Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cleavage of the two methionine residues in the glycoprotein trypsin inhibitor ovomucoid, variant O1, with CNBr resulted in two fragments whose mol.wts. were approx. 16 600 (fragment LS) and 11 000 (fragment M). Both fragments formed precipitates with antisera to ovomucoid. Fragment LS retained 56% of the trypsin-inhibitory activity of ovomucoid, but fragment M did not inhibit. After reduction and alkylation, the molecular weight of fragment M was unchanged, but fragment LS could be resolved into two segments of peptide chain with mol.wts. of approx. 12000 (fragment L) and 4700 (fragment S). Each of these peptides contained carbohydrate. Marked heterogeneity was observed in the hexose and hexosamine contents of fragment L. This may account for much of the heterogeneity in neutral carbohydrate occurring in ovomucoid preparations. It was found that fragment M was located at the N-terminal end, fragment S was in the centre and fragment L made up the C-terminal portion of the molecule.
 ...
PMID:Active fragments obtained by cyanogen bromide cleavage of ovomucoid. 93 85

The complete primary structure of the major component myoglobin from the California gray whale, Eschrichtius gibbosus, was determined by specific cleavage of the protein to obtain large peptides for degradation by the automatic sequenator. Cleavage at the two methionine residues of the apomyoglobin with cyanogen bromide and at the three arginine residues of the methyl acetimidated protein with trypsin resulted in three and four easily separable peptides, respectively, which when sequenced accounted for 85% of the primary structure. The remainder of the covalent structure was obtained by further digestion of the central cyanogen bromide peptide with trypsin and S. aureus strain V8 protease. This protein differs from that of the sperm whale, Physeter catodon, at 12 positions, from that of the common porpoise, Phocoena phocoena, and the Black Sea dolphin, Delphinus delphis, at 14 positions, and from that of the Amazon River dolphin, Inia geoffrensis, at 7 positions. All substitutions observed in this sequence fit easily into the tertiary structure of sperm whale myoglobin.
 ...
PMID:Complete primary structure of the major component myoglobin of California gray whale (Eschrichtius gibbosus). 93 29

The homology of Subunit III of bovine procarboxypeptidase A-S6 (EC 3.4.12.-) with Subunit II (bovine chymotrypsinogen C) of the same complex, already reported in a previous publication (Puigserver, A. and Desnuelle, P. (1975) Proc. Natl. Acad. Sci. U.S. 72, 2442-2445) has been extended to the position of the single methionine of the chains. The sequence linked by 4 disulfide bridges out of 5 are also probably homologous in the 2 proteins. The last bridge is displaced in Subunit III as a consequence of the deletion of the N-terminal half-cystine. Subunit II, which is not activatable by trypsin, due to the loss of essential residues in the N-terminal region, has conserved a weakly functional active site reacting with concentrated diisopropylfluorophosphate at exactly the same rate as that of Subunit II.
 ...
PMID:Further characterization of subunit III of bovine procarboxypeptidase A-S6 as a non activatable zymogen. 95 43

Three methionine-modified derivatives of ovine prolactin have been prepared: two by oxidation of the methionines by H2O2 to sulfoxide (partial and complete), and the third by complete alkylation of the metionines with iodoacetic acid to the carboxymethyl sulfonium salts. The derivatives were characterized by exclusion chromatography, amino acid composition, circular dichroism spectra, relative rates of digestion by trypsin, and biological activity. Partially oxidized prolactin, having four of its seven methionines oxidized, was very similar to the native hormone. The unmodified methionines in partially oxidized prolactin were found to be the residues at positions 36, 81 and 132. The prolactin derivatives in which all the methionines had been oxidized, or alkylated, showed major changes in all parameters examined. In addition, circular dichroism spectra indicated that complete modification of all the methionines in prolactin exposes the normally buried tryptophans.
 ...
PMID:Studies on pituitary prolactin. 39. Reaction of the ovine hormone with hydrogen peroxide. 95 54

