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 extracellular and cell-associated hydrolase profiles of a number of Pseudomonas fluorescens strains were examined with the Analytab API ZYM system. Esterase/lipase was the only strong extracellular enzyme activity detected (mean 3.33): weak esterase, lipase, and leucine aminopeptidase activities were found with some strains (mean activities of 1.08, 1.53, and 1.40, respectively). Very strong leucine aminopeptidase activity (4.5) was associated with the cells. Cell-associated trypsin, esterase/lipase, acid phosphatase, and phosphoamidase were also found. Neither extracellular nor cell-associated hydrolase profiles changed significantly when cells were grown in skim milk or mineral salts medium at either 5 or 20 degrees C. Similarly, added calcium did not seem required for synthesis of any of the enzymes. The extracellular enzyme profiles differed considerably from those of the cell-associated enzymes for all strains tested. An extracellular proteinase-deficient mutant of strain 32A (RM14) failed to produce significant quantities of extracellular esterase/lipase activity. Production of cell-associated enzymes was unaffected by the mutation. These results suggest that the Analytab API ZYM system may be useful in identifying psychrotrophs isolated from milk.
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PMID:Determination of the extracellular and cell-associated hydrolase profiles of Pseudomonas fluorescens sp. using the Analytab API ZYM system. 308 7

1. Protease and deaminase activities and the metabolism of peptides were measured in rumen fluid from ciliate-free sheep and from sheep with a limited population of small entodinia. The same measurements were repeated following inoculation of the latter group with a more typical mixed ciliate population. 2. Protease and dialanine uptake activities of mixed rumen micro-organisms were not significantly influenced by protozoa. Trialanine uptake, leucine aminopeptidase (EC 3.4.11.1), deaminase and trypsin-like protease activities were 70, 107, 73 and 91% higher with the limited population, and 72, 58, 64 and 55% higher when mixed protozoa were present, indicating a major role for the protozoa in these activities.
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PMID:Microbial protein and peptide metabolism in rumen fluid from faunated and ciliate-free sheep. 330 17

Benzoyl- and isopentenoyl phosphoric triamides (BPA and IPA) strongly inhibited urease activities from jack bean, soybean, watermelon seed, Proteus mirabilis, P. rettgeri, P. vulgaris, Mycobacterium smegmatis, and Ureaplasma urealyticum. Their I50 values (the final concentration causing 50% inhibition), independent of enzyme source, were 2-21 nM, which are about 1,000-fold lower than that of caprylohydroxamic acid, one of the most potent urease inhibitors. ATP-urea amidolyase activity was inhibited 50% by BPA at a higher concentration of 0.28 mM, but was not affected by IPA even at 1.3 mM. Thirteen kinds of hydrolases (trypsin, chymotrypsin, thermolysin, leucine aminopeptidase, papain, lipase, alpha-amylase, glucuronidase, asparaginase, arylsulfatase, alkaline phosphatase, acid phosphatase, and true cholinesterase), two oxidoreductases (catalase and alcohol dehydrogenase), three transferases (glutamic-oxaloacetic aminotransferase, gamma-glutamyl transpeptidase, and arylsulfotransferase) and two kinases (pyruvate kinase and creatine kinase) were not affected at all even at 1 mM BPA and IPA. Exceptionally, pseudo-cholinesterase from human serum was inhibited by BPA and IPA, whose I50 values were 70 nM and 10 muM, respectively, using acetylthiocholine as a substrate. These values increased to 0.55 muM and 54 muM, respectively, when acetylcholine was used as a substrate. These results show that N-acylphosphoric triamides potently and specifically inhibit urease activity at concentrations of nM order.
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PMID:Specific inhibition of urease by N-acylphosphoric triamides. 384 42

The distribution and metabolism of [(14)C]aflatoxin B(1) in chicken tissues were further investigated. Previously dried and frozen ethyl acetate extracts of liver, heart, gizzard, breast, leg, blood, and fecal samples were obtained from either layer or broiler chickens fed subclinical levels of [(14)C]aflatoxin B(1). Treatment of these extracts with either carboxypeptidase A, leucine aminopeptidase, pepsin, or trypsin revealed that an average of 50% of the (14)C detected in the acetate extracts was a liberated peptide (or amino acid) conjugate of [(14)C]aflatoxin B(2a). When a prepared standard of B(2a) was made by incubation of B(1) with cold dilute aqueous HCl, the R(f) values and absorbance maxima were identical with those of the tissue extracts after enzymatic treatment.
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PMID:Further characterization of tissue distribution and metabolism of (14C)aflatoxin B1 in chickens. 461 34

