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)

Hydrolysis of ursodeoxycholyl-p-aminobenzoic acid (PABA-UDCA), a synthetic bile acid conjugate used for the evaluation of the activity of intestinal bacterial growth, was studied with pancreatic enzymes, carboxypeptidase A, carboxypeptidase B, trypsin alpha-chymotrypsin, cholylglycine hydrolase, liver homogenate, small intestinal homogenates, and plasma, in comparison with the hydrolysis of glycocholic acid, ursodeoxycholyl-L-leucine (L-Leu-UDCA), and ursodeoxycholyl-L-lysine (L-Lys-UDCA). PABA-UDCA was specifically cleaved by bacterial cholylglycine hydrolase to ursodeoxycholic acid and para-aminobenzoic acid (PABA), but not by pancreatic enzymes. L-Leu-UDCA was cleaved by pancreatic enzymes, carboxypeptidase A, and cholylglycine hydrolase. L-Lys-UDCA was cleaved by pancreatic enzymes, carboxypeptidase B, and cholylglycine hydrolase. The small amount of glycocholic acid was cleaved by pancreatic enzymes and carboxypeptidase A and B, and cholylglycine hydrolase hydrolyzed glycocholic acid completely. In everted gut sac experiments, PABA-UDCA was absorbed by active transport in the rat terminal ileum, and the same rate of PABA was absorbed by passive diffusion in the four segments of the rat small intestine. These observations indicate that PABA-UDCA test can evaluate the activity of small intestinal bacterial growth.
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PMID:Hydrolysis and absorption of a conjugate of ursodeoxycholic acid with para-aminobenzoic acid. 263 32

The content of bradykinin (BK)-like peptides in rat dental pulp was significantly increased 1, 6 and 24 h after cavity formation at the neck of incisor. We have reported that enkephalin (EK)-like peptides in rat dental pulp were increased by cavity formation or BK. In the present study, the mechanism of the production of EK enhanced by BK was investigated using benzoyl-L-arginine-2-naphthylamide (BANA), a synthetic substrate. BK and its products cleft by carboxypeptidase B, des-Arg9-BK and arginine (Arg), activated the degradation of BANA. It is suggested that these substances may enhance the processing of enkephalins from precursor proteins. The activating effects were inhibited by EGTA. The BANA-degrading enzymes in lysosomal fraction were activated by BK, des-Arg9-BK and Arg, but the enzymes in supernatant were activated by Arg only. On the other hand, morphine and met-EK inhibited the production of BK-like peptides by trypsin from plasma kininogen. It is suggested that BK is cleft by carboxypeptidase B in pulp cell to des-Arg9-BK and Arg, which activate the lysosomal or soluble EK processing enzymes, and then the produced EK inhibits the production of BK from plasma kininogens in the pulp.
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PMID:[Interaction between bradykinin and enkephalins in rat dental pulp]. 264 47

Using sequence-specific radioimmunoassays before and after cleavage with trypsin and carboxypeptidase B, we have examined the occurrence and molecular nature of cholecystokinin (CCK) and gastrin peptides in bioactive (i.e. alpha-carboxyamidated) as well as non-amidated precursor forms in extracts from 13 human pheochromocytomas. All but one tumour contained amidated CCK, but only in moderate amounts (less than or equal to 20 pmol/g tissue). In contrast to the complete sulphation in tissues which normally produce CCK (the brain and small intestine), the amidated adrenal CCK peptides were poorly sulphated (less than or equal to 17%). Four pheochromocytomas, including the one without amidated CCK, contained between 28 and 0.2 pmol amidated gastrin/g, mainly in the form of sulphated gastrin-17. In addition, all tumours contained biosynthetic precursors of both CCK and gastrin. In most extracts there was more precursor than bioactive peptide(s), the progastrin concentration ranging up to 338 pmol/g. The results show that pheochromocytomas synthesize CCK and gastrin. The posttranslational processing differs, however, markedly from that of the principal CCK and gastrin producing tissues, with respect to both proteolytic cleavages and amino acid derivatization. This emphasizes that accurate quantitation in tumours requires assays which measure the translation products irrespective of their degree of processing.
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PMID:Cholecystokinin, gastrin and their precursors in pheochromocytomas. 271

