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:3.4.21.1 (chymotrypsin)
10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The process by which the egg-yolk protein precursor vitellogenin is biosynthesized, assembled and secreted by Xenopus laevis (South African clawed toad) liver was studied. It was previously shown in other laboratories that vitellogenin contains the two egg-yolk proteins lipovitellin (mol.wt. 140 000) and phosvitin (mol.wt. 35 000). 2. Evidence is presented which shows that Xenopus liver microsomal fractions synthesize precursors of vitellogenin. These precursors were solubilized from the membranes with detergent and analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. This analysis indicated that there is only one precursor polypeptide, and this has mol.wt. approx. 200 000 +/- 20 000. This demonstrates that the egg-yolk proteins are translated as part of this larger polypeptide. 3. Experiments also demonstrate the existence of a microsomal proteinase which is able to cleave the precursor into smaller fragments. The nature of these fragments provided some indirect evidence that phosvitin and lipovitellin light chains are situated together within the precursor molecule. 4. These precursor data fit in well with structural studies on serum vitellogenin, since it has been shown that the latter protein consists of two identical subunits each with a mobility on sodium dodecyl sulphate/polyacrylamide gels identical with that shown by the microsomal precursor. This indicates that both the intracellular precursor and subunit of vitellogenin have similar (but not necessarily identical) molecular weights. 5. It was also shown that trypsin or chymotrypsin can cleave the serum vitellogenin into leucine- and serine-rich fragments which resemble lipovitellin and phosvitin respectively. Attention is, however, drawn to the fact that the serine-rich fragment is not identical with phosvitin, since it contains eight times more leucine than that expected for the authentic phosvitin molecule [Penning (1976) Ph.D. Thesis, University of Southampton].
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PMID:Studies on the biosynthesis, assembly and secretion of vitellogenin, an oestrogen-induced multicomponent protein. 84 74

Cytosol of horse blood polymorphonuclear leucocytes contains an inhibitor active against neutral proteinases from the granules of these cells and against chymotrypsin, elastases I and II from pig pancreas, but not against trypsin. A method has been elaborated to isolate and purify this inhibitor by means of salting out with ammonium sulphate (45---70% saturation), followed by chromatography and rechromatography on a column of DEAE-Sephadex A-50. The preparation obtained is homogeneous during polyacrylamide gel electrophoresis in the presence of 0.1% sodium dodecylsulphate after reduction with 2-mercaptoethanol. It is a thermolabile protein soluble at its isoelectric point (pH 5.38) and having a molecular weight of 35200 but aggregating in solutions of low ionic strength and irreversibly precipitating during dialysis at pH 4.0. The results obtained show the similarity of this inhibitor isolated from horse blood leucocyte cytosol to other inhibitors isolated from human or pig blood leucocytes.
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PMID:A polyvalent proteinase inhibitor from horse-blood-leucocyte cytosol. Isolation, purification and some molecular parameters. 84 42

Isolation of tropoelastin is complicated by the presence of a neutral protease closely associated with tropoelastin that is capable of sequentially degrading tropoelastin to small peptides. Substrate and inhibitor specificities of this neutral protease associated with purified tropoelastin were examined. The enzyme displayed proteolytic activity against casein, and esterase activity was detected when assayed against N-tosyl-L-arginine methyl ester but not against tert-butyl-oxycarbonyl-L-alanine p-nitrophenyl ester. No appreciable elastinolytic activity was detectable against either insoluble sodium dodecyl sulfate treated elastin or maleylated tropoelastin. The enzyme was not inhibited by the chymotrypsin inhibitor toluenesulfonylphenylalanine chloromethyl ketone. The enzyme was inhibited by phenylmethanesulfonyl fluoride and, to various degrees, by metal chelators. Tosyllysyl chloromethyl ketone, epsilon-aminocaproic acid, and Aprotinin (pancreatic trypsin inhibitor--Kunitz type), all inhibitors of trypsin-like enzymes, were very effective inhibitors, as were soybean trypsin inhibitor and human alpha-1-antitrypsin. The data suggest that the tropoelastin-associated enzyme is a neutral serine protease with trypsin-like specificity.
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PMID:Trypsin-like neutral protease associated with soluble elastin. 90 57

