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:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The properties of the functional groups in a protein can be used as built-in-probes of the structure of the protein. We have developed a general procedure whereby the ionization constant and chemical reactivity of solitary functional groups in proteins may be determined. The method may be applied to the side chain of histidine, tyrosine, lysine, and cysteine, as well as to the amino terminus of the protein. The method, which is an extension of the competitive labeling technique using [3H]- and [14C]1-fluoro-2,4-dinitrobenzene (N2ph-F) in a double-labeling procedure, is rapid and sensitive. Advantage is taken of the fact that after acid hydrolysis of a dinitrophenylated protein, a derivative is obtained which must be derived from a unique position in the protein. The method has been applied to the solitary histidine residue of lysozyme, alpha-lytic protease, and Streptomyces griseus (S.G.) trypsin, as well as to the amino terminus of the latter protein. The following parameters were obtained for reaction with N2ph-F at 20 degrees C in 0.1 N KCl: the histidine of hen egg-white lysozyme, pKa of 6.4 and second-order velocity constant of 0.188 M-1 min-1; the histidine of alpha-lytic protease, pKa of 6.5 and second-order velocity constant of 0.0235 M-1 min-1; the histidine of S.G. trypsin, pKa of 6.5 and second-order velocity constant of 0.0328 M-1 min-1; the valyl amino terminus of S.G. trypsin, pKa of 8.1 and second-order velocity constant of 0.403 M-1 min-1. In addition, the results obtained provide clues as to the microenvironments of these functional groups, and indicate that the proteins studied undergo pH-dependent conformational changes which affect the microenvironment, and hence the chemical reactivity of these groups.
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PMID:A competitive labeling method for the determination of the chemical properties of solitary functional groups in proteins. 0 42

Microorganisms capable of producing L-pyrrolidonecarboxylate peptidase [L-pyrrolidonyl peptidase, EC 3.4.11.8] were screened and a strain of Bacillus amyloliquefaciens was chosen as one of the most potent producers of the enzyme. The enzyme was purified from lysozyme-lysate of the bacterial cells by salting out with ammonium sulfate, adsorption on DEAE-cellulose, covalent chromatography on PCMB-Sepharose and by gel filtration on Sephadex G-150. By these procedures, the enzyme was purified about 800-fold with an activity recovery of 9%, and the preparation was electrophoretically homogenous. The enzyme was most active and stable at pH 7-8. The presence of 2-mercaptoethanol and EDTA was effective for stabilizing the enzyme. The molecular weight was estimated to be 72,000 by the gel filtration method and to be 24,000 by SDS-polyacrylamide gel electrophoresis, suggesting that the enzyme is a subunit oligomer, presumably trimer. The enzyme was inactivated by the addition of PCMB, sodium tetrathionate, Hg2+ and Cu2+, but the activity lost was restored by the addition of 2-mercaptoethanol and EDTA. The purified enzyme split amide and ester linkages in L-pyroglutamyl derivatives of L-alanine, beta-naphthylamine, alpha-naphthol, and 4-methylumbelliferone, but was completely inert towards various peptides and esters used as substrates for usual amino- and carboxy-peptidases, and for endopeptidases such as trypsin, subtilisin and alpha-chymotrypsin.
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PMID:Purification and characterization of L-pyrrolidonecarboxylate peptidase from Bacillus amyloiliquefaciens. 2 93

Mycobacterium ulcerans produces an exotoxin in culture which, when inoculated into guinea pig skin, causes inflammation, necrosis, edema, and other histopathological changes resembling those in infections of humans. The toxin was resistant to heat and to alkalies and was moderately acid labile. Toxic activity was destroyed by Pronase, phospholipase, lipase, amylase, and glucosidase but not by trypsin, collagenase, cellulase, lysozyme, hyaluronidase, or neuraminidase. Toxic activity was resistant to treatment with 2-mercaptoethanol, urea, guanidine hydrochloride, p-chloromercuribenzoate, ethylenediaminetetraacetate, and sodium deoxycholate but was destroyed by sodium m-periodate and sodium dodecyl sulfate. The toxin was precipitated by a wide range of ammonium sulfate concentrations. Extraction with chlorofrom-methanol or petroleum ether destroyed its activity. Isopycnic density gradient ultracentrifugation in KBr produced a high-density lipoprotein layer with a 24-fold increase in specific activity. The results indicate that this toxin is a high-molecular-weight phospholipoprotein-polysaccharide complex.
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PMID:Further characterization of Mycobacterium ulcerans toxin. 3 Jun 94