A tRNA activator has been isolated from mammalian organs which increases the capability of tRNA to accept certain amino acids through the action of mammalian aminoacyl-tRNA synthetases. This activity may be separated from the aminoacyl-tRNA synthetases for isoleucine, lysine, serine, and methionine by fractionation of liver or pancreas cytosol with ammonium sulfate or by chromatography over Sephadex G-200. The tRNA activating material is nondialyzable and is destroyed by trypsin or short heating. It acts catalytically. A molecular weight of approximately 45,000 was obtained by chromatography of tRNA activator on a calibrated Sephadex G-150 column. Activator increases acceptance of yeast tRNA for the amino acids isoleucine, leucine, lysine, serine, and methionine. It shows higher activity on liver tRNAMet f, tRNAMet m, and tRNALys than on unfractionated liver tRNA. Removal of protein from mammalian tRNA by extra phenol extractions, chromatography, or proteinase treatment increases its response to activator.
 ...
PMID:Catalytic activation of transfer ribonucleic acid by a mammalian protein. 96 9

1. The preliminary phytochemical screening of the two seeds established the presence of carbohydrates and/or glycosides, flavnoids, unsaturated sterols and/or triterpenes, saponins, trypsin inhibitors and haemagglutinins. In addition, it established the absence of cardenolides, tannins, alkaloids and oxidase enzyme. 2. Certain pharmacopoeial constants, including moisture, ash, acid-insoluble ash, water-soluble ash and crude fibre were determined. 3. The two seeds were subjected to successive extractions with different organic solvents such as petroleum ether (50-70 degrees C), diethyl ether, chloroform and ethyl alcohol. The successive yields of extractives were determined. Examination of the crude extracts showed that petroleum ether extract contained sterols and/or triterpenes, while ether, chloroform, and ethyl alcohol extracts contained reducing substances. 4. General analysis of the two seeds for proteins, fats, carbohydrates, fibre and ash contents were carried out and the results were given in g/100 g dry seeds. Pigeon pea contained 25.2 g protein, 170 mg calcium and 8.9 mg iron. The protein content of kidney bean was 23 g, while calcium and iron contents were 134 mg and 8.02 mg respectively. 5. Extractions of the proteins using different solvents such as cold water, hot water, saline buffer pH 7 and sodium hydroxide was the best extractant. 6. The amino-acid content of the two seeds, whether raw or cooked, showed that they were deficient in methionine, cystine and tryptophan. Other essential amino acids were present in amounts higher than that given by the FAO provisional pattern. 7. Cooking the seeds by the popular methods used in the country resulted in an increase in the amounts of the amino acids, threonine, leucine and isoleucine, while the other amino acids present remained unchanged or decreased. It was also observed that cooking the seeds destroyed the trypsin inhibitors and haemagglutinins found in the two seeds.
 ...
PMID:Phytochemical and nutritional studies on pigeon pea and kidney bean cultivated in Egypt. 96 10

The complete amino acid sequence of the major component myoglobin from the Atlantic bottlenosed dolphin, Tursiops truncatus, was determined by specific cleavage of the protein to obtain large peptides that are readily degraded by the automatic sequencer. Three easily separable peptides were obtained by cleaving the protein with cyanogen bromide at the 2 methionine residues and 4 peptides were obtained by cleaving the methyl acetimidated protein with trypsin at the 3 arginine residues. By subjecting 4 of these peptides and the apomyoglobin to automatic Edman degradation, over 80% of the covalent structure of the protein was obtained. The remainder of the primary structure was determined by further digestion of the central cyanogen bromide peptide with trypsin and staphylococcal protease. This myoglobin differs from that of the sperm whale, Physter catodon, at 15 positions, from that of the California gray whale, Eschrichtius gibbosus, at 14 positions, from that of the common porpoise, Phocoena phocoena, at 6 positions, and from the myoglobin of the Black Sea dolphin, Delphinus delphis and the Amazon River dolphin, Inia goeffrensis, at 5 and 7 positions, respecitvely. All substitutions observed in this sequence fit easily into the tertiary structure of sperm whale myoglobin.
 ...
PMID:Complete amino acid sequence of the myoglobin from the Atlantic bottlenosed dolphin, Tursiops truncatus. 97 68

