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)

An unusual glycoprotein variant (Pj) was found inherited through a caucasian family exhibiting atypical N and Nvg blood-group reactivities. Pj erythrocytes are blood-group-MS homozygous and have a normal sialic acid content. On sodium dodecyl sulphate/polyacrylamide-gel electrophoresis the variant contains a new component Pj of 24kDa apparent molecular mass in the monomeric state which is sharply stained by periodic acid/Schiff reagent. Both blood-group-MN (alpha) and -Ss (delta) glycoproteins were present. Homodimers (Pj2) as well as heterodimers with MN-glycoprotein (alpha Pj) and the Ss-glycoprotein (delta Pj) were also identified. The new sialoglycoprotein Pj is trypsin- and chymotrypsin-resistant in situ and carries N- and Nvg- but not M- and S-reactivities. The Pj component is labelled by lactoperoxidase-catalysed radioiodination. A 3H label is also easily introduced into the sialic acid or the galactose and galactosamine of the Pj glycoprotein. It is proposed that the Pj is a hybrid glycoprotein containing the N-terminal end of delta-glycoprotein and the C-terminal end of the alpha-glycoprotein. This proposal is supported by the finding that Pj carries a leucine residue at its N-terminus and is not immunoprecipitated by a monoclonal mouse antibody (R18) reacting specifically with the external domain of glycoprotein alpha. The red cells from the proposita Pj were found positive for a very low frequency MN antigen named Sta.
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PMID:Pj variant, a new hybrid MNSs glycoprotein of the human red-cell membrane. 705 58

To test whether urate crystal-membrane protein interactions mediate platelet stimulation, platelet membrane proteins were radiolabeled by lactoperoxidase, extracted with 1% Triton X-100, and incubated with urate crystals. The crystal-associated and supernate fractions were isolated and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and by 2-dimensional isoelectric focusing followed by SDS-PAGE. Four of the lactoperoxidase-radiolabeled polypeptides that associated with urate crystals had reduced molecular weights and pIs of Mr = 105,000, pI 4.9; Mr = 123,000, pI = 4.9; Mr = 123,000, pI = 5.3; and Mr = 132,000, pI = 4.8-6.3, respectively. These proteins were characterized with regard to their labeling intensities, apparent isoelectric points, apparent molecular weights (reduced and nonreduced), lectin-binding properties, carbohydrate- and protein-staining characteristic, and presence or absence in Glanzmann's thrombasthenia. They have been identified as derived from glycoproteins Ib, IIb, and III (Phillips-Agin nomenclature) and an unidentified membrane protein. To test whether removal of these proteins would result in a diminution of platelet response to urate, intact platelets were digested with chymotrypsin, resulting in cleavage of more than 80% of these proteins and a 5-fold reduction in secretory responsiveness to urate crystals. Response to a second platelet stimulus, collagen, was unaffected, indicating an intact secretory mechanism. In addition, when platelets were preincubated with F(ab')2 fragments of an antibody directed against these proteins, platelet secretory response to urate was inhibited by 50%, whereas the responses to collagen and thrombin were unaffected. Thus, membrane proteins appear to mediate platelet stimulation by urate crystals.
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PMID:The role of cell surface proteins in platelet stimulation by monosodium urate crystals. 708 98

The primary structure and surface exposure of the major outer membrane protein (MOMP) isolated from 14C intrinsically or 125I extrinsically radiolabeled Chlamydia trachomatis serotypes D/UW-3, G/UW-57, H/UW-4, I/UW-12, and L2/434 and the Chlamydia psittaci meningopneumonitis strain were analyzed by two different peptide-mapping techniques. Radiolabeled proteins were digested with either Staphylococcus aureus V8 protease, the patterns of peptide fragments produced being displayed by sodium dodecyl sulfate gel electrophoresis, or alpha-chymotrypsin, the peptides being analyzed after separation by high-voltage electrophoresis and thin-layer chromatography. The comparative structural data obtained from these two different techniques were remarkably similar. From these data, the following points could be made. (i) MOMPs are structurally heterogeneous between members of chlamydial species; the C. psittaci MOMP was clearly distinct from each of the C. trachomatis MOMPs. (ii) Considerable structural homology occurs among MOMPs from different C. trachomatis serotypes; however, distinct differences in the primary structure of each C. trachomatis MOMP were evident. (iii) These observed differences were most obvious in peptide maps of MOMPs isolated from chlamydiae that had been surface labeled by lactoperoxidase-mediated radioiodination. The surface-exposed portions of the MOMPs from serotypes L2 and D were very similar. In contrast, those from serotypes G, H, and I were quite different. These structural data are in agreement with the serospecificities described for these proteins.
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PMID:Structural analysis of chlamydial major outer membrane proteins. 715 81