The sensitivity of highly purified human fibroblast interferon and partially purified human leukocyte interferon to several proteolytic and glycolytic enzymes was determined with respect to antiviral activity, isoelectric point, molecular weight, and thermal stability. Leucine aminopeptidase altered the distribution of isoelectric points for both interferons but produced little change in molecular weights; this enzyme somewhat reduced the activity of only leukocyte interferon. Treatment of fibroblast interferon with carboxypeptidases A and B did not greatly decrease antiviral activity, but it did slightly reduce the molecular weight of the interferon and substantially altered the distribution of isoelectric point values; similar treatment of leukocyte interferon caused some loss in activity, especially of the 17,000-molecular-weight species. Both interferons were inactivated rapidly by treatment with the endoproteases trypsin, pepsin, bromelain, and subtilisin. Chymotrypsin shifted the isoelectric points of both interferons, but only leukocyte interferon was significantly inactivated. Treatment with neuraminidase and beta-galactosidase changed the isoelectric point distribution but did not affect the activity or thermal stability of either interferon; such a treatment reduced the molecular weight of fibroblast interferon and the size heterogeneity of leukocyte interferon. Treatment with neuraminidase and then leucine aminopeptidase greatly reduced the activity of both interferons, especially leukocyte interferon. The data indicate that biologically active forms of fibroblast and leukocyte interferons can be distinguished by their relative sensitivity to certain proteases.
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PMID:Enzymatic modifications of human fibroblast and leukocyte interferons. 616 Feb 60

Trypsin/creatinine clearance ratio--a recently proposed screening test for pancreatic cancer--was assessed in 45 subjects (17 control subjects, 15 patients with pancreatic cancer, and 13 with chronic pancreatitis). A statistically significant increase of the ratio was detected not only in pancreatic cancer, but also in chronic calcifying pancreatitis. Thus, the previously reported clinical usefulness of the test in pancreatic cancer diagnosis was not substantiated by the present data. Although not fully investigated as yet, reasons for an abnormal ratio are probably independent of the neoplastic or inflammatory nature of the pancreatic disease. Science renal enzyme excretion (alpha-glucosidase, gamma-glutamyltranspeptidase, leucine aminopeptidase) was not found to be invariably elevated when trypsin/creatinine clearance ratio was increased, tubular damage cannot be assumed as constituting the only reason for an altered clearance ratio.
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PMID:Role of trypsin/creatinine clearance ratio in the differential diagnosis of chronic pancreatic disease. 616 44

Treatment of liver plasma membranes with trypsin at low concentrations (1 to 2 microgram/mg of protein) caused at 3- to 4-fold increase in alpha-specific [3H]epinephrine binding. The change was due to an increase in the number of high affinity binding sites, with no change in the dissociation constant. With increasing trypsin concentrations, the dissociation constant was decreased and there was a progressive loss of binding. Elastase, papain, and thermolysin caused similar effects, whereas the thrombin, leucine aminopeptidase, phospholipase A2, phospholipase C, phospholipase D, and detergents did not cause an increase in [EH]epinephrine binding. The increase in epinephrine high affinity binding sites was correlated with a loss of high affinity [3H]-dihydroergocryptine binding sites which also bind [3H]epinephrine with low affinity (El-Refai, M. F., Blackmore, P. F., and Exton, J. H. (1979) J. Biol. Chem. 254, 4375-4386). Incubation of membranes with the alpha blockers dihydroergocryptine (50 nM) and phenoxybenzamine (20 nM) prior to protease treatment diminished the increase in [3H]epinephrine binding induced by trypsin (1.5 microgram/mg). The concentration dependence and time course of trypsin actions on 70 nM [3H]epinephrine binding and 10 nM [3H]dihydroergocryptine binding are consistent with a trypsin-mediated conversion of low affinity epinephrine binding sites to high affinity epinephrine binding sites.
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PMID:Effects of trypsin on binding of [3H]epinephrine and [3H]-dihydroergocryptine to rat liver plasma membranes. Evidence for interconversion of binding sites. 624 49

