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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The sedimentation of radiolabelled 22 nm hepatitis B surface antigen particles was unaffected by treatment with either trypsin or SDS alone, but combined treatment disrupted the particulate nature of the radiolabelled material. Considerable antibody binding activity by the group-specific determinant (a) was preserved after combined SDS and trypsin treatment but was released from the bulk of the radiolabelled protein; gel filtration indicated an approximate mol. wt. of 5000 to 15000 for the released antibody binding material. This material was precipitated by concanavalin A, suggesting the presence of carbohydrate. Its serological activity was remarkably resistant to boiling and to proteolytic digestion, but was partially sensitive to treatment with 0-01 M-periodate or with mixed carbohydrases and neuraminidase, and was greatly reduced by treatment with reducing agent. These data suggest that the stability of the a determinant is due to the structure of the antibody binding site itself, rather than to involvement in the quaternary structure of the particle, and that intact disulphide bonds and carbohydrate, closely related to the antibody binding site, are necessary for the full expression of serological acitivity.
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PMID:Tryptic cleavage of antibody binding sites from hepatitis B surface antigen particles. 6 23

SDS-polyacrylamide gel electrophoresis of a recently prepared alpha 2-macroglobulin solution showed only the polypeptide chains of 190,000 molecular weight. Reduction-alkylation of this preparation followed by gel-filtration on a Sephadex G-200 column in 5.2 M guanidine hydrochloride was unable to separate a fraction of 83,000 molecular weight as previously described. Nevertheless, after incubation of a mixture alpha 2-macroglobulin-trypsin during 45 minutes at 37 degrees C, approximately 60 per cent of the preparation were converted in a component with 83,000 molecular weight as detected in SDS polyacrylamide gel. That component was isolated on Sephadex G-200 in guanidine hydrochloride and corresponds to the subunit, fraction II. According to the results of the present work together with those of previous studies, it can be assumed that alpha 2-MG is a 780,000 molecular weight protein (19S) formed of two half-molecules of equal weight (11-12S). The half-molecule contains two polypeptide chains of 180,000-190,000 molecular weight, each of them having, in its middle, a specific region particularly susceptible to attack by proteases.
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PMID:Subunit structure of human alpha 2-macroglobulin (alpha 2-MG) with respect to its interaction with trypsin. 6 51

Functionally active guinea pig factor B was purified by a combination of chromatographic steps including Sephadex G-25, QAE A25, QAE A50, CM C50, and Sepharose 4B coupled with purified cobra venom factor. Purified factor B had a m.w. of 106,000 daltons and a single subunit structure. It was heat labile. After cleavage of native B with cobra venom factor coupled to Sepharose 4B in the presence of D, the resulting two fragments, the larger one (Bb) and the smaller one (Ba), were further purified. The m.w. of Bb and Ba was determined as 64,000 and 53,000 daltons, respectively, by SDS-PAGE. Neither of the fragments evoked a contraction of guinea pig ileum or histamine release from rat mast cells. Only the smaller fragment Ba (at a concentration of 120 nM) stimulated guinea pig peritoneal polymorphonuclear leukocytes to respond with increased movement. This activity as well as the antigenicity of Ba were heat stable, but were sensitive to trypsin digestion, whereas the antigenicity of Bb was heat labile.
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PMID:Fragments Ba and Bb derived from guinea pig factor B of the properdin system: purification, characterization, and biologic activities. 7 89

A comparative study of the dissociation into subunits of Porcine alpha2 M, either native or bound to trypsin (Tn), has been carried out in order to determine the modifications of the alpha2 M structure due to the formation of the Tn-alpha2 M complex. Analytical ultra-centrifugation at pH 3.5 shows that the dissociation is smaller when alpha 2 M is bound to trypsin. Electrophoresis in 4% polyacrylamide gels, in presence of 0.1% SDS, of alpha2 M and Tn-alpha2 M incubated in 1% SDS leads to the same conclusion; the enzyme must stabilize the quaternay structure of alpha2 M. In presence of SDS + beta-mercaptoethanol, only a molecular weight (M.W.) 200,000 band is revealed in electrophoresis pattern of native alpha2 M. In the case of reduced Tn-alpha2 M, some other bands of M.W. 100,000, 50,000, 30,000 appear. When trypsin is inactivated by TLCK 100,000 M.W. band is present, accompanied by the 200,000 M.W. band whose intensity is function of the alpha2 M concentration. The 100,000 M.W. band appears therefore characteristic of the formation of the complex which must imply a proteolytic cleavage in the middle of the 100,000 polypeptidic chain of alpha2 M. A model of the complex is proposed in which the enzyme forms a proteic bridge between the two halves of the alpha2 M molecule.
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PMID:[Model of the interaction between trypsin and alpha 2-macroglobulin of porcine serum]. 7 73

