definite structure in the electron microscope, and appeared as irregular aggregates of a 60 A subunit. The complex was unstable below pH 5 or during storage at 7 degrees. Under these conditions, enzymatic activity remained essentially unchanged. Treatment of the purified enzyme with trichloroacetic acid, organic solvents, and sodium dodecyl sulfate broke the complex down into two major subunits with molecular weights of about 70,000. Exposure of the enzyme to [3H]diisopropylfluorophosphate resulted in the labeling of one of these subunits. Although similar in specificity, the cholinesterase of the blood differed from the enzyme in Aplysia nervous tissue, which is associated with membrane. Treatment with sodium deoxycholate activated the membrane-associated enzyme but inhibited slightly that of the hemolymph; tyrocidine inhibited the hemolymph enzyme but not the enzyme of nervous tissue; and mild digestion with trypsin released the membrane-bound enzyme in an active, soluble form, but inactivated the enzyme of hemolymph. The other particulates of Aplysia hemolymph were partially characterized. Aplysia hemocyanin was similar in structure to other molluscan hemocyanins. When negatively stained, the unit particle appeared to be a disc with a diameter of 280 A and a width of 45 A. These discs were stacked to form long cylindrical arrays. The purified hemocyanin was found to contain 0.26% copper (dry weight). Using differential centrifugation and gel filtration we also obtained a 9-fold purification of Aplysia hemagglutinin. This particle was 120 A in diameter with a dark staining central core of 40 A consisting of 6 subunits. The particle tentatively identified as erythrocurorin appeared as a structure 200 A in diameter consisting of 5 V-shaped subunits.
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PMID:Isolation and characterization of acetylcholinesterase and other particulate proteins in the hemolymph of Aplysia californica. 111 86

N-Butyrylimidazole has been found to be a potent inhibitor of purified bovine thrombin. The rate and extent of inhibition of thrombin by N-butyrylimidazole could be reduced by the presence of benzamidine, a competitive inhibitor, or by the ester substrate, p-tosyl-L-arginine methyl ester. Spectral studies of the reaction of N-butyrylimidazole with thrombin demonstrated the modification of approximately 1 mol of tyrosine/mol of enzyme at maximum inhibition. In addition to the reaction with tyrosine, N-butyrylimidazole also appears to react with a residue at the "active site" as judged by a decrease in the number of active sites available in the modified enzyme for titration with p-nitrophenyl-p'-guanidinobenzoate. The time course of ester hydrolysis by butyrylated thrombin showed a distinct lag phase suggesting partial reactivation of the enzyme under assay conditions. Partial reactivation of the modified enzyme also occurred spontaneously upon standing in 0.5 M NaCl but was much faster in presence of imidazole (0.03 M, pH 7.6). It is suggested that, in addition to reaction with tyrosine, there is a reaction of N-butyrylimidazole with either the histidine and/or serine residue at the active site of thrombin resulting in a derivative unstable under esterase assay conditions such as that described for the reaciton of N-acetylimidazole with trypsin (L. L. Houston and K. A. Walsh (1970), Biochemistry 9, 156).
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PMID:The reaction of bovine thrombin with N-butyrylimidazole. Two different reactions resulting in the inhibition of catalytic activity. 116 84

The N and O substitution in wall peptidoglycan from Lactobacillus fermentum was studied in relation to growth phase, as well as the lytic activities and the effect of trypsin on them. The N-nonsubstituted sites were determined by dinitrophenylation techniques. The results indicate that an extensive substitution at the O groups takes place as cells go into the stationary growth phase, concomitant with a decrease in their lysozyme sensitivity. N-nonsubstituted residues, mainly glucosamine, occurred in both exponential-phase and stationary-phase walls but not in the corresponding peptidoglycans. Small amounts of N-nonsubstituted muramic acid were detected in walls and peptidoglycan from cells in the stationary growth phase only. N acetylation of isolated walls did not increase their lysozyme sensitivity but rather decreased it. Autolysis of walls was completely inhibited by the chemical modifications used. Trypsin stimulates the lysozyme sensitivity of native walls but has no effect on walls that had been O deacetylated and N acetylated. It is suggested that the effect of trypsin is due to its action as an esterase removing the O acetylation in lysozyme-resistant walls.
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PMID:Lysis of modified walls from Lactobacillus fermentum. 117 37

Specific trypsin substrates (esters, anilides, amides, peptides) were shown to accelerate deacetylation of monoacetylated trypsin. The amidase activity of monoacetyl-, monopropyonyl-, and tetraformyl-trypsin was not manifested if the amidase activity of native enzyme was suppressed in these preparations by the ester substrates (benzoylarginine ethyl ester or p-nitrophenyl acetate). Therefore the differences in the residual amidase and esterase activities of these acylated trypsin preparations found earlier did not contradict the universality of the acylenzyme mechanism. These differences are due to the strong deacylating effect of specific substrate in its complex with the enzyme modified with nonspecific acyl residue. The latter fact is suggested to be an experimental confirmation of the "induced fit" hypothesis.
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PMID:[The nature of differences in amidase and esterase activities of some acyltrypsins]. 120 61