We have demonstrated that incubation of rat liver microsomes with N-hydroxy-2-acetylaminofluorene (N-OH-AAF) leads to formation of a 2-nitrosofluorene-membrane lipid adduct. This adduct exists as a nitroxyl free radical, termed N-O-LAF, in its oxidized state. When microsomes were incubated with the sulfhydryl binding agent, rho-hydroxymercuribenzoate, a larger amount of N-OL-LAF formed. We interpret this as a slowdown in the rate of endogenous chemical reduction of carcinogen-membrane lipid adduct. In this paper we present evidence that N-OH-AAF is deacetylated by a microsomal enzyme to form N-hydroxy-2-aminofluorene and this is then oxidized to 2-nitrosofluorene which adds covalently to membrane lipid double bonds to form N-O-LAF. Various antioxidants, peroxidase inhibitors, and P450 substrates and inhibitors were ineffective in altering the amount of N-O-LAF formed from N-OH-AAF; but two esterase inhibitors, dietyl-rho-nitrophenylphosphate and alpha-toluene-sulfonyl fluoride, prevented N-O-LAF formation. Of the following purified enzymes tested: porcine liver carboxyl esterase, pepsin, chymotrypsin, cathepsin D, ficin, papain, leucine aminopeptidase, Naja naja phospholipase, acetylcholinesterase (type I), trypsin (type I and V) and epoxide hydrase; only carboxyl esterase was effective in deacetylating N-OH-AAF.
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PMID:The deacetylation of N-hydroxy-2-acetylaminofluorene by rat liver microsomes and carboxyl esterase. 626 Mar 32

Partially purified extracts from neuroblastoma X glioma hybrid cells 108CC15 inhibit, like opioids, the prostaglandin E1-evoked formation of cyclic AMP in a dose-dependent manner in the same hybrid cells. The inhibition is prevented by the opioid antagonist naloxone. In addition, the same extract competes with [3H]naloxone and [3H]Leu-enkephalin for binding to opioid receptors of hybrid cell membranes and to a specific antiserum, respectively. The opioid activity in the extracts is destroyed by carboxypeptidase A and leucine aminopeptidase, but not by trypsin. Further purification of the extracts by HPLC, TLC, or high-voltage paper electrophoresis reveals in each case two active fractions which behave like Met- and Leu-enkephalin. The Met-enkephalin-like, but not the Leu-enkephalin-like, fraction is inactivated by treatment with BrCN. Dimethylaminonaphtylsulfonyl (dansyl) derivatives of Met- and Leu-enkephalin correspond to [3H]dansyl derivatives of Met-like substances from hybrid cells. Three to four times as much Met-enkephalin-like as Leu-enkephalin-like material is present in the extract. The overall concentration of opioid peptides in the hybrid cells varies between 0.03 and 1.0 pmol Leu-enkephalin equivalents per mg protein. The amount of opioids in the hybrid cells is strongly dependent on the cell density. The findings suggest that neuroblastoma X glioma hybrid cells contain opioid peptides that are very similar, if not identical, to Met- and Leu-enkephalin. Opioid activity can also be detected in other neuronal cell lines and even in glioma cells.
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PMID:Neuroblastoma X glioma hybrid cells synthesize enkephalin-like opioid peptides. 628 22

Indirect immunofluorescence was used to establish a domain-specific marker for hepatocyte plasma membranes. In frozen sections of fixed rat liver (0.5-4 microns), antibodies directed against rat intestinal leucine aminopeptidase (LAP) recognized an antigen that was restricted to the bile canalicular plasma membrane. Fluorescence was not observed on the sinusoidal or lateral membranes, and intracellular staining was not detected. The liver antigen was identified as LAP, based on its chemical similarity to intestinal LAP. First, immunoprecipitation experiments using trypsin-solubilized intestinal LAP (G-200 fraction, 91% pure) established a correlation between the loss of LAP enzyme activity from the soluble fraction and the appearance in the specific immunoprecipitates of polypeptides migrating on SDS PAGE between 110,000 and 130,000 daltons. The antigen precipitated from a detergent extract of liver plasma membranes had the same electrophoretic mobility. Second, the chymotryptic map of the major band in the liver immunoprecipitate was similar to that of purified intestinal LAP.
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PMID:A domain-specific marker for the hepatocyte plasma membrane: localization of leucine aminopeptidase to the bile canalicular domain. 630 8


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