1. The possibility of stabilizing water-soluble enzymes against the inactivation action of organic solvents by means of surfactants has been studied. Several enzymes (alpha-chymotrypsin (EC 3.4.21.1), trypsin (EC 3.4.21.4), pyrophosphatase (EC 3.6.1.1), peroxidase (EC 1.11.1.7), lactate dehydrogenase (EC 1.1.1.27) and pyruvate kinase (EC 2.7.1.40)) were used to demonstrate that enzymes can be entrapped into reversed micelles formed by surfactants (Aerosol OT, cetyltrimethylammonium bromide, Brij 56) in an organic solvent (benzene, chloroform, octane, cyclohexane). The enzymes solubilized in this way retain their catalytic activity and substrate specificity. 2. A kinetic theory has been put forward that describes enzymatic reactions occurring in a micelle-solvent pseudobiphasic system. In terms of this theory, an explanation is given for the experimental dependence of the Michaelis-Menten equation parameters on the concentrations of the components of a medium (water, organic solvent, surfactant) and also on the combination of the signs of charges in the substrate molecule and on interphase (++, +-, --). 3. The results obtained by us may prove important for applications of enzymes in organic synthesis and for studying the state and role of water in the structure of biomembranes and active centres of enzymes.
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PMID:The principles of enzyme stabilization. VI. Catalysis by water-soluble enzymes entrapped into reversed micelles of surfactants in organic solvents. 721 47

Boar spermatozoa were radioactively labeled by either lactoperoxidase-catalysed iodination or galactose oxidase oxidation followed by reduction with tritiated sodium borohydride. Plasma membrane glycoproteins were solubilized with the non-ionic detergent Nonidet P40 and separated by affinity chromatography on concanavalin A-Sepharose. A major water-soluble concanavalin A receptor of molecular weight greater than 160 000 was isolated by gel filtration and ion-exchange chromatography. Its amino acid and carbohydrate composition were determined. This glycoprotein is susceptible to digestion by trypsin or chymotrypsin.
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PMID:The isolation and characterization of a concanavalin A receptor from boar spermatozoa surface. 723 91

Band 3, the anion channel protein of the human erythrocyte, is the major transmembrane glycoprotein of the erythrocyte membrane. The protein is distributed in a broad 88,000-98,000-dalton band on gel electrophoresis. Previous investigations have defined an NH2-terminal cytoplasmic domain and an adjacent membrane-spanning domain of the Band 3 molecule. The fragments containing these domains appear as discrete bands by sodium dodecyl sulfate polyacrylamide gel electrophoresis. A carboxyl-terminal fragment of the Band 3 molecule was generated by digestion with chymotrypsin at the external face of intact erythrocytes. This fragment appears as a broad band of Mr = 34,000-45,000. It has a site accessible to lactoperoxidase at the internal face of the membrane and must, therefore, span the membrane. Slices from different regions of the broad electrophoretic band of the carboxyl-terminal fragment of Band 3 all have identical peptide maps. The same is true of Band 3. Therefore, despite their heterogeneous appearance on gels, Band 3 and its proteolytic fragments are homogeneous polypeptides. This conclusion is supported by the finding of an unique NH2-terminal tetrapeptide sequence for one Band 3 fragment. The apparent heterogeneity of Band 3 and its carboxyl-terminal region may reflect variability of glycosylation or sodium dodecyl sulfate binding.
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PMID:The carboxyl-terminal domain of human erythrocyte band 3. Description, isolation, and location in the bilayer. 724 Feb 19

