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)

Ia antigens from the I-A8 and I-Ck subregions of the B10.HTT (H-2t3) strain of mice were isolated by indirect immunoprecipitation of arginine-labeled, nonionic detergent-solubilized materials. After biochemical purification the electrophoretically homogeneous 28,000 dalton glycoprotein beta chains from the Ia precipitates were digested with trypsin and the resultant radiolabeled tryptic peptides were compared by analytical ion exchange chromatography. These comparisons reveal that the beta chains of Ia antigens from the A (I-A8) and C (I-Ck) subregions of B10.HTT share only two out of 12 to 14 of their arginine tryptic peptides. Thus these noncross-reactive Ia antigens are structurally quite diverse, and would possess sufficient structural variability to account for their lack of antigenic cross-reactivity.
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PMID:Structural studies of the protein portion of the H-2-linked Ia glycoprotein antigens of the mouse: tryptic peptide comparison of products from the I-A and I-C subregions of B10-HTT. 7 48

The ascites form of a chemically induced guinea pig hepatoma, line-10, was resistant to killing in vitro by xenogeneic antibody and guinea pig complement. Pretreatment of line-10 cells with certain proteolytic enzymes rendered tham susceptible to the killing action of antibody and guinea pig complement. The effects of enzyme pretreatment were dependent on enzyme concentration, temperature, and could be blocked by addition of competitive or non-competitive inhibitors. The effect of the enzyme treatment could reversed by incubating the treated cells at 37 degrees C (but not at 0 degrees C), in the absence of the enzyme. Effective enzymes included ficin, bromelain, pronase, elastase, papain, trypsin, collagenase, lipases type I and type VI, and the neuraminidase preparation isolated from Clostridium perfringens. The activity of the lipase preparations and the neuraminidase preparation isolated from Clostridium perfringens appeared to be caused by proteolytic enzyme contamination. Enzyme preparations that proved ineffecitve in rendering the line-10 cells sensitive to killing by antibody and guinea pig complement included DNase, RNase, beta-glucuronidase type 6A or type B10, hyaluronidase type V or type VI, and pectinesterase.
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PMID:Lysis of tumor cells by antibody and complement. VI. Enhanced killing of enzyme-pretreated tumor cells. 17 70

Since peptide mapping with proteolytic enzymes such as trypsin and Staphylococcus aureus V8 protease is a powerful tool for the characterization of proteins, investigators should be cognizant of possible artifacts due to the technique itself. This article describes the identification of minor peaks found in the maps of recombinant human relaxin and insulin-like growth factor I as transpeptidation products. Both proteins have some homology to insulin with relaxin being composed of two chains designated A and B, while insulin-like growth factor I is composed of a single polypeptide chain. Digestion of relaxin with trypsin at pH 7.2 yields two peptides, T2,3(A10-18) and T7(B10-13), linked together by a disulfide bond. An unexpected component at a 10% level was identified to be the T2-T7 peptide pair where T3(ArgA18) has formed a peptide bond with the amino-terminal LeuB10 of the T7 peptide. It was also observed that the digestion of insulin-like growth factor I with V8 protease normally yields two peptides V4(13-20) and V9(59-70) linked by a disulfide bridge. A minor peak at a 1 to 2% level was identified to be a single polypeptide resulting from the formation of a peptide bond between the amino-terminal Met59 of V9 and the carboxyl-terminal Asp20 of V4, with the disulfide bond intact. These transpeptidation products were isolated by reversed-phase HPLC and identified using amino-terminal sequence and mass spectrometric analyses.
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PMID:Transpeptidation during the analytical proteolysis of proteins. 188 34

Terminal deoxynucleotidyl transferase (terminal transferase) was specifically modified in the DNA binding site by a photoactive DNA substrate (hetero-40-mer duplex containing eight 5-azido-dUMP residues at one 3' end). Under optimal photolabeling conditions, 27-40% of the DNA was covalently cross-linked to terminal transferase. The specificity of the DNA and protein interaction was demonstrated by protection of photolabeling at the DNA binding domain with natural DNA substrates. In order to recover high yields of modified peptides from limited amounts of starting material, protein modified with 32P-labeled photoactive DNA and digested with trypsin was extracted 4 times with phenol followed by gel filtration chromatography. All peptides not cross-linked to DNA were extracted into the phenol phase while the photolyzed DNA and the covalently cross-linked peptides remained in the aqueous phase. The 32P-containing peptide-DNA fraction was subjected to amino acid sequence analysis. Two sequences, Asp221-Lys231 (peptide B8) and Cys234-Lys249 (peptide B10), present in similar yield, were identified. Structure predictions placed the two peptides in an alpha-helical array of 39 A which would accommodate a DNA helix span of 11 nucleotides. These peptides share sequence similarity with a region in DNA polymerase beta that has been implicated in the binding of DNA template.
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PMID:Interactions of photoactive DNAs with terminal deoxynucleotidyl transferase: identification of peptides in the DNA binding domain. 200 41

