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)

Studied was the effect of some physical and chemical factors--heating, acidity, treatment with ultraviolet rays, and enzyme treatment--on the activity of the Brucella abortus 99 cell wall antigen. The activity of the antigen was determined through the microreaction of complement-fixing after Kolmer. It was found that the antigen was most sensitive to acid treatment and treatment with ultraviolet rays, and was more slightly sensitive to the effect of alkaline agents and pronase. Besides, the antigen proved heat-resistant and did not lose its activity after treatment with trypsin and alph- and beta-amylase. The chemical nature of the epitopes (the determinant groups), substantiating the activity of the antigen is briefly discussed.
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PMID:[Effect of physical and chemical factors on the antigenic activity of the cell walls of Brucella abortus 99]. 3 83

The sodium dodecyl sulfate (SDS) extraction-trypsin digestion protocol used by Braun and Sieglin (V. Braun and U. Sieglin, Eur. J. Biochem. 13:336-346, 1970) to show the peptidoglycan-linked lipoprotein of Escherichia coli was applied to both Brucella abortus and E. coli. Whereas a single polypeptide of 8,000 molecular weight was obtained from E. coli, several proteins of apparent molecular weight lower than 35,000 were demonstrated by SDS-polyacrylamide gel electrophoresis in B. abortus. These results did not change when the trypsin digestion conditions were modified. On the other hand, when the SDS extractions were performed under conditions more stringent than those used for other gram-negative bacteria, only a polypeptide fragment of apparent molecular weight of 8,000 was obtained from B. abortus. This polypeptide was similar to the trypsin fragment of the E. coli lipoprotein with respect to its behavior in SDS-polyacrylamide gels, isoelectric point in urea, molecular weight, and presence of both ester- and amide-linked fatty acids. Moreover, the amino acid analysis showed an overall similarity with respect to the amino acid composition of E. coli lipoprotein. A polypeptide of the same molecular weight, isoelectric point, and amino acid composition was also obtained from Brucella ovis by the same method. These results demonstrated that B. abortus and B. ovis cell envelopes contain a lipoprotein and strongly support the hypothesis that it is the only major protein covalently linked to the peptidoglycan.
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PMID:Demonstration of a peptidoglycan-linked lipoprotein and characterization of its trypsin fragment in the outer membrane of Brucella spp. 374 59

Purified human C3 was found to inhibit rat in vitro secondary antibody responses. Fifty percent inhibition of antibody-forming cell development occurred with C3 concentrations of 26 micrograms/ml. This decrease was not the result of a general toxicity or a shift in the antibody response kinetics. Using cell mixing experiments, we could not detect a C3-induced suppressor lymphocyte or macrophage. C3 was active when added to culture early (day 0 or 1 or during a 24-hr antigen prepulse) or late (day 3, 5, or 7)--the early addition being more suppressive. Regardless of the addition time, there was a characteristic 48- to 72-hr lag before the inhibitory effect was manifested. C3 could inhibit antibody-forming cell development after stimulation with the thymus-independent antigens, trinitrophenyl-Brucella abortus and dinitrophenyl-Ficoll, as well as the thymus-dependent antigens, dinitrophenyl-bovine gamma-globulin and chicken gamma-globulin suggesting that C3 was not selective for B memory cell subpopulations. Further characterization of our C3 preparation indicated that the majority of the suppressive activity resided in a small m.w. protein resembling the C3a fragment of C3. Human C3a preparations generated either by trypsin cleavage or zymosan activation of C3 were also tested in our antibody response system and were able to inhibit antibody-forming cell development. These data implicate C3 cleavage products as negative regulators of antibody formation.
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PMID:Inhibition of secondary in vitro antibody responses by the third component of complement. 646 62

A putative serine protease expressed in vivo by Mycobacterium avium subsp. paratuberculosis was isolated from a lambda gt11 genomic expression library by screening with serum from a naturally infected sheep. The gene was contained in two overlapping clones, which were shown by antibody elution to encode a protein of 34 kDa in M. a. paratuberculosis. The clones were sequenced and database searches detected a motif identical to the active serine site in trypsin, and 30% homology to the putative serine proteases (HtrA proteins) of Escherichia coli, Salmonella typhimurium, Brucella abortus and Rochalimaea henselae.
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PMID:Identification and characterization of a putative serine protease expressed in vivo by Mycobacterium avium subsp. paratuberculosis. 792 Dec 48

Brucella (B.) species lack classical virulence factors, but escape effectively the immune response of the host. The species Brucella abortus and Brucella melitensis infect predominantly cattle and small ruminants such as sheep or goats, respectively, but account also for most human cases. These two species share remarkably similar genomes but different proteomes have been demonstrated. This might be one of the reasons for their host specificity. A comprehensive identification of immunodominant proteins of these two species using antibodies present in the serum of naturally infected ruminants might provide insight on the mechanism of their infection in different hosts. In the present study, whole-cell protein extracts of B. abortus and B. melitensis were separated using SDS-PAGE and western blotting was performed using field sera from cows, buffaloes, sheep and goats. Protein bands that matched with western blot signals were excised, digested with trypsin and subjected to protein identification using MALDI-TOF MS. Identified proteins included heat shock proteins, enzymes, binding proteins and hypothetical proteins. Antibodies against the same set of antigen were found for all species investigated, except for superoxide dismutase of B. melitensis for which antibodies were demonstrated only in sheep serum. Brucellae appear to express these proteins mainly for their survival in the host system during infection.
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PMID:Proteomics-based identification of immunodominant proteins of Brucellae using sera from infected hosts points towards enhanced pathogen survival during the infection. 2544 24