Turnip isoperoxidase TP 7 had its hemin group removed and was cleaved by trypsin. The digest was fractionated by gel filtration and high-voltage paper electrophoresis and yielded 24 peptides, which counted for all 296 amino acid residues of the enzyme. Sequence analyses on the tryptic peptides and, when necessary, on their thermolytic derivatives were carried out by manual Edman degradation followed by dansylation or by quantitative amino acid analysis of thiazolinones converted by HI. The four disulfide bridges and the only site of carbohydrate attachment of turnip peroxidase 7 are located. The present analysis of tryptic peptides has been complemented by cyanogen bromide fragments cleaved by chymotrypsin as described in the accompanying paper.
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PMID:Covalent structure of turnip peroxidase 7. Tryptic peptides. 740 63

Hydrophobic interactions are important in numerous biological processes; however, the nature and extent of hydrophobic interactions in nonaqueous enzymology remain poorly defined. We have estimated the free energies of enzyme--substrate hydrophobic interactions for a model reaction catalyzed by subtilisin BPN'(from Bacillus amyloliquefaciens) in various solvents. Transition state stabilization of subtilisin in water has contributions from both ground state destabilization of hydrophobic substrates and intrinsic enzyme--substrate hydrophobic interactions. Both contributions are evident even in hydrophobic organic solvents and can be modified by protein engineering of the enzyme's binding site, as well as by changing the hydrophobicity of the reaction medium. We have also developed a method to estimate the hydrophobicity of the enzymic transition state involving systematic variation of the substrate and solvent hydrophobicities. The observed binding pocket hydrophobicities were directly affected by replacing the Gly166 residue, located at the back of hydrophobic S1 binding pocket of subtilisin BPN', with more hydrophobic amino acids such as alanine and valine. Thus, the observed S1 binding pocket hydrophobicities of the wild-type, G166A, and G166V mutants were measured to be 1.2, 1.8, and 2.6 log P units, respectively. Our method of calculating effective binding pocket hydrophobicity was found to be applicable to other enzymes, including horseradish peroxidase and alpha-chymotrypsin. Measurements of the binding pocket hydrophobicities have significant implications toward tailoring enzyme function in aqueous as well as nonaqueous media.
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PMID:Probing enzymic transition state hydrophobicities. 754 73

Using the system of reversed micelles of Aerosol OT1 in octane as an instrument revealing the possibility of supramolecular structures formation, we have shown that the native alpha-chymotrypsin can form complexes with glycoproteins. Dimers of the native alpha-chymotrypsin with the artificially glycosylated one and with horseradish peroxidase (natural glycoprotein) were obtained. The position of the optimum on the dependence of the catalytic activity upon the hydration degree confirms the compact organization of the formed complexes. The ability of alpha-chymotrypsin to form such kind of complexes seems to play a key role in its absorption on glycocalix in vivo.
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PMID:Lectin-like center in the molecule of alpha-chymotrypsin: formation of complexes with peroxidase and artificially glycosylated alpha-chymotrypsin. 766 20

Eosinophils contain many cytotoxic mediators including eosinophil peroxidase (EPO) in their granules and these mediators are released by various pathophysiological stimuli, resulting in severe damage to various epithelia. However, little is known about the intracellular mechanism of the degranulation. Here we report that eosinophils isolated from patients with bronchial asthma who were not taking corticosteroid hormone had significant amidolytic activities on Suc-Ala-Ala-Pro-Phe-MCA, and also that the activity was completely inhibited by chymostatin (1 x 10(-4) M), eglin C (1 x 10(-4) M), and peptide boronic acid (1 x 10(-4) M), indicating that eosinophils contain a chymotrypsin-like serine protease in the fraction eluted in 50 mM potassium phosphate buffer, pH 8.0 containing 2 M NaCl. Among the various types of protease inhibitors examined, one of the chymotrypsin-type proteases chymostatin (1 x 10(-4) M), but none of the other types of proteases such as leupeptin and E-64, markedly inhibited the EPO release (c.a. 60%) from eosinophils stimulated by immunoglobulin-G (2.5 mg protein/ml beads) in the presence of rhIL-5 (10 ng/ml) or platelet-activating factor (1 x 10(-7) M), although it had no effect on the release by calcium ionophore A23187 (1 x 10(-7) M).
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PMID:[Inhibition of eosinophil peroxidase release by chymotrypsin type protease inhibitors from activated human eosinophils]. 825 Jul 22


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