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)

From a crude extract of chick peas (Cicer arietinum L.) inhibitors of trypsin and chymotrypsin were isolated by affinity chromatography on a column of trypsin-Sepharose 6B. The content of inhibitors was found to be 1.5 g/kg. They were further separated into six isoinhibitors by ion-exchange chromatography on DEAE-Sephadex A-25. Two of the isoinhibitors accounted for about 50% of the isolated inhibitors and were further purified to a homogeneous state. The isoinhibitors had a molecular weight of about 10000 as determined by molecular-sieve chromatography on Sephadex G-75. They were stable towards extremes of pH and temperatures up to 75 degrees C or towards digestion by pepsin. They were also stable in 6 M urea but not in 6 M guanidine-HCl. The intact inhibitors were destroyed when the peas were cooked at 100 degrees C or when they were toasted at 130 degrees C. The four major inhibitors had similar amino acid compositions and did not contain detectable amounts of free sulfhydryl groups, tryptophan or carbohydrate. Cysteine is the dominant amino acid residue in all of them and accounted for about 20% of their amino acid content. The isoelectric point of the isoinhibitors lies in the range of pH 4.9-8.6 and two of the major inhibitors had isoelectric points of pH 4.75 and pH 4.96. They inhibited chymotrypsin to the same extent but differed in their inhibitory activities towards trypsin, indicating that they are mixtures of native and trypsinmodified forms and that they probably have separate sites for the two enzymes. They did not inhibit other proteolytic enzymes belonging to two groups (i.e., serine or cysteine enzymes) or originating from different sources (i.e., animals, plants or bacteria).
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PMID:The trypsin and chymotrypsin inhibitors in chick peas (Cicer arietinum L.). Purification and properties of the inhibitors. 0 Dec 66

An absorbent for the affinity chromatography of trypsin [EC 3.4.21.4] (AP Sepharose) was prepared. The ligand was a mixture of oligopeptides (mainly di- and tripeptides) containing L-arginine as carboxyl termini, and was obtained from a tryptic digest of protamine. Trypsin was absorbed at relatively low pH (7-4), but was not absorbed at the optimum pH of catalysis (8.2). This was clearly explained on the basis of the pH dependence of the interaction of trypsin with its products. Inactivated trypsin, trypsinogen, and chymotrypsin were not absorbed. The absorption of active trypsin was interferred with by either benzamidine or urea. From these observations, it is evident that AP Sepharose is an affinity adsorbent. AP Sepharose was useful for purification of commercial bovine trypsin. A preliminary application for the purification of Streptomyces griseus trypsin was also successful.
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PMID:Affinity chromatography of trypsin and related enzymes. I. Preparation and characteristics of an affinity adsorbent containing tryptic peptides from protamine as ligands. 0 82

The chemical modification of two new double-headed-protease inhibitors from black-eyed peas, a trypsin-chymotrypsin inhibitor (BEPCI) and a trypsin inhibitor (BEPTI) with dansyl chloride was investigated under various conditions. The NH2-terminal serine of both BEPCI and BEPTI, the 4 lysyl residues of BEPCI, and 4 of the 5 lysyl residues of BEPTI, could not be dansylated in the absence of urea. The single tyrosine per subunit of BEPCI and BEPTI was unreactive even in the presence of urea but could be labeled with half-site reactivity by the Celite method. Lysine, NH2-terminal serine, and tyrosine were reactive in fully reduced, carbamidomethylated BEPCI and BEPTI. Gel filtration was used to study the subunit interactions of BEPCI and BEPTI. At pH 8 or pH 3.0 there is a complex set of multiple equilibria with widely differing rates of attainment. We have found evidence for a rapid dimer-tetramer equilibrium, a distinct moderate rate dimer-tetramer equilibrium, a very slow monomer-dimer equilibrium, and postulate slow isomerization of the two forms of dimer and the two forms of tetramer. The monomer-dimer equilibrium is quite unusual in that the dimer is stabilized by chaotropic ions and even slightly by guanidine HC1. In contrast to the complex pattern seen in native BEPCI, the half-site, dansylated BEPCI exists at similar concentration exclusively as a tetramer at neutral pH.
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PMID:Double-headed protease inhibitors from black-eyed peas. III. Subunit interactions of the native and half-site chemically modified proteins. 0 94

