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 purification and characterization of the streptolytic exo-enzyme from the Maxted-McCarty strain of Streptomyces albus is described. This enzyme was shown to be an endo-N-acetylmuramidase with a molecular weight of 10 to 12,000 and optimal activity at pH 8 and 45 degrees C. The enzyme is lytic for streptococci of various groups, Micrococcus lysodeikticus, Staphylococcus aureus, as well as Escherichia coli. It closely resembles the F1 endo-N-acetylmuramidase described by Ghuysen et al. (1966) except for small differences in the products of lysis of streptococcal cell walls and the resistance of Escherichia coli to lysis by the F1 enzyme. Lysates of group A and A variant streptococcal cell walls prepared with purified Streptomyces albus muramidase contained serologically active M protein and C carbohydrate-peptidoglycan complexes. The chemical and immunological characteristics of these enzymmatic products of streptococcal cell walls are reported and their utility as immunologic reagents is described.
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PMID:Purification and characterization of a Streptomyces albus endo-N-acetylmuramidase lytic for group A and other beta haemolytic streptococci. 24 Jan 2

Two different molecular forms of bacteriolytic endo-N-acetylmuramidase (EC 3.2.1.17) were found in the Acanthamoeba castellanii culture. The enzymes were separated by column chromatography on DEAE-Sephadex or by polyacrylamide-gel electrophoresis. In young cultures only one molecular form of the enzyme was selectively secreted by amoeba cells to the environment. The second, more basic enzyme protein was preferentially synthesized by aging Acanthamoeba castellanii cells, and was also liberated to the medium. In amoeba cells the bulk of forms A and B of endo-N-acetylmuramidase are associated with subcellular organelles--lysosomes.
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PMID:Two forms of bacteriolytic endo-N-acetylmuramidase in Acanthamoeba castellanii. 75

We previously reported that group B streptococci (GBS) possess a cell-associated activity that inactivates the chemotactic activity generated in zymosan-activated serum by cleaving a specific site within the carboxy termini of C5a and C5adesarg. This inactivates the major chemoattractants for neutrophils that are generated when serum complement is activated. We now report the isolation of the enzyme responsible for the proteolytic cleavage of C5a. Treatment of GBS with mutanolysin, an endo-N-acetyl muramidase, released activity from GBS which destroyed the functional activity of C5a. The soluble activity was purified to homogeneity by hydroxyapatite, ion-exchange and gel-filtration chromatography. Analysis by SDS-PAGE showed that the enzyme (GBS C5a-ase) has an Mr of approx. 120,000. The GBS C5a-ase appears to be a serine esterase on the basis of its sensitivity to di-isopropyl fluorophosphate. This enzyme is distinct from the C5a-cleaving enzyme produced by group A streptococci, since the two bacterial products migrate differently on SDS-PAGE, and lack antigenic cross reactivity. This enzyme may play a role in the pathogenesis of group B streptococcal disease through its ability to rapidly inactivate the potent neutrophil agonist, C5a, at sites of infection.
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PMID:Purification of the proteinase from group B streptococci that inactivates human C5a. 191 45

This review is devoted to the bacteriolytic enzymes produced by many actinomycetes, mainly by Streptomyces genus. The bacteriolytic enzymes hydrolyse the specific bonds in bacterial peptidoglycans and cause the solubilization of the cellular walls and the disintegration of the bacterial cells. Many of the enzymes are purified to the electrophoretic homogeneity. The actinomycetes form the endo-N-acetylmuramidases more often, then the endopeptidases follow according to the frequency of occurrence, while the amidases and endo-N-acetylglucosaminidases are met rather seldom among the streptomycete-producers. The known amidases and exo-enzymes which are also produced by some species of actinomycetes are not related to the lytic enzymes proper. Almost all known endopeptidases from streptomyces hydrolyse the bridge peptide bonds in which the carboxyl group of terminal D-alanyl of peptide chain is involved. The bacteriolytic spectra of the different muramidases differ from each other and essentially differ from the spectrum of the egg-white lysozyme. Some endomuramidases from streptomyces are able to hydrolyse streptococci and some other important from the practical point of view microorganisms resistant to the action of lysozyme.
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PMID:[Bacteriolytic enzymes produced by actinomycetes. I. The physicochemical properties of the enzymes and the spectrum of their lytic action]. 305 15