Glandular kallikrein is known to promote contractions of the isolated, estrogenized rat uterus, perhaps independently of kinin formation. The recent availability of kinin receptor antagonists led us to study whether they might affect the oxytocic activity of kallikrein. DArg0-Hyp3-Thi5,8-DPhe7-bradykinin (8.5 x 10(-7) M) displaced the dose-response curves to both bradykinin (from 1.0 x 10(-9) to 4.0 x 10(-6) M) and kallikrein (from 4.7 x 10(-11) to 8.0 x 10(-9) M) approximately one order of magnitude to the right. This inhibition could not be due to a nonspecific effect on the uterine muscle, as the contractile response to oxytocin was not altered. In addition, carboxypeptidase B (a potent kininase) and kinin antibodies reduced the contractile response to kallikrein by 70 and 60%, respectively. Removal of the intervening agent restored the normal response. The effect of kallikrein depended on its enzymatic activity, inasmuch as kallikrein inactivated with D-Phe-Arg-Arg-CH2Cl was not oxytocic. Prolonged or multiple exposures to kallikrein completely abolished uterine response, whereas the effect of bradykinin was unaltered. Uterine horns rendered insensitive to kallikrein by prolonged exposure still contracted in response to trypsin. Kininogen was present in the uterine tissue in a concentration of 1.5 +/- 0.3 ng of bradykinin equivalents per mg wet wt. No more than 15.9 +/- 1.2% of this total was due to plasma contamination. Only 21.5 +/- 2.9% of total kininogen could be cleaved by kallikrein. We conclude that part of the oxytocic activity of kallikrein is related to generation of kinins from a kallikrein-sensitive kininogen present in the isolated rat uterus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Kinins contribute to the contractile effects of rat glandular kallikrein on the isolated rat uterus. 272 35

Diphtheria toxin contains a trypsin-sensitive region with 3 closely spaced arginines in the sequence (Asn189, Arg190, Val191, Arg192, Arg193, Ser194). Cleavage of the toxin to yield A- and B-fragments ("nicking") appears to occur in a stochastic manner after either of these arginine residues. Isoelectric focusing of A-fragment prepared in vitro showed four bands of varying intensity with pI between 4.5 and 5.0, three of which could be accounted for by the three different cleavage sites. Exposure of cells with surface-bound toxin to pH less than 5.3 induces translocation of A-fragment to a position where it is shielded from external Pronase, presumably in the cytosol. A-fragment translocated in this manner had the same pI as the most acidic A-fragments, indicating that only A-fragments lacking both Arg192 and Arg193 are translocation-competent. This was confirmed by amino acid sequencing. Treatment of A-fragment with carboxypeptidase B eliminated the two bands with the highest pI while there was a concomitant increase in the bands corresponding to the two most acidic A-fragments. Such treatment of nicked diphtheria toxin increased the amount of translocated A-fragment and the ability of toxin to form cation-selective pores in the cell membrane. The site of trypsin cleavage therefore appears to be one of the factors limiting toxin entry to the cytosol.
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PMID:Translocation of diphtheria toxin A-fragment to the cytosol. Role of the site of interfragment cleavage. 276 83

Dynorphin B (rimorphin) is formed from dynorphin B-29 (leumorphin) by the action of a thiol protease from rat brain membranes. This represents a "single-arginine cleavage" between threonine-13 and arginine-14 of the substrate. In isotope dilution experiments we find that the radioactivity from radiolabelled dynorphin B-29, which appears in dynorphin B during incubation with the enzyme preparation, is not diminished by addition of a high concentration of dynorphin B-Arg14. Moreover, in pulse-chase experiments, radioactivity that appeared in dynorphin B-Arg14 did not decrease, nor did the radioactivity in dynorphin B increase, after chasing with a high concentration of non-radioactive dynorphin B-29. These results indicate that although some dynorphin B-Arg14 is formed by the impure enzyme preparation, it is not an intermediate in the conversion of dynorphin B-29 to dynorphin B. Thus the formation of dynorphin B does not involve the action of a trypsin-like enzyme followed by removal of arginine-14 by a carboxypeptidase B-like enzyme. It appears that a single enzyme converts dynorphin B-29 to dynorphin B in a single step.
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PMID:Neuropeptide processing by single-step cleavage: conversion of leumorphin (dynorphin B-29) to dynorphin B. 286 69

