Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The trypsin and chymotrypsin inhibitor from chick peas (CI) is stable in HCl 0.001 M -- 0.01 M and in KOH 0.01 M -- 0.05 M even after 24 h. Increased KOH concentrations decrease considerably the inhibitory activity already after 1 h. Maleyation and succinylation of the inhibitor resulted in almost full loss of its trypsin-inhibitory activity but had no effect on the chymotrypsin-inhibitory activity. A series of modifications directed towards tyrosyl residues showed that iodination influenced only the chymotrypsin-inhibitory activity; however, nitration and arsanilation affected not only the chymotrypsin-inhibitory activity but also the trypsin-inhibitory activity. Treatment of the inhibitor with CNBr and chloramine T resulted only in a decrease in the chymotrypsin-inhibitory activity indicating that the only methionine is involved in the chymotrypsin-inhibitory activity. When CI-fragment A, previously treated with trypsin at pH 3.75, was further treated with carboxypeptidase B, a release of three lysyl residues per mole protein was found. CI was separated by equilibrium chromatography on SP-Sephadex column into two isoinhibitors, CII and CIII, respectively. Both inhibited trypsin and chymotrypsin with the same specific activity as CI. They differed from each other only in a glutamyl, aspartyl, glycyl and alanyl residue.
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PMID:Trypsin and chymotrypsin inhibitor from chick peas. Selective chemical modifications of the inhibitor and isolation of two isoinhibitors. 4 22

Altered hemoglobin (Hb) has been found in the feces as a sequel to an upper gastrointestinal bleed. Active Hb antigen of increased anodic mobility was detected on immunoelectrophoresis of melena stools using a goat anti-Hb. The Hb derivative was also identified in polyacrylamide gel electrophoresis using 412 nm. absorbance. The alteration could be simulated in vitro by incubation of hemolysate with duodenal juice or purified carboxypeptidase B alone, or by a mixture of carboxypeptidases A and B. Treatment of hemolysate or purified Hb with acid, gastric juice, pepsin, pancreatic juice, bile, trypsin, or chymotrypsin failed to produce the characteristic alteration. Instead, no change, or production of alpha and beta chains, or gradual but complete elimination of the Hb antigen was seen. This latter all or none pattern is presumed to prevail in the large bowel on the basis of incubations of hemoglobin-feces mixtures. Individuals documented to be bleeding into the colon were found to have at least a portion of their Hb antigen in the unaltered form by immunoelectrophoresis. This finding may be of value in identifying the general origin of a gastrointestinal bleed.
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PMID:Appearance, properties, and origin of altered human hemoglobin in feces. 6 May 7

The reactive-site sequence of a proteinase inhibitor can be written as . . . -P3-P2-P1-P'1-P'2-P'3- . . . , where-P1-P'1-denotes the reactive site. Three semisynthetic homologues have been synthesized of the bovine trypsin-kallikrein inhibitor (Kunitz) with either arginine, phenylalanine or tryptophan in place of the reactive-site residue P1, lysine-15. These homologues correspond to gene products after mutation of the lysine 15 DNA codon to an arginine, phenylalanine or tryptophan DNA codon. Starting from native (virgin) inhibitor, reactive-site hydrolyzed, still active (modified) inhibitor was prepared by chemical and enzymic reactions. Modified inhibitor was then converted into inactive des-Lys15-inhibitor by reaction with carboxypeptidase B. Inactive des-Lys15-inhibitor was reactivated by enzymic replacement of the P1 residue according to Leary and Laskowski, Jr. The introduction of arginine was catalyzed by an inverse reaction with carboxypeptidase B, while phenylalanine or tryptophan were replaced by carboxypeptidase A. The reactivated semisynthetic inhibitors were trapped by complex formation with either trypsin or chymotrypsin. The enzyme - inhibitor complexes were subjected to kinetic-control dissociation, and the semisynthetic virgin inhibitors were isolated. The inhibitory properties of the semisynthetic inhibitors have been investigated against bovine trypsin and chymotrypsin and against porcine pancreatic kallikrein and plasmin. The homologues with either lysine or arginine in the P1 position are equally good inhibitors of trypsin, plasmin and kallikrein. The Arg-15-homologue is a slightly more effective kallikrein inhibitor than the Lys15-inhibitor. The semisynthetic phenylalanine and tryptophan homologues, however, are weak inhibitors of trypsin and still weaker inhibitors of kallikrein, but are excellent inhibitors of chymotrypsin. Their association constant with chymotrypsin is at least ten times higher than that of native Lys-15-inhibitor. A dramatic specificity change is observed with the phenylalanine and tryptophan homologues, which in contrast to the native inhibitor do not at all inhibit porcine plasmin. Thus, the nature of the P1 residue strongly influences the primary inhibitory specificity of the bovine inhibitor (Kunitz).
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PMID:Replacement of lysine by arginine, phenylalanine and tryptophan in the reactive site of the bovine trypsin-kallikrein inhibitor (Kunitz) and change of the inhibitory properties. 12 27