Two proteinases (2A and 2B) purified from the granular fraction of horse blood leucocytes degrade casein (Km values 12.8 and 6mg/ml respectively) with maximum activity at pH 7.4 and in the presence of 2m-urea. Urea-denatured haemoglobin, fibrinogen, albumin and resorcin/fuchsin-stained elastin are digested at a slower rate. The enzymes hydrolyse synthetic substrates of elastase, N-benzyloxycarbonyl-L-alanine 4-nitrophenyl ester (Km 0.114 and 0.178 mM) and N-acetyl-tri-L-alanine methyl ester (Km 5.55 and 0.98 mM), but they do not hydrolyse synthetic substrates of trypsin, chymotrypsin and thrombin. The examined proteinases are completely inhibited by 2 mM-di-isopropyl phosphorfluoridate and show a sensitivity to butyl and octyl isocyanates similar to that of pancreatic elastase. The pH-dependence of their photoinactivation in the presence of Rose Bengal indicates the presence of histidine in the active centre. Proteinase 2A rather insensitive to iodination by IC1 as is pancreatic elastase, whereas proteinase 2B is totally inactivated after incorporation of five iodine atoms per enzyme molecule.
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PMID:Substrate specificity and modifications of the active centre of elastase-like neutral proteinases from horse blood leucocytes. 0 9

Plasma membrane preparations from KA31 (mouse) cells contained receptors for the binding of Rauscher murine leukemia virus (R-MuLV) envelope glycoprotein, gp70. This binding was demonstrated by gel filtration of a mixture of the microsomal fraction of the cells and 125I-labeled gp70. A rapid and convenient assay was developed to measure the complex formation between the membrane receptors and gp70 involving specific precipitation of the complex by 3 to 4% polyethylene glycol. The complex formation was responsive to the concentrations of both the receptor and gp70 and also to changes in temperature and pH. The gp70 binding was a noncooperative, saturable process, and an association constant of 3.5 X 10(8) M-1 was estimated from the binding data. The complex formation was reversible and a near-total exchange of 125I-labeled gp70 in the complex was achieved by incubation with excess of unlabeled gp70. The complex formation was inhibited by protein denaturing agents, guanidine-hydrochloride and urea. Pretreatment of the membrane fractions with either chymotrypsin or phospholipase C led to a loss of the membrane-associated receptor activity, indicating that a lipoprotein structure was important for the receptor function, consistent with the observation that nonionic detergents strongly inhibited the complex formation.
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PMID:Characterization of Rauscher murine leukemia virus envelope glycoprotein receptor in membranes from murine fibroblasts. 3 3

During the process of cultivation of Th. vulgaris several proteases are formed. In the present investigation the extensively purified major component was used. The substrate specificity was determined by means of 7 proteins, 7 amino acid esters, 5 fatty acid esters and 15 amino acid 4-nitroanilides. Among the protein substrates tested, urea denaturated hemoglobin was split best, followed by gelatin, casein, field bean protein, serum albumin and gluten. The weakest rate of hydrolysis was observed with elastin. In contrast to this acetyl-(L-ala)3-methylester, that is a substrate for elastase, was split best from all the esters tested. Only 8% of this activity could be found with the chymotrypsin substrates acetyl-L-tyr-ethylester and acetyl-L-phe-ethylester and 1% of the above activity with the trypsin substrates tosyl-L-arg-methylester and benzoyl-L-arg-methylester. The fatty acid esters and the p-nitroanilides were hydrolyzed much more slowly. The pH-optimum of thermitase was found in the weakly alkaline region of pH 7 to 9. There were only small differences between the individual high and low molecular substrates. The temperature optimum was between 60 and 75 degrees C for esters and p-nitroanilides as substrates and at 90 degrees C for casein. It should be mentioned that the enzyme was quickly inactivated at temperatures above 70 degrees C.
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PMID:[Characterization of a protease from Thermoactinomyces vulgaris (thermitase). 3. Substrate specificity and properties of partially purified thermitase]. 3 57