In this paper we discribe a method for the isolation of trypsin inhibitors from the tentacles of the annelid Sabellastarte indica Savigny. These inhibitors - now homogeneous in their molecular weight - can be characterised by sodium dodecylsulfate-acrylamide gel-electrophoresis, in their inhibitory activity towards trypsin, plasmin and chymotrypsin. The inhibitors from Sabellastarte indica possess a stoichiometric binding relation of 2:1 for trypsin, lysine being the amino-acid in the reactive centre of the inhibitor responsible for interaction with trypsin. The reactive centre for trypsin is not identical with the reactive centre which binds chymotrypsin and does not influence the binding of chymotrypsin. These newly described inhibitors are therefore multiheaded, a type not previously described for invertebrates.
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PMID:[Further characterisation of trypsin inhibitors in the polychaet Sabellastarte indica (Savigny), II (author's transl)]. 95 30

Cells obtained from chick embryo tendons incorporate isotopically labeled glucosamine and mannose into the pro-alpha1 and pro-alpha2 chains of procollagen as judged by sodium dodecyl sulfate-gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The label was further localized to the propeptides of pro-alpha1 and pro-alpha2 by its chromatographic behavior after digestion with bacterial collagenase or alpha-chymotrypsin. Carbohydrate analysis of isolated pro-alpha chains showed the presence of labeled galactosamine in addition to mannose and glucosamine. Resistance to mild alkaline hydrolysis suggested that greater than 90% of the oligosaccharide units are not linked to the propeptide backbone by either serine or threonine.
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PMID:Carbohydrate moieties of procollagen: incorporation of isotopically labeled mannose and glucosamine into propeptides of procollagen secreted by matrix-free chick embryo tendon cells. 106 Nov 25

Cyanogen bromide treatment of thymidylate synthetase of Lactobacillus casei, which had been converted to a ternary complex with [2-14c] FdUMP and 5,10-methylene-tetrahydrofolate followed by S-carboxymethylation, yielded at least four visible peptide bands, the largest with a molecular weight of about 13,000, on polyacrylamide gel electrophoresis in sodium dodecyl sulfate-urea. Identical results were obtained with enzyme that had all four of its cysteinyl residues S-carboxymethylated with iodo [I-14C] acetate in the absence of FdUMP and cofactor. In each case, only the second band from the top of the gel (CN2), with an approximate molecular weight of 10,000= was labeled. Analysis of CN2 that had been labeled with [2-14C] FdUMP and nonradioactive iodoacetate and of that labeled only with iodo[1-14C] acetate revealed that their amino-acid contents were almost identical except for the presence of two S-carboxymethyl (Cm)-cysteinyl residues in the latter peptide and only one in FdUMP-CN2. A nonapeptide was isolated from (Cm)2-CN2 after chymotrypsin digestion that contained the following sequence by dansyl-Edman analysis: Ala-Leu-Pro-Pro-[Cm-Cys]-His-Thr-Leu-Tyr. This peptide was found to be located on the NH2-terminal end of CN2. Automatic sequence analysis of the first 13 residues of (Cm)2-CN2 and of the FdUMP-containing CN2 yielded identical results except for the fifth, or cysteinyl, residue, which could not be identified in the latter peptide. These findings strongly suggest that FdUMP is linked to a cysteinyl residue in thymidylate synthetase that has been inactivated irreversibly by this nucleotide.
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PMID:Amino acid sequence at the FdUMP binding site of thymidylate synthetase. 106 57