1. A simple, highly sensitive, specific fluorometric method for the determination of chymotrypsin is described. 2. The new substrate utilized in this assay, N-glutaryl-glycyl-glycyl-l-phenylalanine beta-naphthylamide (GGPNA), is readily soluble in water, stable and highly specific for chymotrypsin. It is not degraded by a large excess of carboxypeptidase B, elastase, thrombin or plasmin and is virtually resistant to trypsin. 3. GGPNA is extremely sensitive to the action of chymotrypsin and permits detection of enzyme concentrations as low as 1 ng/ml. Linearity between enzyme concentration and fluorescence produced is maintained up to at least 3000 ng/ml. 4. alpha2-Macroglobulin-bound chymotrypsin hydrolyzes GGPNA at a rate about 2/3 of that exhibited by the free enzyme. 5. Bile pigments in amounts normally found in duodenal juice or traces of blood do not interfere with the assay. 6. GG PNA which releases beta-naphthylamine upon hydrolysis is suitable also for colorimetric and histological determination of chymotrypsin.
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PMID:A new, highly sensitive and specific assay for chymotrypsin. 23 87

A rat uterine smooth muscle contracting substance was released into the superfusate of the dog's exposed canine pulp after noxious stimulation of the pulp by pricking, heat and electrical stimulation. This active substance was acid- and heat-resistant and was decomposed by carboxypeptidase B and alpha-chymotrypsin, but not by carboxypeptidase A and trypsin. This substance was also tested on several types of smooth muscle. Electrical activity of nerve cells in the reticular formation, which were sensitive to stimulation of the instep of the foot by pinching, was activated by the intrafemoral administration of the active substance. The algesic activity of this substance was examined in cantharidin blister base in man. This study conclusively demonstrated that the active substance of the pulp released by noxious stimulation produced pain and it was identified as bradykinin.
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PMID:Bradykinin as an algesic (pain producing) substance in the pulp. 42 98

The property of brain endopeptidases of attacking small biologically active polypeptides but not denatured proteins led us to compare them with pancreatic proteolytic enzymes with respect to hydrolysis of a synthetic peptide derived from bradykinin (Gly-Gly-Gly-Arg-bradykinin), free, bound to Affi-Gel 10, or bound to succinylated polylysine of 3,000 and 180,000 daltons, respectively. The data show that brain endopeptidases A and B only hydrolyze bradykinin in its free form, whereas trypsin, chymotrypsin, and carboxypeptidase B hydrolyze the polypeptide both free and covalently bound to a high molecular weight carrier. These results suggest that brain endopeptidases selectively hydrolyze low molecular weight polypeptides.
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PMID:Susceptibility of a peptide derived from bradykinin to hydrolysis by brain endo-oligopeptidases and pancreatic proteinases. 44 50

Cadmium-carboxypeptidase B was nitrated with tetranitromethane. The enzyme polymerized extensively during nitration. In the monomer nitrated Cd-carboxypeptidase B, 70% of the activity of Cd-carboxypeptidase B was retained. In order to identify the tyrosyl residues nitrated, the enzyme was digested with chymotrypsin and subtilisin and the nitrotyrosyl peptides were purified by affinity chromatography on antityrosyl-antibody-Sepharose conjugate followed by two-dimensional thin-layer chromatography. The major nitropeptides, representing 65% of the nitrotyrosyl label, were compatible with the segment of the sequence containing Tyr-240 and Tyr-259. Only 10% of the nitrotyrosyl label was found in the segment of Tyr-248. This indicates that the state of Tyr-248 in Cd-carboxypeptidase B differs from that in zinc-carboxypeptidase B where it shows chemical hyperreactivity due to its proximity to the metal ion.
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PMID:The reactivity of a functional tyrosyl residue in carboxypeptidase B. Nitration of the cadmium enzyme. 56 47