The enzymic hydrolysis of some proteins (insulin-B-chain-S-sulfonate, S-aminoethylated lysozyme, bovine serum albumin) by immobilized peptidolytic enzymes is reported. Sepharose-bound pronase, trypsin and a protease from Thermoactinomyces sp. (MP), the latter both cross linked by glutaric dialdehyde and an exopeptidase mixture containing Sepharose-bound leucine aminopeptidase, carboxypeptidase A and a crude preparation of prolidase were used. After enzymic hydrolysis nearly all amino acids, except proline, were recovered in a 100% yield compared to the value of an acid reference hydrolysate. Tryptophan and methionine, which are partially destroyed by acid hydrolysis in the presence of oxygen could be recovered completely.
 ...
PMID:[Protein hydrolysis by immobilized enzymes]. 98 21

Activities of hydrolytic enzymes on the surface of monkey kidney, canine kidney, L. FM3A and various tumor cells were determined and compared with those in the cell homogenate. Although aminopeptidase (EC 3.4.11.-) activities were always detected on the surface membrane in mammalian cells, trypsin, chymotrypsin and elastase activities were not detected while slight glycosidase activity was detected in a suspension of cultured cells. The activities of alanine-, leucine-, methionine- and phenylalanine-aminopeptidases were rather high but aminopeptidase A, proline-, valine-, glycyl propline dipeptidyl-and glycyl propyl leucine-tripeptidyl-aminopeptidases showed relatively low activities. Aminopeptidase activity was also demonstrated in the isolated membrane fractions. The specific activities of enzymes in these membrane fractions were not significantly greater than in cell homogenate so it was concluded that these enzyme activities were rather loosely bound to the cell membrane. Further evidence for the localization of the aminopeptidase activities on the cell surface was obtained by using glass-bead-bound substrate and detecting the release of the terminal residues. When bestatin, a specific inhibitor against aminopeptidase B and leucine aminopeptidase, was included in the assay system for the enzyme activities on the cell surface, the enzymes were commonly inhibited in all types of cells.
 ...
PMID:Aminopeptidase activities on the surface of mammalian cells. 99 Mar 9

Fourteen 3-carboxypropionyl-tripeptide-p-nitroanilides of the general formula 3-carboxypropionyl-alanyl-alanyl-Y-p-nitroanilide (Y = glycine, norvaline, S-methylcysteine, valine, norleucine, S-ethylcysteine, methionine, leucine, isoleucine, phenylalanine, tyrosine, S-benzylcysteine, Calpha-phenylglycine, and proline) were synthesized and their cleavage by elastase, trypsin, and chymotrypsin (Km, kcat and kcat/Km) was determined. The significance of amino acid residues in the position of Y was evaluated firstly with respect to their structure (topographically), and secondly with respect to their free energy (thermodynamically). The alanine residue substrate was cleaved best by elastase, the phenylalanine substrate by chymotrypsin. Trypsin cleaved two substrates only, that is those containing a phenylalanine and a tyrosine residue. The optimum length of the elastolytic substrates was studied in a series of N-3-carboxypropionyl-(Ala)n-p-nitroanilides (n = 1, 2, 3, 4, 5), N-3-carboxypropionyl-(Gly)n-p-nitroanilides (n = 1, 2, 3), and in p-nitroanilides of fatty acids with two to seven carbon atoms. Elastase cleaved tri, tetra, and pentapeptides of alanine. p-Nitroanilides of the glycine series, as well as p-nitroanilides of fatty acids were not cleaved. 3-Carboxypropionyl-tetra-alanine-p-nitroanilide was the most suitable substrate so far found for elastase cleavage; it is not cleaved by trypsin nor chymotrypsin. The optimum distance between Y and the terminal anionic carboxyl residue was found to be 1.8 nm in elastolytic substrates.
 ...
PMID:p-Nitroanilides of 3-carboxypropionyl-peptides. Their cleavage by elastase, trypsin, and chymotrypsin. 99 49


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>