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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)

Several fragments of bovine serum albumin have been isolated following limited tryptic hydrolysis and their positions then determined in the bovine serum albumin sequence published by J. R. Brown ((1975), Fed. Proc., Fed. Am. Soc. Exp. Biol. 34, 591). When bovine serum albumin was coupled to palmityl-aminoethylamino-agarose and digested with trypsin, two fragments were obtained: (a) peptide 115-184, containing the highly aromatic disulfide loop 3 of Brown's model, and (b) a larger fragment, residues 377-581, containing disulfide loops 7-9. This fragment constitutes the third of the three domains of the albumin molecule. From bovine serum albumin digested in solution, peptide 115-184 was again obtained, as well as (c) a 39,000-dalton fragment identified as residues 198-581, loops 4-9 of the second and third domains, but with a long, tryptophan-containing segment 204-238 missing from loop 4. The ability to isolate these fragments without cleaving disulfide bridges is partial confirmation of the proposed model of bovine serum albumin as a series of nine independent loops.
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PMID:Fragments of bovine serum albumin produced by limited proteolysis. Isolation and characterization of tryptic fragments. 109 43

Rat liver microsomes incubated with [3H] puromycin in high salt buffer were digested with a mixture of protease, trypsin and chymotrypsin, in both the presence and absence of 1 % deoxycholate. Our observations revealed that the proteolysis of peptidyl puromycin labeled with [3H] puromycin was at least partially protected by the presence of microsomal membrane. Immuno-chemical analyses have further shown that most of the nascent NADPH-cytochrome c reductase in the microsomes was digested with the proteases while serum albumin was effectively protected from the digestion. It is thus proposed that NADPH-cytochrome c reductase synthesized on the membrane bound ribosomes is not transported to the vesicular cavity but directly to the outer surface of the microsomal membrane in a form which is accessible to the proteases.
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PMID:Localization of nascent NADPH-cytochrome c reductase in rat liver microsomes. 111 86

1. 'Inhibitor fragment' isolated from human serum albumin degraded by rabbit cathepsin D is composed of one peptide chain with two intrachain disulphide bonds. There are two kinds of inhibitor molecules having different N-terminal amino acids: one is threonine and the other glutamine. 2. Fragment F1, isolated from inhibitor degraded by trypsin, is composed of two chains linked by a disulphide bond. There are three kinds of fragment F1. All have one alpha chain in common, which has an intrachain disulphide bond. They differ by the nature of the chain, which is linked to the alpha chain by a disulphide bond. The epsilon chain is present in trace amounts. The two other chains, beta and gamma, differ by their C-terminal amino acid, which is respectively arginine and lysine. 3. Inhibitor is composed of the last 92 or 89 residues of the human albumin molecule and fragment F1 is composed of two parts of this C-terminal portion of the albumin molecule.
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PMID:Chemical structure of two fragments of human serum albumin and their location in the albumin molecule. 116 60

Eight 1-(naphth-1-ylacetyl)-4-substituted thiosemicarbazides and eight 2-(naphth-1-ylmethyl)-5-arylamino-1,3,4-oxadiazoles were synthesized and evaluated for antiinflammatory and antiproteolytic properties. All thiosemicarbazides (100 mg/kg) provided 14-43% protection against carrageenin-induced edema in rats. Cyclization of thiosemicarbazides to oxadiazoles resulted in significant reduction in the antiinflammatory activity. Some of these thiosemicarbazides also possessed low antiinflammatory activity against cotton-pellet-induced granuloma formation and formaldehyde-induced arthritis in rats. Hydrocortisone and oxyphenbutazone, used as reference drugs, exhibited greater antiinflammatory activity. All compounds possessed antiproteolytic activity. The in vitro protection of trypsin-induced hydrolysis of bovine serum albumin, unlike antiinflammatory activity, was greater with oxadiazoles (30-90%) than the precursor thiosemicarbazides (4-50%) at a final concentration of 1 mM.
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PMID:Antiinflammatory and antiproteolytic properties of naphthlthiosemicarbazides and cyclized oxadiazoles. 117 29

The hydrophobic nature of proteins is characterized by a degree of 2-p-toluidinonaphthalene-6-sulphonate (TNS) affinity to them and is pronounced quantitatively in the semi-saturated (C1/2) concentrations. This index correlates directly with the position of TNS emission maximum after the binding with proteins and reversely with the yield of fluorescence. The preparations of phosphofructokinase, lactate dehydrogenase, xantinoxidase, glyceratekinase, lysozyme, RNase during the long (1-2 h) contact with TNS change the values C1/2, that evidences for interaction with the hydrophobic indicator of new structures of protein molecule or for a change in the nature of its linkage itself. An attempt is made to characterize the accessible for TNS hydrophobic nature of individual proteins by a coefficient of molar hydrophobic nature which unites three mentioned characteristics. Serum albumin, insulin, glucogon, alpha chemotrypsin, DNase are most hydrophobic, pyruvate kinase, aldolase, urease, RNase--least hydrophobic, Glycerate kinase, pyruvate decarboxylase, phosphofructokinase, lactate dehydrogenase, alcohol dehydrogenase, xanthinoxidase, trypsin, lysozyme are in intermediate position.
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PMID:[Comparative characteristics of hydrophobic nature of certain proteins by their interaction with 2-p-toluidinonaphthalene-6-sulfonates]. 120 4

