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 affinity to the matrix protein, one of the major outer membrane proteins of Escherichia coli, for the peptidoglycan was examined of extracting the cell envelope complex at 55 degrees C and 2% sodium dodecyl sulfate containing different amounts of NaCl. It was found that the matrix protein was extracted from the peptidoglycan of a mutant strain (lpo) that lacks another major membrane protein, the lipoprotein, at a lower NaCl concentration than was the matrix protein of the wild-type cell (lpo+). When the envelope fraction of the wild-type strain was treated with trypsin, which is known to cleave the bound-form lipoprotein from the peptidoglycan, the affinity of the matrix protein for the peptidoglycan decreased to the same level as that of the affinity of the matrix protein for the peptidoglycan of the mutant strain. It was further shown that the free-form lipoprotein was also retained in the matrix protein-peptidoglycan complex, although the extent of retention of the free form of the lipoprotein was less than that of the matrix protein. These results indicate that both the free and the bound forms of the lipoprotein are closely associated with the matrix protein and that the bound form of the lipoprotein plays and important role in the association between the matrix protein and the peptidoglycan.
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PMID:Interaction between two major outer membrane proteins of Escherichia coli: the matrix protein and the lipoprotein. 33 85

After polyadenylation in vitro of the influenza virus RNA segment which contains the coding information for the matrix protein, a cDNA copy can be made using the primer p(dT)8-dA and reverse transcriptase. The sequence of 166 nucleotides of the cDNA was determined by a modification [Brownlee, G. G. & Cartwright, E. M. (1977) J. Mol. Biol, 114, 93--117] of the plus/minus method [Sanger, F. & Coulson, A. R. (1975) J. Mol. Biol. 94, 441--481] and adaptation of the "dideoxy" method [Sanger, F., Nicklen, S. & Coulson, A. R. (1977) Proc. Natl. Acad. Sci. U.S.A. 74, 5463--5467] for sequencing DNA. The cDNA sequences is of the same sense as the mRNA for matrix protein and contains a potential initiating codon, d(ATG), at position 26--28. When matrix protein purified from virus particles was digested with chymotrypsin or trypsin and the amino acid compositions of separated peptides determined, one peptide containing nine amino acids found which had a composition corresponding to that predicted by the cDNA sequence following the first methionine codon, confirming that protein synthesis initiates at this position. The compositions of four other peptides matches those predicted from the nucleotide sequence. There is no processing of the N terminus of the protein before incorporation into the virus particle except for removal of the N-terminal methionine and addition of a "blocking" group on the resulting N-terminal serine residue.
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PMID:Nucleotide sequence coding for the N-terminal region of the matrix protein influenza virus. 57 97

We have identified a unique mesangial matrix protein of the human glomerulus by using a monoclonal antibody, 1G10, generated against culture human glomerular cells. By immunofluorescence, the antigen recognized by 1G10 (1G10 antigen) is present in mesangium and smooth muscle tissue and cannot be detected in any other tissue examined. Immunoelectron microscopy of glomeruli indicated that 1G10 antigen is present exclusively in the mesangial matrix at the endothelial-mesangial interface. The 1G10 antigen is also expressed by cultured mesangial cells, but not by cultured glomerular epithelial cells, umbilical endothelial cells or fibroblasts. 1G10 did not react with the mesangial matrix proteins [fibronectin (FN), laminin (LAM), collagen types I, III, IV, V, and VI (Col I, III, IV, V, VI), heparin sulfate proteoglycan (HSPG), or thrombospondin (TS)] present under normal and diseased states or smooth muscle antigens (myosin, actin), but did react with a 4 M urea extract of renal cortex and a 0.3% deoxycholate extract of isolated glomeruli. Two dimensional immunoblot analysis using the urea extract demonstrated the binding of 1G10 to an approximately 200 KDa polypeptide with pI 6.0. On one dimensional immunoblot this band did not show cross react with polyclonal antisera to FN, LAM, Col IV, V, VI, HSPG or TS. This mesangial matrix component is trypsin and periodate sensitive, suggesting that it has the character of glycoprotein. In renal biopsy specimens from patients with mesangial proliferative glomerulonephritis (GN) and membranoproliferative GN, the expression of the 1G10 antigen increased along with mesangial hypercellularity or increased accumulation of mesangial matrix, but decreased in completely sclerosed glomeruli. No significant changes in 1G10 antigen expression was observed in membranous GN or minimal change nephrosis compared to normal glomeruli. This study suggests that the 1G10 antigen may not only be a useful marker for the clinical assessment of GN, but may also serve as a potential tool for the study of the pathogenesis of glomerular diseases characterized by cellular proliferation and mesangial matrix expansion.
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PMID:A monoclonal antibody (1G10) recognizes a novel human mesangial antigen. 140 47