The phenomenon of natural (innate) resistance is exemplified by the solid resistance of mice to infection with the rat-specific Trypanosoma lewisi. We provide more information about the mechanism of resistance in this model system. Resistance was not diminished in aged mice or reduced by ionizing radiation or splenectomy. There was no difference in resistance of C5-deficient mice (B10.D2/oSn and AKR) compared with their normocomplementemic counterparts (B10.D2/nSn and C57BL/6). Treatment of mice with cobra venom factor resulted in greatly prolonged survival of T. lewisi in mice. Combined treatment of mice with cobra venom factor and silica dust resulted in not only prolonged survival but also considerable intravascular growth of the parasite and resultant death of the mice. T. lewisi cells from irradiated donor rats, or after surface coat removal with trypsin, were eliminated by inoculated mice more efficiently than were parasites acquired from normal rats. Incubation of trypanosomes obtained from irradiated rats in normal rat serum restored their resistance to rapid elimination. From the results of these studies and other recent investigations, we have concluded that murine resistance to T. lewisi involves activation and binding of C3b by uncoated trypanosomes and concomitant participation of radiation-resistant, silica dust-sensitive effector cells (probably macrophages and neutrophils), and rat plasma proteins, integrated into the trypanosome surface coat, stabilize the coat, make it less susceptible to removal when the trypanosome is present in the mouse bloodstream, and thus delay exposure of underlying molecules (receptors?) that activate murine C3.
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PMID:Murine natural resistance to Trypanosoma lewisi involves complement component C3 and radiation-resistant, silica dust-sensitive effector cells. 298 Nov 95

The ferredoxin (Fd) molecule is a small non-mammalian immunogenic protein containing 55 amino acid residues with only two major antigenic determinants located with the NH2-terminal heptapeptide and the COOH-terminal pentapeptide. Selective enzyme cleavages of Fd with either trypsin or carboxypeptidase A result in the inactivation of the antigenic determinants by the removal of a tripeptide at the NH2-terminal and two amino acid residues at the COOH-terminal, effectively leaving 52 and 53 amino acid fragments respectively, each containing a single antigenic determinant. Fd digested with both enzymes yielded a 50 amino acid peptide with both determinants inactivated. Purity of these digests was assessed using monoclonal antibodies in standard and antigen-blocking ELISAs. The doubly digested peptide had virtually no reactivity with anti-Fd sera, reconfirming that the central cysteine-rich region is serologically silent. It was found that the sum of the reactivities of the N- and C-determinant-bearing peptides as equal to that of the native Fd and that the ratio of the reactivities could be used to assess determinant selectivity in the response to Fd in congenic recombinant strains of mice. This method was used in mapping the determinant selectivity in the antibody response to the MHC of mice to the left of the I-B subregion. Use of the B10.HTT strain indicated that separate genes mapping to the same subregion code for the magnitude of the antibody response and the determinant selectivity of the response.
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PMID:The use of unideterminant fragments of ferredoxin in the genetic mapping of determinant specificity of the immune response. 618 Mar 12

Monoclonal antibody 384.5 specifically inhibited cytolysis of P-815 target cells by cloned L3 cytotoxic T lymphocyte (CTL) effector cells. The lytic activity of other cloned CTL that have other distinct specificities was not affected. Antibody 384.5 did not inhibit the cytolytic activity of bulk populations of C57BL/6 mixed lymphocyte culture (MLC) cells. Concanavalin A-facilitated cytolysis by T cell clone L3 but not T cell clone B18 was inhibited by antibody 384.5, whereas phytohemagglutinin-facilitated cytolysis by L3 cells was not strongly inhibited. Antibody 384.5 binds specifically to L3 cells but not to several other T lymphocytes clones, or to a detectable portion of populations of primary MLC cells, normal spleen, thymus, lymph node, or bone marrow cells. In contrast, C57BL/6 anti-B10.A(5R) secondary MLC cells (genetically enriched for reactivity against the H-2Dd region gene products) contained a small population which reacted with the antibody 384.5. The determinant detected by antibody 384.5 was susceptible to trypsin treatment, and was reexpressed after overnight incubation. These results suggest that the monoclonal antibody 384.5 detects an endogenously synthesized clone-specific determinant associated with the cytolytic activity of the L3 CTL clone. These properties make antibody 384.5 an attractive candidate for an antibody that reacts with the antigen-recognition site of a cytolytic T cell antigen receptor.
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PMID:A clone-specific monoclonal antibody that inhibits cytolysis of a cytolytic T cell clone. 618 81