1. The reactivity of alpha-chymotrypsin toward p-nitrophenylacetate has been studied in dimethylformamide, dimethylsulfoxide, formamide and methylacetamide. p-Nitrophenol is liberated in dimethylsulfoxide only. 2. The reactions of alpha-chymotrypsin in dimethylsulfoxide are characterized by the same kinetic and equilibrium constants with either the p-nitrophenyl esters of straight chain carboxylic acids (from acetic to n-caprylic) or with the "specific substrate", N-carbobenzoxy-DL-phenylalanine p-nitrophenyl ester. This signifies that reactions of alpha-chymotrypsin in dimethylsulfoxide, unlike those in aqueous medium, have no specificity toward su-strate structure. 3. The stoichiometry of alpha-chymotrypsin reactions in dimethylsulfoxide was shown to be about five moles of substrate per mole of enzyme. After attaining this stoichiometry, the reaction is completed. 4. Optical rotatory dispersion spectra indicate that in non-aqueous media alpha-chymotrypsin undergoes a large conformational transition which results in a random coil. 5. Chymotrypsinogen, trypsin, trysinogen, lysozyme and serum albumin react with p-nitrophenylacetate in dimethylsulfoxide at rates which are approximately equal to those of alpha-chymotrypsin. Thus, the "activity" of alpha-chymotrypsin in dimethylsulfoxide toward p-nitrophenylacetate does not differ from the "activity" of other proteins, some of which are not even hydrolytic enzymes.
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PMID:The reactions of alpha-chymotrypsin and related proteins with ester substrates in non-aqueous solvents. 120 14

Nuclear magnetic quadrupole relaxation appears to be a general method for studying the binding of anions to proteins. This is shown by the increase in transverse quadrupole relaxation rate of 35Cl- and 81Br- in the presence of horse liver alcohol dehydrogenase, lysozyme, trypsin, alpha-chymotrypsin, human carbonic anhydrase, fructose-1,6-bisphosphate aldolase and human serum albumin. Of the many possible binding sites at the surface of a protein (e.g. positively charged amino acid side-chains) only a few account for the main part of the relaxation enhancement. This is shown by the decrease in 35Cl- and 81Br- relaxation rate on addition of functional ligands. Large, kinetically inert, complex anions like Pt(CN)2-4 and Au(CN)-2 are found to act as strong competitors towards halogen ions for the high-affinity anion binding sites of a number of proteins. Titrations with complex anions following the 35Cl- or 81Br- relaxation rates are found to be helpful in attempts to elucidate binding mechanisms. Especially, the complex anions may be useful probes for the discrimination between general and metallic anion binding sites in proteins and they also permit correlation of information from X-ray investigations of crystals with that from physical measurements in solution. From the change in halide ion quadrupole relaxation rate on addition of strongly binding ligands the quadrupole coupling constants of the high affinity Cl- and Br- binding sites are estimated using certain assumptions. It is found that for several proteins, comprising the metal-free proteins but also alcohol dehydrogenase and Escherichia coli alkaline phosphatase, the 35Cl quadrupole coupling constants have approximately the same values. For some other metallo-proteins like carbonic anhydrase and a zinc - serum-albumin complex considerably greater quadrupole coupling constants were obtained. The estimated quadrupole coupling constants are used as a basis for a discussion of the interactions involved in anion-protein interactions.
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PMID:Pt(CN)2-4 and Au(CN)-2: potential general probes for anion-binding sites of proteins. 35Cl and 81Br nuclear-magnetic-resonance studies. 120 23

Trypsin hydrolyzates of blood serum albumin of healthy people and patients with diffuse thyrotoxicosis and hypothyreosis were studied by the cellulose thin-layer electrochromatography. All the patients were found to have changes in the peptide composition of albumin trypsin hydrolyzate which resulted in disappearance of some peptides as well as in the appearance of new ones. Simultaneously conducted measurements of dispersion of optical rotation detected some changes in spectropolarimetric characteristics which provide the evidence for disperalization of its molecule. The found changes in albumin are determined by the disorder of normal protein biosynthesis and possible metabolic damage of protein.
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PMID:[Study of peptide composition in serum albumin in patients with thyroid gland dysfunction]. 120 62

Role of peptide bond breaks in the incorporation of amino acids into proteins in a "protein--amino acid" system is investigated. For this purpose the incorporation of labelled amino acids into trypsin under the inhibition of its autolysis by a specific inhibitor from soybean and epsilon-amino-caproic acid is studied. The trypsin inhibitor from soybean is found to suppress considerably the incorporation of 14C-glycine, 14C-lysine and 14C-methionine into crystal trypsin and not to affect the incorporation of labelled amino acids into chomotrypsin, papain and carboxypeptidase. Epsilon-Aminocaproic acid inhibited 14C-glycine incorporation into crystal trypsin by 40% and did not change its incorporation level into serum albumin. The dependency of amino acid incorporation level into trypsin on the activity of autolysis in the "protein--amino acid" system is demonstrated.
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PMID:[Effect of proteolysis inhibitors on the incorporation of labelled amino acids into proteins]. 121 56

Some N,N'-bis(3-substituted benzylideneaminopropyl) piperazines were synthesized and characterized by their sharp melting points and elemental analyses. These substituted piperazines possessed anti-inflammatory activity, and the protection afforded by these compounds against carrageenan-induced edema ranged from 23 to 67%. The antiproteolytic activity of these piperazines was reflected by their ability to inhibit in vitro hydrolysis of bovine serum albumin and casein by trypsin. The inhibition of trypsin-induced hydrolysis was concentration dependent and competitive in nature.
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PMID:Synthesis of N,N'-bis(3-substituted benzylideneaminopropyl)-piperazines and their anti-inflammatory, antiproteolytic, and anticonvulsant properties. 126 90


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