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)

In this paper, we present the amino-terminal sequence of rat tonin, an endopeptidase responsible for the conversion of angiotensinogen, the tetradecapeptide renin substrate, or angiotensin I to angiotensin II. It is shown that isoleucine and proline occupy the amino- and carboxy-terminal residues respectively. The N-terminal sequence analysis permitted the identification of 34 out of the first 40 residues of the single polypeptide chain composed of 272 amino acids. These results showed an extensive homology with the sequence of many serine proteases of the trypsin-chymotrypsin family. This information, coupled with the slow inhibition of tonin by diisopropylfluorophosphate, classified this enzyme as a selective endopeptidase of the active serine protease family.
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PMID:N-Terminal amino acid sequence of rat tonin: homology with serine proteases. 21 93

A major CNBr fragment of glutathione reductase, peptide Q [Krohne-Ehrich, G., Schirmer, R.H. & Untucht-Grau, R. (1977) Eur. J. Biochem. 80, 65-71], was further fractionated by trypsin, chymotrypsin, thermolysin and clostripain digestion. The peptides were isolated and most of them were sequenced by solid-phase Edman degradation. The whole peptide Q was sequenced N-terminally up to position 51 by the same technique. A total sequence of 128 amino acids (28% of the whole protein) was obtained and could be localized in the electron density map [Schulz, G.E., Schirmer, R.H., Sachsenheimer, W. & Pai, E.F. (1978) Nature (Lond.) 273, 120-124] from position 259-387. This part of the polypeptide links and participates in all three domains of the flavoenzyme.
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PMID:Glutathione reductase from human erythrocytes. Amino-acid sequence of a major fragment that links the FAD, NADP and interface domains. 23 39

The subunit structure of rat liver acetyl-coenzyme-A carboxylase has been studied by polyacrylamide gel electrophoresis in the presence of dodecylsulfate. A number of individual preparations of the enzyme purified by the same procedures exhibited three different types of electrophoretic patterns as follows: first, a single slow-moving protein bands (Mr 230000); secondly, two adjacent fast-moving protein band (M4 124000 and 118 000); finally, all three protein bands. With the use of the [14C]biotin-labelled enzyme, the biotinyl prosthetic group was shown to be associated with the polypeptide of 230000 Mr as well as with that of 124000 Mr, but not with the polypeptide of 118000 Mr. Studies were next made with the labelled enzyme to examine the possibility that the two light polypeptides might have been formed by proteolytic modification of the heavy polypeptide during the procedures used for the purification of the enzyme. Treatment of the enzyme with trypsin or chymotrypsin resulted in cleavage of the heavy polypeptide into two nonidentical polypeptides with molecular weights of approximately 120000. Incubation of the enzyme with proteases derived from rat liver converted the heavy polypeptide into lighter polypeptides of 80000-130000 Mr. Acetyl-CoA carboxylase isolated from crude rat liver extracts by means of immunoprecipitation with specific antibody invariably showed only the heavy polypeptide. The biotin content of the enzyme was found to be 1 mol per 237000 g protein. These results indicate that rat liver acetyl-CoA carboxylase, unlike bacterial and plant biotin enzymes, has only one kind of subunit, which has a molecular weight of 230000 and contains one molecular of biotin. Thus, the mammalian enzyme exhibits a highly integrated subunit structure.
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PMID:Acetyl-coenzyme-A carboxylase from rat liver. Subunit structure and proteolytic modification. 24 Jul 17

A trypsin inhibitor isolated from a potato acetone powder has been purified by affinity chromatography. This protein inhibits trypsin mole per mole. To a lesser extent it combines also with chymotrypsin and elastase. For trypsin, K1 = 8 X 10(-7) M. The inhibitor has a single polypeptide chain of 207 amino acid residues. It contains no sugar or free sulfhydryl groups. Its extinction coefficient E2801% = 10.3 and its isoelectric point is 6.9. Its molecular weight is of the order of 21 000-22000, as determined by sedimentation equilbrium, by inhibition experiment or from its amino acid composition. These same techniques, taken together with the single band observed at different pH on polyacrylamide gel electrophoresis, indicate that the protein purified is monodisperse. However, the finding of two N-terminal amino acid residues, leucine and aspartic acid, and the different stoichometry observed during the interaction of the inhibitor, either with trypsin or with chymotrypsin and elastase, raises the possibility that our preparation is contaminated by a polyvalent inhibitor not detectable by physiochemical methods.
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PMID:Purification and characterization of a trypsin inhibitor from Solanum tuberosum. 24 76