Alpha2-M (alpha2-macroglobulin) was purified from human plasma by two different procedures. As well as having no detectable impurities by the usual criteria for testing the homogeneity of protein preparations, these alpha2M preparations showed a single component, after reduction in urea, of 185000 daltons by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The molecular weight of the alpha2M was found to be 718000 by sedimentation equilibrium experiments using the gravimetrically determined -v of 0.731 ml/g. The interaction of several proteinases with alpha2M was studied by using a novel discontinuous polyacrylamide-gel system, which showed clear separation of the enzyme-complexed alpha2M from the free alpha2M. These studies indicated that urokinase, as well as trypsin, chymotrypsin, plasmin and thrombin forms complexes with alphaM. The cleavage of the 185000-dalton subunit to a 85000-dalton species on interaction of trypsin with alpha2M was demonstrated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis after reduction of the alpha2M-trypsin complex in urea. The amino acid composition, carbohydrate content, absorption coefficient at 280 nm, the specific refractive increment and the sedimentation coefficient for these alpha2M preparations were measured. The stability of the trypsin-binding activity of the alpha2M preparations was also studied under several storage situations.
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PMID:Physical and chemical properties of human plasma alpha2-macroglobulin. 8 Feb 17

The recently described triplet probe depolarization technique has been utilized to investigated the rotational relaxation of free and protease-bound alpha2-macroglobulin. The molecular Stokes radius of the free globulin was found to be 88 A, a value which, when compared to the dry radius, indicates a high degree of hydration. The correlation time of alpha2-macroglobulin does not change after its binding with chymotrypsin, but slightly increases in the presence of plasmin. In the presence of 4 M urea, alpha2-macroglobulin dissociates into subunits and this dissociation does not lead to a release of the bound proteases.
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PMID:Rotational relaxation of free and protease-bound alpha2-macroglobulin. 8 Dec 4

The physical, chemical, and immunologic properties of a protease from rat skeletal muscle, proposed to function in the degradation of certain intracellular enzymes, are identical to those of a chymotrypsin-like serine protease isolated from peritoneal mast cells. The results of polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and 8 M urea indicate that the two rat proteases have identical mobilities corresponding to a molecular weight of 26,000. The relative amino acid compositions of the proteases are nearly identical. Immunodiffusion tests for crossreaction between the muscle protease and antisera directed toward mast cell protease indicate that the former is immunologically identical to mast cell protease. The first 35 amino-terminal residues of the two enzymes are identical and indicate homology of these proteins to other mammalian serine proteases. The sequence analysis of the protease from muscle was extended for an additional 16 positions, and comparison of this amino-terminal sequence with that of a similar enzyme from small intestine showed approximately 75% sequence identity. In contrast, only 40% of the residues in this region of bovine chymotrypsin A were found at corresponding loci in rat muscle protease. It is concluded that the protease from muscle or mast cells is closely related to the enzyme from small intestine which recently was localized in the "atypical" mast cells of gut mucosa [Woodbury, R. G., Gruzenski, G. M. & Lagunoff, D. (1978) Proc. Natl. Acad. Sci. USA 75, 2785-2789].
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PMID:A major serine protease in rat skeletal muscle: evidence for its mast cell origin. 10 93

Flounder muscle (Pseudopleuronectes americanus) glyceraldehyde-3-phosphate dehydrogenase was characterized as to its stability towards various inactivating treatments in the presence and absence of the enzyme cofactor, NAD. Incubation of a partially purified enzyme preparation at urea concentrations greater than 2 M produced a very rapid inactivation. NAD greatly reduced the rate of inactivation at all the urea concentrations tested. Incubation of each of the three major muscle enzyme forms in 0.1 percent trypsin or chymotrypsin for forty-five minutes decreased the activity of each form by 65 percent and 55 percent, respectively. NAD (5mM) afforded complete protection to each enzyme form from proteolytic digestion by these two enzymes. Exposure of each form to 50 degrees or 20 mM ATP also led to gross inactivation which could be greatly reduced if the respective incubations were performed in the presence of 5mM NAD. NAD was also found to be required for the renaturation of the unfolded urea-denatured subunits to form the active tetramer.
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PMID:Effect of NAD on flounder muscle glyceraldehyde 3-phosphate dehydrogenase. 17 55


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