A chymotrypsin-like enzyme (EC 3.4.21.-) was purified from granules of human neutrophiles (polymorphonuclear leucocytes). The isolation procedure included differential salt extractions of the granules followed by affinity chromatography on 4-phenylbutylamine-Affi-Gel. This rapid purification method resulted in obtaining pure enzyme in relatively high yield in short time. The purified granulocyte chymotrypsin-like enzyme has a minimum Mr of 22 378, calculated from its amino acid composition. The Mr value obtained by sodium dodecyl sulphate gel electrophoresis was 20 000-23 000. The enzyme did not react with antibodies which are monospecific to granulocyte elastase. The granulocyte chymotrypsin-like enzyme was inactivated by Dip-F and by the chloromethyl ketone derivatives Z-PheCH2Cl and Z-(Gly)2-PheCH2Cl but not by Tos-PheCH2Cl. It therefore appears that the enzyme has serine and histidine side chains in its active site, like pancreatic chymotrypsin. The granulocyte enzyme substrate specificity is similar to that of pac-Tyr-Nan and Ac-Phe-1-ONap. It also has an intrinsic weak hydrolytic activity towards some classical elastase substrates such as Boc-Ala-ONp and Ac-DL-Ala-1-ONap. The granulocyte enzyme is inhibited by human serum and by human alpha1-antitrypsin. Its affinity for alpha1-antitrypsin is weaker than that of granulocyte elastase for the same inhibitor. The enzyme is stable at neutral pH at 37 degrees C, but unstable at pH 3.5 and at elevated temperature.
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PMID:A rapid method for purification of human granulocyte cationic neutral proteases: purification and characterization of human granulocyte chymotrypsin-like enzyme. 108 Oct 3

Human milk contains a bile salt-stimulated lipase in amounts that, at pH 6.5 and in the presence of bile salts, might account for a total hydrolysis of the milk triacylglycerols in less than 30 min. In the absence of bile salts the enzyme has no activity against milk fat or against emulsified trioleylglycerol. The primary bile salts sodium cholate and sodium chenodeoxycholate and their taurine and glycine conjugates, but not the secondary bile salt sodium deoxycholate or its taurine and glycine conjugates, caused a pronounced activation of the enzyme against emulsified trioleylglycerol. The lipase was stable at pH 3.5 and 37 degrees C for 1 hour. It was inactivated when incubated with trypsin or chymotrypsin at pH 6.5 but these inactivations were almost abolished in the presence of bile salts. High concentrations of pepsin slowly inactivated the enzyme at pH 4.0. The bile salt-stimulated lipase in human milk is thus stable enough to be active in the intestine, and it is present in high enough activity to contribute significantly to the hydrolysis of the milk triaclyglycerols in the intestine.
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PMID:Human milk lipases. III. Physiological implications of the bile salt-stimulated lipase. 114 84

The molecular weight of phallolysin, the toxic haemolysin from Amanita phalloides, was established by gel chromatography to be 30000 daltons. The isoelectric point (I.P.) was found in Ampholine pH 7-10 at 8.34. In Ampholine pH 7-9 the gel chromatographically homogeneous phallolysin was separated into phallolysin A (I.P. 8.06) and phallolysin B (I.P. 7.49). Sodium dodecylsulphate-polyacrylamide gel electrophoresis indicated a molecular weight of 33000 daltons for phallolysin A. Phallolysin was thermo- and acid-labile. It was relatively stable in alkaline solutions. 8 M urea as well as 0.1% sodium dodecylsulphate caused irreversible denaturation. On the other hand, phallolysin showed resistance to diverse proteases (pepsin, trypsin, alpha-chymotrypsin, subtilisin, pronase E, bromelin, proteinase K) and also alpha-amylase and pancreatin. Treatment with proteinase K did not change the molecular weight and the isoelectric points of phallolysin. Resistance to proteases was not due to inhibition of proteases by phallolysin.
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PMID:Some physico-chemical properties of phallolysin obtained from Amanita phalloides. 117 97

Sporocysts from the protozoan parasite, Eimeria tenella, were isolated, preincubated with sodium taurocholate, and treated with various preparations of pancreatic enzymes. Crude trypsin, crude lipase, and purified alpha-chymotrypsin all could break the shells of sporocysts and release sporozoites. Purified trypsin was much less active than crude trypsin and purified lipase showed no activity at all. Specific inhibitors of chymotrypsin, tosyl-L-phenylalanyl chloromethane, diphenylcarbamyl chloride, and chymostatin inhibited the release of sporozoites by all the enzyme samples, whereas tosyl-L-lysyl chloromethane, a specific inhibitor of trypsin, exerted no inhibitory effect. It is thus postulated that chymotrypsin, not trypsin, is an essential enzyme involved in excystation of E. tenella. Purified chymotrypsin is recommended to replace crude trypsin in the vitro excystation of E. tenella as a likely improved procedure.
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PMID:Pancreatic chymotrypsin as the essential enzyme for excystation of Eimeria tenella. 118 37


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