Culture supernatant fluids from spleen cells from C57BL/10 or BALB/c mice neonatally treated with semiallogeneic (B 10.D2 x B10)F1 cells to induce haplotype-specific suppressor T cells and restimulated with macrophages syngeneic at I-A with the allogeneic haplotype encountered as neonates contain a soluble factor capable of suppressing primary in vitro antibody responses of normal syngeneic spleen cells in a non-antigen-specific manner. This haplotype-specific suppressor factor, TsF-H, has also been recovered in culture fluids of a T cell hybridoma produced by fusion of the AKR thymoma BW5147 and the haplotype-specific suppressor T cells. TsF-H is inactivated by low pH (3.5) trypsin, for 30 min at 50 degrees C, and has a molecular weight in the range of 45,000 to 68,000. Studies with specific immunoabsorbents demonstrate the presence of determinants encoded by the I-A subregion of the haplotype of the T cell producing TsF-H but not I-J subregion or immunoglobulin constant-region determinants on the TsF-H. Suppression is restricted to primary in vitro antibody responses, and not secondary antibody, mixed lymphocyte, or cytotoxic lymphocyte responses by spleen cells syngeneic at the I-A subregion of H-2 with the T cell producing the factor. The properties and activities of TsF-H and the haplotype-specific suppressor T cell are compared and contrasted with antigen-specific and genetically restricted suppressor T cells and their factors.
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PMID:Haplotype-specific suppression of antibody responses in vitro. II. Suppressor factor produced by T cells and T cell hybridomas from mice treated as neonates with semiallogeneic spleen cells. 645 57

Bf protein was directly precipitated from a mixture of EDTA-plasma from 13 different, inbred strains and rabbit IgG anti-mouse Bf, and was isolated by SDS-PAGE. The gel pieces containing Bf protein were digested by trypsin after labeling with 125I-Na, and then peptides of Bf protein with each mouse strain were compared by two-dimensional peptide mapping. The results for the peptide patterns with the standard B10 congenic strains (all of which Bf phenotypes had been already designated as Bf.1 because of the identical isoelectric point values) revealed two distinct peptide patterns. The peptide pattern of Bf protein appeared to be identical in each of the inbred strains, but only one of the 36 spots in the fingerprint observed either with B10 or B10.BR (designated tentatively as Bf.1 (b.k.) ) was not detected in that from B10.D2 and B10.S (designated tentatively as Bf.1 (d.s.) ). The results of peptide mapping with intra-H-2 recombinant inbred strains show that this structural variant was mapped to the S region, which is direct evidence that allotypes of murine Bf are encoded by a structural gene within the MHC.
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PMID:Allotypes of murine factor B controlled by a locus within the S region of the H-2 complex. 656 32

The gene encoding catalase-peroxidase was cloned from chromosomal DNA of Rhodobacter capsulatus B10. The nucleotide sequence of a 3.7-kb SacI-HindIII fragment, containing the catalase-peroxidase gene (cpeA) and its flanking regions were determined. A 1728-bp open reading frame, coding for 576 amino acid residues (molecular mass 61516 Da) of the enzyme, was observed. A Shine-Dalgarno sequence was found 5 bp upstream from the translational start site. The deduced amino acid sequence coincides with that of the amino terminus and of four peptides derived from trypsin digestion of the purified catalase-peroxidase of R. capsulatus B10. The amino acid sequence of R. capsulatus catalase-peroxidase shows interesting similarities to the amino acid sequences of the hydroperoxidases of Escherichia coli (42.7%) and Salmonella typhimurium (39.9%), the peroxidase of Bacillus stearothermophilus (32.1%) and the catalase-peroxidase of Mycobacterium intracellulare (42.2%). As shown by a cpeA::lacZ fusion in trans in R. capsulatus, the expression of the catalase-peroxidase gene is regulated by oxygen. The promoter of the cpeA gene was localized within 320 bp upstream of the ATG start codon.
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PMID:Molecular cloning, sequence analysis and expression of the gene for catalase-peroxidase (cpeA) from the photosynthetic bacterium Rhodobacter capsulatus B10. 850 96


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