Monovalent antibody fragments are now recognized to have major advantages over intact immunoglobulin G in immunohistochemistry, but the methods commonly used for their preparation do not necessarily give a maximal yield of active antibody fragments and take little account of species differences. Sodium dodecyl sulphate (SDS) slab-gel electrophoresis demonstrated large differences in the susceptibility to digestion of antibodies of different species and was found to be valuable in the selection of optimal digestion conditions. Promising results were obtained with sheep antibodies by use of low concentrations of trypsin, and an immunoadsorbent technique showed a high yield of antibody fragments.
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PMID:Preparation of antibody fragments: conditions for proteolysis compared by SDS slab-gel electrophoresis and quantitation of antibody yield. 9 49

A trypsin-like oviducal proteinase acting upon the vitelline envelope of Bufo arenarum coelomic oocytes has been purified to apparent homogeneity by gel filtration on Sephadex G-200 and by affinity chromatography on a column of Sepharose 4-B containing covalently bound concanavlin A (Con A). The biologically active molecule migrated as a single band of protein upon SDS polyacrylamide gel electrophoresis.
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PMID:An oviducal enzyme isolated by affinity chromatography which acts upon the vitelline envelope of Bufo arenarum coelomic oocytes. 9 76

In the outer membrane of P. aeruginosa, a protein of apparent molecular weight 8,000 (protein I) is present as a major protein. Purification and chemical analysis of protein I were carried out. This protein was purified by essentially the same procedure as for the purification of the E. coli lipoprotein, which was developed by Inouye et al. (J. Bacteriol. (1976) 127, 555--563). The amino acid composition of protein I was determined. Protein I lacks proline, valine, isoleucine, phenylalanine, tryptophan, and half-cystine. Fatty acid analysis of the protein revealed that it contained 0.89 mol of fatty acids per mol of protein. Among the fatty acids hexadecanoic acid (C16:0) was predominant. In an in vivo labeling experiment, [2-3H]glycerol was incorporated into protein I. A protein with similar mobility to protein I on urea-SDS polyacrylamide gel electrophoresis was isolated from the purified peptidoglycan of P. aeruginosa by trypsin digestion. The amino acid composition of this protein was essentially the same as that of protein I. These results indicate that the outer membrane of P. aeruginosa contains a protein analogous to the E. coli lipoprotein, although considerable differences were observed in the amino acid composition and the fatty acid content.
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PMID:Isolation of characterization of a major outer membrane protein of Pseudomonas aeruginosa. Evidence for the occurrence of a lipoprotein. 10 84

Pseudomonas aeruginosa strain P15 produces not only pyocin R1 and phage PS10, but also a substance having a flexuous rod structure, the nature of which is so far unknown. A variant strain (P15--40) was obtained which produced these flexuous particles more effectively than the original strain, and the particles were purified to homogeneity and investigated. Several strains of P. aeruginosa were found to be killed by the particles. It was concluded that the flexuous rod-like particles are not related to pyocin R1 or phage PS10, but represent a new pyocin, which we have designated as pyocin F1. Pyocin F1 showed a different action spectrum and a different pattern on SDS-polyacrylamide gel electrophoresis from either pyocin R1 or phage PS10. The killing activity of pyocin F1 was of single-hit type. The activity was not affected by anti-R1, anti-R1-core or anti-PS10, or by DNase, RNase, pronase or trypsin, but was completely destroyed by treatment at 70 degrees C for 10 min. Some cofactor was required for the adsorption of this pyocin on sensitive bacteria. Another flexuous bacteriocin was also found and named pyocin F2.
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PMID:Biochemical properties of a new flexuous bacteriocin, pyocin F1, produced by Pseudomonas aeruginosa. 10 91

The present study indicates that crystalline elastase of Pseudomonas aeruginosa is a very potent inactivator of human plasma alpha 1-proteinase inhibitor, the enzyme (E) inactivated the inhibitor (I) almost completely within 1 h at 25 degrees C at a molar ratio of E/I = 1:100. The crystalline P. aeruginosa protease also inactivated the inhibitor, but 100-fold less. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the alpha 1-proteinase inhibitor inactivated by the elastase and protease showed decreases in molecular weight of approximately 5,000 and 10,000, respectively. Regeneration of trypsin was negligible even when bovine trypsin-alpha 1-proteinase inhibitor complex (E/I = 1.0) was treated with the elastase. The affinity of alpha 1-proteinase inhibitor to trypsin was much higher than that to elastase. It was suggested that, assuming the pseudomonal proteases are produced and can inactivate alpha 1-proteinase inhibitor in vivo during pseudomonal diseases, the loss of alpha 1-proteinase inhibitor activity may permit the endogenous serine proteases to cause tissue destruction.
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PMID:Protease and elastase of Pseudomonas aeruginosa: inactivation of human plasma alpha 1-proteinase inhibitor. 11 Jun 91

The variations of proteins and glycoproteins of Chick embryo fibroblasts are studied during development. This investigation is carried out using polyacrylamide disc gel electrophoresis in SDS. Two glycoproteins of high apparent molecular weight (250,000 and 200,000) undergo quantitative modification: they increase from the 8th to 12th day of development and then remain unchanged to the 16th day. They are cell surface components as suggested by fluorescamine labelling and trypsin sensitivity. The results are discussed in terms of relationship between tumor- and embryo cells.
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PMID:[Electrophoretic profiles of proteins and glycoproteins of chick embryo fibroblasts during development]. 11 22


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