Although the tripeptides Glu-O-Phosphoserine-Tyr and Glu-O-Phosphoserine-Leu have been identified in embryonic bovine enamel proteins, 1, 2 the issue of whether both sequences occur in each of the phosphopeptides, or whether certain sequences occur in specific peptides only, has recently been resolved by isolating homogeneous samples of E33 and E44. All three of the Ser residues of both peptides are phosphorylated. All three in E3 are in the sequence Glu-O-Phosphoserine-Leu, and all three in E4 are in the sequence Glu-O-Phosphoserine-Tyr. It was not possible to sequence either of the polypeptide chains directly by automatic peptide sequencing. However, a partial sequence of E4 was constructed from data derived from peptides isolated after cyanogen bromide, trypsin and chymotrypsin digestions. The presence of Glu, Tyr and Leu adjacent to and near the O-Phosphoserine [Ser(L)] residues and the 2 degrees, 3 degrees and higher ordered structures of the enamel phosphopeptides may be important in calcium binding and mineralization.
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PMID:Phosphopeptides of enamel matrix. 28 20

We have identified and purified a polypeptide region containing the collagen-binding site of the adhesive glycoprotein fibronectin. Chicken cellular fibronectin isolated from cultured embryonic fibroblasts was permitted to bind to gelatin coupled to agarose beads and was then digested extensively with chymotrypsin. A prominent 40,000-dalton fragment of fibronectin consisting of a single polypeptide chain was detected by sodium dodecyl sulfate/polyacrylamide gel electrophoresis of material remaining bound to the gelatin-agarose. This fragment appeared within 10 min after the digestion was initiated and persisted for more than 20 hr. This proteolytic fragment was isolated in electrophoretically pure form and retained its affinity for collagen. Plasma fibronectins from chicken and human blood also contained collagen-binding proteolytic fragments of similar size. This finding suggest that the collagen-binding sites of cellular and plasma fibronectins are homologous.
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PMID:Identification and isolation of a collagen-binding fragment of the adhesive glycoprotein fibronectin. 28 1

The biosynthesis in vivo of rat intestinal sucrase-isomaltase [a complex of sucrose alpha-glucohydrolase, EC 3.2.1.48, and oligo-1,6-glucosidase (dextrin 6-alpha-D-glucanohydrolase), EC 3.2.1.10] has been studied by following the incorporation of L-[6-(3)H]fucose into the enzyme with time. Immunoprecipitation of sucrase-isomaltase from Triton-X-100-solubilized Golgi or basolateral membranes and subsequent polyacrylamide gel electrophoresis revealed the presence of an immunoreactive glycoprotein with an apparent molecular weight approximately twice that of the separated sucrase-isomaltase subunits, but no active subunits were found in these membranes. This glycoprotein was also found in the microvillus membrane in addition to the subunits of sucrase-isomaltase. Kinetic studies showed a maximal labeling of this glycoprotein in Golgi membranes at 15 min, in basolateral membranes at 30 min, and in microvillus membranes at 45 min and a half-life of less than 30 min in each membrane. However, the radioactivity of the sucrase-isomaltase subunits in the microvillus membrane reached a plateau after 60 min. These data suggest that sucrase-isomaltase is synthesized as a one-chain polypeptide precursor that is split into the subunits after its transfer to the microvillus membrane. Elastase (EC 3.4.21.11), but not trypsin (EC 3.4.21.4) or alpha-chymotrypsin (EC 3.4.21.1), split the putative precursor into two polypeptides that had electrophoretic behaviors similar to those of the active enzyme subunits. These studies suggest that pancreatic proteases may play an important role in the late posttranslational processing of sucrase-isomaltase in vivo.
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PMID:Biogenesis of intestinal plasma membrane: posttranslational route and cleavage of sucrase-isomaltase. 29 33