Extracellular storage of thyroglobulin (TG) is an important prerequisite for maintaining constant levels of thyroid hormones in vertebrates. Storage of large amounts is made possible by compactation of TG in the follicle lumen with concentrations of at least 100-400 mg/ml. We recently observed that the luminal content from bovine thyroids can be isolated in an intact state and be separated from soluble TG. For this purpose, bovine thyroid tissue was homogenized and subjected to various steps of purification. This procedure resulted in a pellet of single globules measuring 20-120 microns in diameter. Scanning electron microscopy revealed a unique cobblestone-like surface pattern of isolated globules, showing in detail the impressions of the apical plasma membranes of thyrocytes which had formerly surrounded the luminal content before tissue homogenization. Isolated thyroid globules were rapidly digested by trypsin but extremely resistant to various protein solubilization procedures. Homogenization of isolated globules resulted in the release of approximately 3% of total protein, showing that only a minor proportion of TG was loosely incorporated in thyroid globules whereas approximately 22% appeared to be interconnected with the globule matrix by disulfide bridges. Analysis by SDS-gel electrophoresis and immunoblotting confirmed that the protein released by this procedure consisted of TG. The vast majority (approximately 75%) of the globule matrix protein was found to be covalently cross-linked by non-disulfide bonds. TG in isolated globules was highly iodinated (approximately 55 iodine atoms per 12-S TG subunit) suggesting that the covalent nondisulfide cross-linking occurs in part during the iodination of TG and that this process involves the formation of intermolecular dityrosine bridges. Mechanisms must exist which solubilize or disperse the insoluble luminal content prior to endocytosis of TG.
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PMID:Isolation of insoluble secretory product from bovine thyroid: extracellular storage of thyroglobulin in covalently cross-linked form. 151 90

Revertants were isolated from the protease activation mutant of Sendai virus, F1-R, which causes a systemic infection in mice. The fusion (F) glycoprotein of F1-R is susceptible to activation cleavage by ubiquitous cellular proteases and is thus responsible for pantropism in mice (Tashiro et al., 1988. Virology 165, 577-583). The revertants regained several phenotypes of wild-type virus; they required exogenous trypsin for activation of the F protein in cell cultures and in nonpulmonary mouse tissues and they were exclusively pneumotropic in mice. On the other hand, phenotypes of F1-R that remained unchanged by the revertants were bipolar budding in polarized epithelial cells, enhanced electrophoretic migration of the matrix protein, and the lack of a glycosylation site in the F2 subunit of the F protein. Comparative RNA sequence analysis of the F gene of the revertants revealed that the reduced cleavability of the F protein of the revertants was the result of the predicted single amino acid reversion (Pro to Ser) at residue 115 adjacent to the cleavage site. Thus the sequence at the cleavage site of the revertants was Ser-Lys compared with Pro-Lys for F1-R and Ser-Arg for wild-type virus. The results indicate that enhanced cleavability of the glycoprotein, a feature often associated with multiple basic residues within the cleavage site of paramyxovirus F proteins and influenza virus hemagglutinins, can also be determined by a single basic amino acid following proline. Additionally, the revertants were less susceptible to the activator for wild-type virus present in mouse lungs and less pathogenic for this organ than wild-type virus. These results provide further evidence that proteolytic activation of the F protein by host proteases is the primary determinant for organ tropism and pathogenicity of Sendai virus in mice. One of the revertants was also temperature sensitive (ts); the ts lesion in the nucleoprotein gene was identical to that found in ts-f1, the ts host range mutant from which F1-R was derived.
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PMID:Pneumotropic revertants derived from a pantropic mutant, F1-R, of Sendai virus. 165 90