1. Phosphorylase b was inactivated three times more rapidly than phosphorylase a by a neutral, trypsin-like proteinase from rat intestinal muscle. Digestion of phosphorylase a produced a modified form which was deactivated by AMP. Removal of the pyridoxal phosphate cofactor increased the rate of inactivation of the b form by about 3-fold but the subceptibility of apophosphorylase a was no different from the holo form. 2. The extent of proteolysis of both holoenzyme forms, as guaged by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, was limited and similar digestion patterns were obtained in both cases. 3. With (32)P-labelled phosphorylase a as substrate, the initial event in the inactivation was the release of a trichloroacetic acid-soluble peptide from the N-terminus of the enzyme, leaving the original 100000 subunit form essentially unchanged. Subsequent proteolysis was restricted, producing derivatives of mol.wt. 85000, 70000 and 65000, none of which contained any radioactive label. 4. By treatment of inactivated phosphorylase b with carboxypeptidase B, it was shown that the intestinal muscle proteinase had cleaved approximately 3 -Lys-X and 3 -Arg-X bonds in the polypeptide. 5. The protective effects of various allosteric modulators of phosphorylase on the inactivation of the a and b forms were generally in agreement with the known roles of the modifiers. Glucose increased the susceptibility of phosphorylase a. 6. Inactivation of phosphorylase b by trypsin and chymotrypsin also resulted in limited proteolysis but, in both cases, the digestion patterns obtained on sodium dodecyl sulphate/polyacrylamide gels were different from each other and from the pattern obtained with the intestinal muscle proteinase. 7. Inactivation of phosphorylase b by the muscle proteinase is about 100 times more rapid than the effects produced by trypsin or chymotrypsin when the activities are compared on an equimolar basis. 8. Consideration is given to regulation of the rate of enzyme degradation intracellularly by modulation of the conformation and susceptibility of the enzyme via factors such as covalent modification, allosteric ligands and state of aggregation.
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PMID:The susceptibility of muscle phosphorylases a and b to digestion by a neutral proteinase from rat intestinal muscle. Comparison with the effects produced by pancreatic trypsin and chymotrypsin. 73 88

Carboxypeptidase B (peptidyl-L-lysine (-L-arginine) hydrolase, EC 3.4.12.3) has been isolated and purified to apparent homogeneity from activated extracts of human pancreas tissue. The purified enzyme has been shown to be a single polypeptide of 34 000 daltons. In this respect the enzyme from pancreatic tissue, designated native human carboxypeptidase B, differs from the two forms present in human pancreatic juice (fractions I and II), both of which are composed of two polypeptides of approximately 24 000 and 9000 daltons. In addition, the three forms of human carboxypeptidase B differ in electrophoretic mobility in polyacrylamide gel electrophoresis and in chromatographic behavior on DEAE-cellulose. Two immunological methods, micro-complement fixation and radioimmunoassay, have shown a high degree of structural similarity between the three forms of human carboxypeptidase B. Micro-complement fixation experiments indicate that the amino acid sequences of the three enzymes differ by less than one percent. In vitro digestion studies have indicated that trypsin alone is sufficient to convert native carboxypeptidase B to carboxypeptidase B II. However, no combination of trypsin, chymotrypsin, and/or elastase was capable of converting native carboxypeptidase B to carboxypeptidase B I in vitro.
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PMID:Human carboxypeptidase B. II. Purification of the enzyme from pancreatic tissue and comparison with the enzymes present in pancreatic secretion. 100 23

The seminal plasma and sperm of fresh and stored poultry semen were analyzed for the presence of eight peptide hydrolase enzymes. Five enzymes: carboxypeptidase A, carboxypeptidase B, chymotrypsin, glycylglycylglycine hydrolase and pepsin were not present in either plasma or sperm. An aminopeptidase-like and a cathepsin-like activity were found in seminal plasma and sperm while a trypsin-like activity was found in sperm only. There was a significant difference between full sib groups with respect to aminopeptidase-like activity in fresh and stored plasma, while storage for 24 hours resulted in a significant increase in trypsin-like activity of sperm. The aminopeptidase-like activity of fresh sperm was positively correlated with duration and percent fertility of fresh semen, while neither cathepsin-like activity nor trypsin-like activity were correlated with fertility of fresh or stored semen except for a positive correlation between the cathepsin-like activity of fresh plasma and percent fertility of fresh semen.
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PMID:The activity of some peptide hydrolase enzymes in fresh and stored poultry semen from full sib groups of males and their relationship to fertility. 118 12


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