Treatment of cells grown to exponential phase with 4% sodium dodecyl sulfate for 3 h at 100 degrees C resulted in solubilization of all cellular components except for peptidoglycan. In most strains, cells cultured in liquid gonococcal broth at pH 7.2 yielded a peptidoglycan composed primarily of N-acetylmuramic acid N-acetylglucosamine, alanine, glutamic acid, and diaminopimelic acid in a molar ratio of 1:1:2:1:1. The peptidoglycan in these cells accounted for 1 to 2% (dry weight) of the cells. However, in cells cultured at pH 6.0, the dry weight of peptidoglycan increased to 4 to 13%. Preliminary investigations indicated that the apparent increase in weight is strain dependent and is due in part to associated protein(s). Neisseria gonorrhoeae strain CS7 had elevated amounts of protein associated with the peptidoglycan regardless of growth pH. The peptidoglycan-protein complex could not be dissociated by additional extraction with sodium dodecyl sulfate, 10 M LiCl2, or ethylenediaminetetraacetate or by 7.5% polyacrylamide gel electrophoresis. The complex could be degraded by lysozyme, trypsin, chymotrypsin, Pronase B, and Chalaropsis sp. muramidase.
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PMID:Cell envelope of Neisseria gonorrhoeae CS7: peptidoglycan protein complex. 3 3

The alterations of tryptophan fluorescence parametres with pH may be due to: 1) conformational changes; 2) changes in the ionic state of groups capable of quenching the tryptophan fluorescence. The applications of the model of discrete forms of tryptophan allow one to separate these mechanisms and estimate the middle points of conformational changes and pK's of quenching groups. For chymotrypsin (CT) and chymotrypsinogen (CTG) conformational changes were registrated with middle points: CT pH 4.1 and 8.8; CTG -- pH 3.2 and 9.8, and pK's of histidines: CT -- 5.4 and 6.6; CTG -- 5.6 and 7.0. For trypsin conformational changes were shown with middle points: pH 3.2; 5.8; 8.5 and for lysozyme -- pH 5.9.
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PMID:[pH-dependence of fluorescence parameters of chymotrypsin, chymotrypsinogen, trypsin and lysozyme]. 3 49

1. A glycol-chitin-splitting enzyme without lysozyme (muramidase) activity has been found in calf serum. The enzyme also degrades colloidal chitin and is thus a true chitinase, 1,4-beta-poly-N-acetylglucosaminidase, without exo-beta-N-acetylglucosaminidase effect. 2. The enzyme is purified 1000-fold by ion-exchange chromatography and gel filtration. Its optimal activity is between pH 1.5-2.0 with glycol chitin and between pH 3-6 in a rather broad optimum with colloidal chitin as substrate. The optimal stability of the enzyme is in the pH interval 3.0-6.5 when tested by incubation with glycol chitin at 50 degrees C for 60 min. The optimal temperature for the degradation of glycol chitin is 40 degrees C when assayed at pH 1.5 and 51 degrees C when assayed at pH 3.5. 3. The enzyme is activated by moderate heating at pH 6.5. The highest relative activity, 135% is reached after 45 min incubation at 30 degrees C, pH 5 or after 30 min at 40, pH 2.4. By incubation with small amounts of trypsin at pH 6.5 at 3m degrees C the enzyme was temporarily activated. 4. The isoelectric point, pH 5.3, and the molecular weight, 47,000 +/- 3,000 were determined by respectively isoelectric focusing and gel filtration. 5. The Michaelis-Menten constant, Km = 0.76 +/- 0.05 (S.E.) mg/ml, was measured with glycol chitin as substrate.
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PMID:Bovine serum chitinase. 4 11