The surface of Aeromonas salmonicida is covered by a tetragonal paracrystalline array (A-layer) composed of a single protein (A-protein, Mr = 50,778). This array is a virulence factor. Cells containing A-layer and isolated A-layer sheets specifically bound laminin and fibronectin with high affinity. Binding by cells was inactivated by selective removal of A-layer at pH 2.2, and neither isogenic A-layer-deficient A. salmonicida mutants nor tetragonal paracrystalline array producing Aeromonas hydrophila and Aeromonas sobria strains bound either matrix protein. Laminin binding was by a single class of high affinity interactions (cell Kd = 1.52 nM), whereas fibronectin bound via two classes of interactions, one being similar to that of laminin (cell Class 2 interaction Kd = 6.6 nM). This interaction with both proteins was partly hydrophobic. The Class 1 fibronectin interaction was of lower affinity (cell Kd = 218 nM) and distinct. Purified A-protein inhibited binding of both matrix proteins to A-layer, and trypsin cleavage localized the matrix-protein binding region to the N-terminal major trypsin-resistant structural domain of A-protein. Monoclonal antibody inhibition studies showed that A-protein was folded such that Fabs of only one of two antibodies with epitopes mapping C-terminal to this trypsin-resistant peptide was capable of blocking binding.
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PMID:Binding of laminin and fibronectin by the trypsin-resistant major structural domain of the crystalline virulence surface array protein of Aeromonas salmonicida. 173 Jun 7

The major 64-kDa structural protein of human cytomegalovirus (pp64) was isolated from a guanidinium chloride extract of the virions and dense bodies of HCMV (Towne) by reverse-phase HPLC. Purified pp64 was reduced and alkylated followed by digestion with trypsin. The molecular mass of each of the tryptic peptides was determined by fast atom bombardment/mass spectrometry and compared with the predicted molecular mass of the fragments deduced from the corresponding DNA-derived peptide sequence of pp65 from HCMV (AD169). Microsequence analysis was employed to confirm selected peptides. Results of protein sequence analysis of pp64 from HCMV (Towne) are in complete agreement with the DNA-derived protein sequence of pp65 predicted for HCMV (AD169) with the following exceptions and modifications. The protein isolated from HCMV (Towne) was found to contain an Ala at position 448 instead of Ser448 reported for the protein from HCMV (AD169). We also identified Ser472 as a site of phosphorylation in pp64 from HCMV (Towne). Finally, on the basis of the sequence of HCMV (AD169) DNA fragment encoding the matrix protein and on S1 nuclease protection analysis, it has been predicted that one version of the matrix protein (possibly the lower matrix protein, Mr 65K) is encoded by an mRNA that is formed through splicing of a short intron. However, we have obtained peptides that contain sequences spanning through the splice-junction region, suggesting that in HCMV (Towne), the matrix protein is encoded by an unspliced message.
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PMID:Structural analysis of a 64-kDa major structural protein of human cytomegalovirus (Towne): identification of a phosphorylation site and comparison to pp65 of HCMV (AD169). 216 61