Two groups of mutants altered in lytic enzyme activities have been isolated from Bacillus licheniformis 6346 MH-1 by screening clones for halo production in agar plates containing cell wall conjugated with Procion brilliant red. In the first group which produced halos during colony formation, two were shown to contain three- and eightfold more muramyl-l-alanine amidase than the parent. These strains liberated amidase and intracellular alpha-glucosidase into the culture medium during exponential growth in liquid medium. Isolated walls had a normal qualitative composition and in autolysing liberated N-terminal amino acids and reducing groups. Wall preparations from the second group of mutants which did not produce halos lysed very poorly at pH 9.5, the optimal pH for amidase activity, and poorly at pH 5.5 even though they had similar endo-N-acetylglucosaminidase activities to the parent. Two of these strains that were also deficient in phosphoglucomutase had only 3 to 5% of the membrane-bound amidase activity compared with that in the parent. Cell walls of the phosphoglucomutase-deficient mutants treated with sodium dodecyl sulfate to inactivate endogenous lytic enzymes were dissolved at 10% of the rate of those from the parent by added amidase, but their sensitivities to lysozyme were similar. Those from one mutant had 10 to 20% of the amidase-binding capacity of parent walls, whereas its isolated mucopeptide was essentially inactive in this respect. The failure of these phosphoglucomutase-deficient mutants to autolyse is likely to be due to the combined effects of both low amidase activity and resistant walls. As a result, daughter cells are unable to separate and long chains are formed during exponential growth.
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PMID:Characterization of Bacillus licheniformis 6346 mutants which have altered lytic enzyme activities. 482 3

A lytic enzyme was isolated and purified from PL-1 phage-induced lysates of the host Lactobacillus casei ATCC 27092. The molecular weight of the enzyme was about 30000. Maximum activity on the lysis of the host cell walls occurred at pH 6.0-6.5 and at 45 degrees C. The enzyme activity was inhibited by heavy metal ions, SH- and serine-enzyme inhibitors and o-phenanthroline. The reducing end of the enzymic digest was muramic acid and the enzyme was considered to be an endo-N-acetylmuramidase. However, the enzyme differed from the other known N-acetylmuramidases including hen's egg-white lysozyme in several enzymic properties.
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PMID:An N-acetylmuramidase induced by PL-1 phage infection of Lactobacillus casei. 642 95

A strong lytic activity against Micrococcus luteus was demonstrated in abomasal secretions from calf, adult cattle, goat and sheep. This bacteriolytic activity was undetectable in other secretions. Bacteriolysis was caused by a glycosidase displaying endo-N-acetylmuramoylhydrolase specificity (EC 3.2.1.17) and was further characterized in the calf. This lysozyme also displayed significant chitinase activity. Immunofluorescence microscopy confirmed the secretion of lysozyme by abomasal gastric glands exclusively. Electrofocusing revealed multiple molecular forms, the predominant one (more than 80%) being characterized by Mr approx. 15,000, pH optimum 5.0, pl 7.5 and remarkable conformational stability. The lytic activity of lysozyme was ionic strength dependent and competitive inhibition was observed with both N-acetyl glucosamine and N-acetyl-muramic acid. Amino-acid analysis demonstrated common characteristics with known lysozymes, i.e. four disulphide bridges, two proline and N-terminal lysine. Structural homology between the three ruminant lysozymes was established by immunological cross-reactivity.
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PMID:Lysozyme, an abomasal enzyme in the ruminants. 667 86

A glycosidase displaying endo-N-acetylmuramoylhydrolase specificity (EC 3.2.1.17) was isolated from calf rennet. This lysozyme was also present in abomasal secretions from calf and adult cattle. Multiple molecular forms revealed by electrofocusing might be artefacts. The main enzyme form had Mr approx. 15 000, pH optimum 5.0, pI7.5, and a remarkable conformation stability. Competitive inhibition was observed with both N-acetylglucosamine and N-acetylmuramic acid, with apparent Ki values of 29 mM and 2.4 mM respectively. The isolated enzyme also displayed significant chitinase activity.
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PMID:Calf rennet lysozyme. 680 89

The study of the kinetic curves of the lysis of group A S. pyogenes cell-walls (cells), serovars 29 and 12 M, variants M+ and M-; with endo-N-acetyl-muramidase revealed that the kinetics of the lysis of virulent and avirulent strains was different: variant M- was lyzed faster than M+. This difference in the cell-wall lysis of both variants made it possible to use this method for the identification of M+ and M- states of the strains. 18 group A S. pyogenes cultures were studied. The cultures isolated from healthy and sick children in an organized group belonged to variants both M+ and M-. The pepsin fragments of M-proteins of group A S. pyogenes, type M 1, isolated in dynamics from a carrier and a patient, were studied. Their amino acid compositions were studied, and differences between them were established. The data thus obtained indicate that heterogeneity is characteristic of both the surface structure of streptococci and the individual components of their surface, in particular, M-protein.
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PMID:[The M-protein heterogeneity of Streptococcus pyogenes strains isolated from clinically healthy and ill children in an organized collective]. 765 28