Three immunologically distinct types of polysaccharides have been isolated by diethylaminoethyl (DEAE) chromatography from the lipopolysaccharide extracts of group B Neisseria meningitidis. All types contain a set of common determinants, as well as distinct ones; all of these determinants are detectable by either immunodiffusion or enzyme-linked immunosorbent assay (ELISA). The polysaccharides elute from a Sepharose 4B column in the range of 2-3 x 10(5) daltons and have isoelectric points from 4.2 to 4.3. Their antigenicity is destroyed by oxidation but is unaffected by neuraminidase, lysozyme, or trypsin. One type of polysaccharide cross-reacts with the Gc2 polysaccharide of Neisseria gonorrhoeae in immunodiffusion systems. Chemical analysis indicates that these polysaccharides contain hexoses, hexosamines, 2-keto-3-deoxyoctonate, ethanolamine, and heptose; analysis of amino acids indicates protein contents of less than 0.05%. In contrast to the lipopolysaccharide from which they are derived, these polysaccharides contain no lipid A and less than 0.5% fatty acids. All three types are precipitated by wheat germ agglutinin but not by concanavalin A or fucose-binding protein. Specific inhibition of this precipitation can be achieved with N-acetyl glucosamine. These antigens may be the bases of a lipopolysaccharide-derived typing system for group B N. meningitidis.
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PMID:Lipopolysaccharide-derived serotype polysaccharides from Neisseria meningitidis group B. 8 91

Leukocyte extracts, trypsin, and lysozyme are all capable of releasing the bulk of the LPS from S. typhi, S. typhimurium, and E. coli. Bacteria which have been killed by heat, ultraviolet irradiation, or by a variety of metabolic inhibitors and antibiotics which affect protein, DNA, RNA, and cell wall synthesis no longer yield soluble LPS following treatment with the releasing agents. On the other hand, bacteria which are resistant to certain of the antibiotics yield nearly the full amount of soluble LPS following treatment, suggesting that certain heatlabile endogenous metabolic pathways collaborate with the releasing agents in the release of LPS from the bacteria. It is suggested that some of the beneficial effects of antibiotics on infections with gram-negative bacteria may be the prevention of massive release of endotoxin by leukocyte enzymes in inflammatory sites.
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PMID:Effect of leukocyte hydrolases on bacteria. XV. Inhibition by antibiotics, metabolic inhibitors, and ultraviolet irradiation of the release by leukocyte extracts, trypsin, and lysozyme of lipopolysaccharide from gram-negative bacteria. 9 59

1. An activator catalysing specifically conversion of latent forms of human leucocyte collagenase and gelatin-specific protease into the active forms, has been isolated from rheumatoid synovial fluid and purified 55-fold with a yield of 16%. 2. Molecular weight of the activator is about 35 000. 3. The activator is thermolabile, and is irreversibly inactivated at pH below 5.5 or in the presence of low concentrations of trypsin or papain; it is resistant to the action of lysozyme, hyaluronidase, diisopropylfluorophosphate, soybean trypsin inhibitor, p-chloromercuribenzoate, iodoacetamide and dithiothreitol. 4. The activator did not show any activity towards collagen, gelatin, casein, haemoglobin, histones, elastin or p-phenylazobenzyloxycarbonyl-peptide.
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PMID:Isolation, purification and properties of a factor from rheumatoid synovial fluid activating the latent forms of collagenolytic enzymes. 17 Jul 64

We have studied cells dispersed with proteolytic enzymes from rheumatoid arthritic synovectomy specimens to determine the cell type(s) responsible for joint destruction. Initially 10-50% of these cells adhered to culture dishes within 24 hr and were of two main types: small, round cells and larger, stellate cells. During 1-4 days of culture, 5-25% had Fc receptors and 25-50% showed brisk phagocytosis. Daily producition, per 10(6) cells of collagenase (EC 3.4.24.3) (after trypsin pretreatment) was up to 70 mug of collagen fibrils lysed per min at 37 degrees (70 units), of prostaglandin (PGE2), up to about 1200 ng, and of lysozyme, up to about 100 mug. Under identical conditions of assay, fibroblasts grown from explants of synovium produced no detectable collagenase or lysozyme, and PGE2 was only 2-4 ng. With the dispersed cell preparations, macrophage markers (Fc receptors and lysozyme) were undetectable after 4 days and PGE2 decreased rapidly after about 7 more days. However, collagenase production continued for 3-25 weeks, and in some cultures, after cell passage. At these later stages, large, slow-growing stellate cells were predominant and could phagocytose carbon particles if incubated for greater than 6-8 hr. Indomethacin (14 muM) inhibited PGE2 but stimulated collagenase production whereas dexamethasone (10 nM) inhibited both. Production of PGE2 and collagenase in large amounts in vitro by these cells suggests that they may be involved in joint destruction in vivo. The precise origin of these synovial cells and the mechanisms responsible for the sustained production of collagenase at a high rate remain unidentified.
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PMID:Production of collagenase and prostaglandins by isolated adherent rheumatoid synovial cells. 17 63


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