The Minnesota strain of turkey enteric coronavirus (TCV) was grown on a human rectal tumor (HRT-18) cell line in the presence of radiolabeled amino acids and glucosamine to analyse virion structural proteins. In addition to the 52,000 unglycosylated nucleocapsid protein, three major glycoprotein species were found to be associated with the viral envelope. A predominant glycosylated protein with a molecular weight of 22-24,000 represented the transmembrane matrix protein. Larger glycoproteins with apparent molecular weights of 180-200,000 (gp 200), 120-125,000 (gp 120) and 95-100,000 (gp 100) were associated to the characteristic large bulbous projections (peplomers) located at the surface of the virion. The gp 100 and gp 120 species apparently arose from a proteolytic cleavage of gp 200, as suggested by digestion studies with trypsin and chymotrypsin. An additional large glycoprotein with mol. wt. of 140,000 (gp 140), that behaved as a disulfide-linked dimer of a 66,000 molecule, was found to be associated to granular projections located near the base of the large peplomers. Digestion studies with trypsin, bromelain and pronase demonstrated that gp 140 was related to the hemagglutinating activity of the virus. An inner membranous sac or tongue-shaped structure could be visualized in the interior of the viral particles following treatment with pronase. In contrast, trypsin or chymotrypsin treatments resulted in evaginations ("budding") on the virus surface. Progeny viral particles produced in TCV-infected cell cultures in the presence of tunicamycin lacked both types of surface projections, as demonstrated by electron microscopy and electrophoresis. The matrix protein also appeared to be reduced to its unglycosylated form, concomitant with a considerable loss of its antigenicity. Thus, with respect to its morphological and biochemical characteristics, TCV resembles viruses belonging to the group of mammalian hemagglutinating coronaviruses, but differs in that both types of envelope glycoproteins are N-glycosylated as in case of the avian infectious bronchitis virus.
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PMID:Identification and location of the structural glycoproteins of a tissue culture-adapted turkey enteric coronavirus. 267 55

Recent evidence indicates that human alveolar macrophages can degrade purified elastin in vitro by a cell contact-dependent process involving acidic proteinases of the cysteine proteinase class. It is unclear to what extent these cells can degrade elastin within a natural extracellular matrix. To address this question, we cultured live human alveolar macrophages on elastin-rich, 3H-lysine-labeled, extracellular matrices deposited by rat smooth muscle cells in vitro. Under various culture conditions, we then measured release of total radioactivity from the matrices during co-culture with cells as well as net loss of desmosine/isodesmosine as a specific marker of elastin degradation. Live macrophages adhered to and progressively solubilized matrix protein at a slow rate (approximately 5 micrograms/10(6) cells/24 h) but the rate of solubilization increased more than 15-fold in the presence of plasminogen. The elastin component of the complicated matrix was not measurably degraded in the absence of plasminogen, but in medium containing plasminogen, 3.5 X 10(6) macrophages degraded 25 +/- 8 micrograms of elastin in 72 h. After pretreatment of matrices with trypsin to remove glycoprotein elements, live cells degraded 16 +/- 4 micrograms of elastin under plasminogen-free conditions. The addition of serum to the medium (1 to 5%) inhibited degradation of elastin within whole matrices (approximately 50% compared to serum-free medium containing plasminogen) but had no effect on degradation of elastin in trypsin-pretreated matrices. An active site inhibitor of cysteine proteinases, Z-phenylalanine-phenylalanine-diazomethylketone, blocked approximately 50% of the elastin degradation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Role of plasminogen activator in degradation of extracellular matrix protein by live human alveolar macrophages. 334 31

The human respiratory coronavirus OC43 was grown on a human rectal tumor cell line and was isotopically labeled with amino acids, glucosamine, and orthophosphate to analyze virion structural proteins. Four major protein species were resolved by electrophoresis and many of their properties were deduced from digestion studies using proteolytic enzymes. The four proteins are: A 190 kDa protein, the presumed peplomeric protein, that was glycosylated and proteolytically cleavable by trypsin into subunits of 110 and 90 kDa. The subunits each represent a different amino acid sequence on the basis of peptide mapping; a 130 kDa protein that was glycosylated and behaved as a disulfide-linked dimer of 65 kDa molecules. It is the apparent virion hemagglutinin on the basis of digestion studies with trypsin, bromelain and pronase; a 55 kDa nucleocapsid protein that was phosphorylated; a 26 kDa matrix protein that was glycosylated. The 190, 130, 55 and 26 kDa species can therefore be designated P, H, N and M, respectively. They exist in molar ratios of 4:1:33:33, and are calculated to be present at the rate of 88, 22, 726, and 726 molecules per virion, respectively.
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PMID:Structural proteins of human respiratory coronavirus OC43. 376 20


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