In 116 patients with acute and chronic pyelonephritis and in 66 healthy persons the total proteolytic, trypsin-like, catheptic, BAEE-esterase activities and the content of trypsin inhibitor were determined in blood serum and kidney tissue. The total proteolytic and catheptic activities were distinctly increased in blood serum and, especially, in kidney tissue under acute pyelonephritis. In chronic pyelonephritis the activity of cathepsins was decreased in blood serum. The trypsin-like activity tended to decrease both in blood serum and kidney. The BAEE-esterase activity was increased in kidney, particularly in acute pyelonephritis, but in blood serum it was decreased. The inhibitor of trypsin was not found in kidney; in blood serum its content was slightly increased in acute pyelonephritis but there were only slight alterations in the chronic disease.
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PMID:[Activity of proteolytic enzymes and trypsin inhibitor in blood serum and kidney in pyelonephritis]. 121 70

A comparative enzyme analysis was performed on 3 pancreatic extracts generally used for dermal-epidermal separation, namely, crude trypsin (Difco), crude trypsin (Sigma) and pancreatin. A fourth pancreatic extract, crude lipase, was subjected to a corresponding analysis. The 4 extracts were assayed for activities of: protease (total), trypsin, chymotrypsin, carboxypeptidase-A, amylase, elastase, lipase, esterase, arylesterase and ribonuclease. Relative activities of the different proteolytic enzymes were individualized by utilizing specific inhibitors. Insignificant differences were observed between the enzyme activities of crude trypsin (Difco) and pancreatin. Crude lipase displayed similar enzyme activities as these two extracts in addition to high lipolytic, esterolytic and arylesterolytic activities. Crude trypsin (Sigma) exhibited higher tryptic and chymotryptic activities than the other extracts but lacked all further enzyme activities. Epidermal separation was performed using similar incubation conditions for each extract and skin from the same donor. Ultrastructural examination of the detached epidermis revealed that a more effective separation could be achieved by crude lipase.
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PMID:An analysis of pancreatic enzymes used in epidermal separation. 123 61

The interaction of bovine thrombin [EC 3.4.21.5] with synthetic substrates and products was studied. The enzyme was purified from Parke-Davis topical thrombin. The purification process afforded some preparations with different clottin specific activities but with similar esterase specific activities. The preparation having highest clotting specific activity and that having lowest clotting activity were tentatively named thrombin-C and thrombin-E, respectively. Kinetic parameters for the hydrolysis of synthetic substrates and normality titrants were determined on the basis of active enzyme quantity, which was assayed by means of a fluorometric normality titrant. It was shown that thrombin-E was acylated by the substrates more slowly than thrombin-C, while deacylation proceeded at similar rates in the two preparations. The results were also compared with those obtained with bovine trypsin [EC 3.4.21.4]. The acylation rates of both thrombin preparations were markedly lower than that of trypsin, while the deacylation rates of the former were only slightly lower than that of the latter. The effects of various product-type inhibitors, such as benzyloxycarbonyl-, benzoyl-, and tosyl-L-arginine, were also examined. Thrombin was affected by these inhibitors not competitively, though trypsin was inhibited competitively.
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PMID:Comparison of the catalytic properties of thrombin and trypsin by kinetic analysis on the basis of active enzyme concentration. 124 85

The effect of penicillin, tetracycline, aminoglucozide antibiotics and streptomycin on BAEE-esterase activity of trypsin was studied. It was found that benzylpenicillin in amounts of 50, 100 and 300 mg, ampicillin in an amount of 25 mg, methicillin in an amount of 12 mg and tetracycline in an amount of 2.5 mg as calculated per 1 mg of trypsin had no effect in vitro on the esterase activity of the enzyme. Neomycin, kanamycin and streptomycin in amounts of 5, 10, 100 or 300 mg per 1 mg of trypsin catalyzed splitting of BAEE by trypsin. When the antibiotics were added to the bile, its esterase activity increased. Preliminary intramuscular administration of trypsin and kanamycin to the rats had no effect on the ampicillin levels in the blood serum and brain and did not affect the permeability of the hemato-encephalic barrier as compared to the use of trypsin alone.
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PMID:[Antibiotic interaction with proteolytic enzymes]. 127 57

The relationship between serum and tumour cell surface proteolytic enzymes and the development of muscle breakdown in cancer cachexia has been studied in a murine model of the condition (MAC16). The surface of the MAC16 tumour cells carried a proteolytic enzyme referred to as guanidinobenzoatase (GB). Serum from mice also contained an enzyme (referred to as MSE) which cleaved the trypsin inhibitor 4-methylumbelliferyl-p-guanidinobenzoate as a true substrate, but there was no relationship with weight loss or the presence or absence of tumour and the level of this serum enzyme. Polyunsaturated fatty acids (PUFAs) were shown to be inhibitors of MSE at microM concentrations and one PUFA, eicosapentaenoic acid (EPA) was found to be a non-competitive inhibitor of both MSE and GB. The effect of EPA was specific since other proteolytic enzymes, trypsin, esterase and tissue plasminogen activator were unaffected by concentrations inhibiting GB and MSE. MSE and GB are two different enzymes which possess some common properties. However, GB is likely to be significant for tumour development since MSE is also found in normal mouse serum.
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PMID:Observations on the inhibition of serum and cell surface enzymes by eicosapentaenoic acid. 128 67


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