Urogastrone is a potent inhibitor of gastric acid secretion which is present in human urine. Its existence has been known for over 30 years but it has only recently been isolated in a sufficiently pure form for detailed structural studies to be undertaken. Two separate polypeptides beta- and gamma-urogastrone were isolated. The structures were established by carrying out enzymic degradations of S-carboxymethyl and S-carboxamidomethyl derivatives with trypsin, chymotrypsin, thermolysin and a protease derived from the fungus Armillaria mellea. Sequences of the smaller peptides thus obtained were determined by the dansyl Edman method. Partial acid hydrolysis of urogastrone itself gave fragments containing single intact disulphide bonds, and oxidation then allowed the direction of individual bonds to be established. Beta-Urogastrone was shown to be a 53-amino acid residue polypeptide containing three disulphide bonds, and gamma-urogastrone had an identical sequence but lacked the C-terminal arginine residue. Urogastrone was subsequently found to be structurally related to mouse epidermal growth factor in that 37 of the 53 residues were commonly located in each polypeptide. Furthermore, as both peptides has similar effects upon gastric acid secretion and upon epidermal growth, urogastrone was also a human epidermal growth factor. The 16 variable residues were spread across the molecule, all apart from two were compatible with single base changes in the triplet condons, and the overall effect was to make uorgastrone more acidic than EGF. The smallest biologically active unit has not been defined but at least six residues can be removed from the C-terminus without causing a reduction in potency.
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PMID:The primary structure of human urogastrone. 30 79

The LAF produced by the mouse macrophage cell line, P388D1, is a single polypeptide chain of m.w. 12,000 to 16,000 daltons. Native LAF was destroyed by Streptomyces griseus protease, but not by trypsin, chymotrypsin, and papain, although in the presence of 8 M urea, papain completely destroyed LAF activity. LAF did not bind to concanavalin A-Sepharose, suggesting that LAF does not contain significant amounts of mannosyl or glycosyl residues. Since LAF activity was not inactivated by a treatment of reduction and alkylation the active conformation of LAF does not appear to be dependent on disulfide linkages. LAF was not irreversibly denatured by 8 M urea or 0.1 to 0.5% SDS. On SDS-polyacrylamide gels, the m.w. of LAF was 12,000 daltons, as compared to a value of 16,000 daltons, as determined by gel filtration. The isoelectric point of LAF was 5.0 to 5.4 as determined on 7.5% acrylamide gels (pH 3 to 10). On the basis of these results it appears that the P388D1 cell line-derived LAF is a relatively stable molecule that shares several physicochemical properties with normal human and mouse macrophage-derived LAF.
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PMID:Physicochemical characterization of lymphocyte-activating factor (LAF). 31 60

Poly(A)-containing mRNA isolated from the islets of Langerhans obtained from two species of fish, angler fish (Lophius americanus) and sea raven (Hemitripterus americanus), stimulated protein synthesis 16-fold in a wheat germ cell-free system. Characterization of the translation products by polyacrylamide gel electrophoresis in sodium dodecyl sulfate showed a major polypeptide weighing 11,500 daltons that was specifically precipitated by an antibody against angler fish insulin. Partial sequence analysis of the amino terminal revealed that this polypeptide is preproinsulin, in which the amino terminus of proinsulin is preceded by either 23 (angler fish) or 25 (sea raven) amino acid residues. Translation of fish islet mRNA in a wheat germ cell-free system in the presence of dog pancreas microsomal membranes led to the correct cleavage of the nascent preproinsulin, resulting in the synthesis of authentic fish proinsulin, as verified by partial sequence analysis. Moreover, the synthesized fish proinsulin was segregated, presumably into the luminal space of the dog pancreas microsomal vesicles, because it was found to be resistant to proteolysis by added trypsin and chymotrypsin. Our data thus suggest that the mechanisms and information for the transfer of secretory proteins across the microsomal membrane are highly conserved during evolution.
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PMID:Cell-free synthesis of fish preproinsulin, and processing by heterologous mammalian microsomal membranes. 32 65


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