To find a possible explanation for the selective hepatic conjugation of bile acids with glycine or taurine, the N-acyl amidates of cholic acid and a number of amino acids and amino acid analogues were synthesized, and their susceptibility to hydrolysis by pancreatic juice, gastric juice, serum, or small intestinal mucosal enzymes was measured. Deconjugation by pure carboxypeptidase A and B was also examined, and hydrolysis by these tissue fluids and enzymes was compared with that mediated by a bacterial cholylglycine hydrolase. Human pancreatic juice efficiently hydrolyzed cholyl conjugates of all neutral-L-amino acids (cholyl-L-alanine, cholyl-L-valine, cholyl-L-leucine, and cholyl-L-tyrosine), except cholylglycine. The net hourly rate of hydrolysis (in micromoles per milligram protein per hour) increased when the terminal residue was aromatic or branched aliphatic, and appeared to be specific for L-alpha-amino acids as cholyl-beta-alanine and cholyl-D-valine were not cleaved. From cholyl glycylglycine, only the terminal glycine was efficiently removed. Cholyltaurine and cholyl conjugates with the methyl and propyl analogues of taurine were resistant to hydrolysis. Two basic amino acid conjugates (cholyl-L-lysine and cholyl-L-arginine) were cleaved, whereas conjugates of acidic amino acids (cholyl-aspartate and cholyl-cysteate) were not cleaved. Studies using pure enzymes showed that bovine carboxypeptidase A hydrolyzed the cholyl conjugates of the neutral L-alpha-amino acids with similar specificity as observed for the human pancreatic juice, whereas bovine carboxypeptidase B cleaved the basic amino acid conjugates. Cholyl-L-lysine and cholyl-L-arginine were also cleaved by serum and plasma, which are known to possess carboxypeptidase activity. Cholyl conjugates were not cleaved by gastric juice, by trypsin, or by homogenates of rat small intestinal mucosa. In contrast, all cholyl conjugates were cleaved by a bacterial cholylglycine hydrolase. These experiments indicate that glycine and taurine amidates of cholic acid differ from a number of other conjugates with neutral and basic amino acid in being resistant to hydrolysis by pancreatic and plasma carboxypeptidases.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Pancreatic carboxypeptidase hydrolysis of bile acid-amino conjugates: selective resistance of glycine and taurine amidates. 286

Proteins extracted from suboesophageal ganglia of Squilla mantis, an arthropod shown to be sensitive in vivo to opiates and to contain native opioid like peptide(s), were fractionated by gel filtration into three pools according to their molecular weight: A (Mr greater than 65,000), B (10,000 less than Mr less than 65,000) and C (Mr less than 10,000). None of these pools showed any immunoreactivity when radioimmunoassayed using antisera raised against Met-enkephalin either before or after sequential trypsin/carboxypeptidase B proteolysis. Further purification of pool C by HPLC followed by RIA using antibodies directed to Met-O-enkephalin,Leu-enkephalin,Dynorphin 1-13 and human beta-endorphin, showed only a trace amount of Met-enkephalin cross-reactivity (about 10 fmoles/mg of protein extract). No detectable amount of Leu- or Met-enkephalin was found after HPLC fractionation of proteolyzed pool B. Radioreceptor assay of HPLC fractions derived from trypsin/carboxypeptidase B treated pools B and C showed major areas of activity common to both pools, but nevertheless with differing retention times compared to the standard opioid peptides used.
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PMID:RIA/chromatographic evidence for novel opioid peptide(s) in Squilla mantis ganglia. 287 12

Two neuropeptide precursor processing enzyme systems were characterized in the rat brain cortex and bovine neurohypophysis and corpus luteum. The first one combines the action of a 90 kDa endoprotease which cleaves somatostatin-28 before the Arg-Lys doublet and that of an aminopeptidase B-like enzyme. The second system associates the action of a 58 kDa endoprotease cleaving pro-ocytocin/neurophysin (1-20) after the Lys-Arg dibasic moiety and a carboxypeptidase B-like activity. Both systems appear to be located in membrane-limited secretory vesicles of the producing organs, and to exhibit the properties of metallo-enzymes sensitive to divalent cation chelators. In contrast, they do not show the characteristics of serine-proteases and of trypsin-like enzymes. Studies with substrate analogs selectively modified at the basic doublet indicated that the integrity of both basic amino acids is essential but that conformational parameters, probably governed by the amino acid sequences flanking the basic doublet, play an important role. These data will be discussed in relation to a hypothesis on the predicted preferred secondary structure of these restriction loci.
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PMID:Somatostatin-28 and pro-ocytocin/neurophysin convertases: basic pair selective endoproteases involved in pro-hormone processing in the rat brain cortex and bovine corpus luteum. 290 27

Using radioimmunoassays specific for essential processing sites of human progastrin in combination with chromatography before and after cleavage with trypsin and carboxypeptidase B, we have examined antral biopsy specimens and serum from 10 hypergastrinemic patients with fundic atrophic gastritis and 7 normal control subjects. Four types of processing were studied: N-terminal proteolysis (at the N-terminus of component I, gastrin 34, and gastrin 17); C-terminal proteolysis (at the C-terminus of the amide donor, glycine93 in preprogastrin); alpha-carboxyamidation (of phenylalanine92); and O-sulfation (of tyrosine87). The results show that progastrin during permanent G-cell hypersecretion is less completely processed with respect to C-terminal proteolysis, alpha-amidation, and tyrosine-sulfation. In contrast, the degree of N-terminal proteolysis is normal. Thus, the processing of progastrin adjacent to the active site of gastrin is more restrictively controlled than N-terminal processing during G-cell hypersecretion associated with pernicious anemia.
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PMID:Progastrin processing during antral G-cell hypersecretion in humans. 292 53


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