Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.4 (deaminase)
 5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peptidoglycan monomer, GlcNAc-beta-(1----4)-MurNAc-L-Ala-D-iGln[ (L)-meso-A2pm-(D)-amide-(L)-D-Ala-D-Ala] (PGM), from Brevibacterium divaricatum is composed of the disaccharide pentapeptide containing muramic acid with a reducing end (ca. 90-95%) and of the anhydromuramyl analogue (anhydromuranyl-PGM; ca. 5-10%), according to analysis by high-performance liquid chromatography (HPLC) and fast atom bombardment mass spectrometry (FAB-MS). The two peptidoglycan analogues cannot be separated by simple physico-chemical procedures. The enzyme N-acetylmuramyl-L-alanine amidase (mucopeptide amidohydrolase, E.C. 3.5.1.28) cleaves the bond between N-acetylmuramic acid and L-alanine in the PGM molecule. It is shown that anhydromuramyl-PGM is also a substrate for the amidase. In a preparation containing both analogues, the amidase hydrolyses preferentially PGM rather than anhydromuramyl-PGM. The experimental conditions for treatment with the amidase were adjusted with respect to time and enzyme concentration to allow hydrolysis to proceed for several hours. The course of hydrolysis was followed by analysis of the unhydrolyzed substrate by HPLC, and FAB-MS at predetermined time intervals; after 6 h, the amount of anhydromuramyl-PGM in the unhydrolyzed substrate increased to 25% as compared to the starting material containing only 6%. Such a mixture was suitable for separation of components by preparative thin-layer chromatography and for isolation of completely purified PGM and the corresponding anhydromuramyl analogue containing an intramolecular 1,6-anhydromuramyl end. The separated purified compounds were characterized by HPLC and their structure confirmed by FAB-MS-MS.
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PMID:Comparative susceptibility of a peptidoglycan monomer from Brevibacterium divaricatum and its anhydromuramyl analogue to hydrolysis with N-acetylmuramyl-L-alanine amidase. Isolation and characterization of anhydromuramyl-peptidoglycan monomer. 290 Feb 48

Autolysin-defective pneumococci continue to synthesize both peptidoglycan and teichoic acid polymers (Fischer and Tomasz, J. Bacteriol. 157:507-513, 1984). Most of these peptidoglycan polymers are released into the surrounding medium, and a smaller portion becomes attached to the preexisting cell wall. We report here studies on the degree of cross-linking, teichoic acid substitution, and chemical composition of these peptidoglycan polymers and compare them with normal cell walls. peptidoglycan chains released from the penicillin-treated pneumococci contained no attached teichoic acids. The released peptidoglycan was hydrolyzed by M1 muramidase; over 90% of this material adsorbed to vancomycin-Sepharose and behaved like disaccharide-peptide monomers during chromatography, indicating that the released peptidoglycan contained un-cross-linked stem peptides, most of which carried the carboxy-terminal D-alanyl-D-alanine. The N-terminal residue of the released peptidoglycan was alanine, with only a minor contribution from lysine. In addition to the usual stem peptide components of pneumococcal cell walls (alanine, lysine, and glutamic acid), chemical analysis revealed the presence of significant amounts of serine, aspartate, and glycine and a high amount of alanine and glutamate as well. We suggest that these latter amino acids and the excess alanine and glutamate are present as interpeptide bridges. Heterogeneity of these was suggested by the observation that digestion of the released peptidoglycan with the pneumococcal murein hydrolase (amidase) produced peptides that were resolved by ion-exchange chromatography into two distinct peaks; the more highly mobile of these was enriched with glycine and aspartate. The peptidoglycan chains that became attached to the preexisting cell wall in the presence of penicillin contained fewer peptide cross-links and proportionally fewer attached teichoic acids than did their normal counterparts. The normal cell wall was heavily cross-linked, and the cross-linked peptides were distributed equally between the teichoic acid-linked and teichoic acid-free fragments.
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PMID:Peptidoglycan cross-linking and teichoic acid attachment in Streptococcus pneumoniae. 400 47

Peptidoglycan monomer (GlcNAc-MurNAc-L-Ala-D-isoglutamine-meso-diaminopimelic acid-D-Ala-D-Ala), labeled with 14C both in the disaccharide and pentapeptide portions, was incubated with slices of mouse liver, kidney or spleen as well as with mouse and human blood, blood cells plasma and serum. Peptidoglycan monomer was isolated unchanged after incubations with mouse organs and blood cells. However, upon incubation with mouse or human blood, 10-50% of the peptidoglycan monomer underwent hydrolysis to the corresponding disaccharide and pentapeptide. After incubations with plasma and serum more than 90% of the [14C]peptidoglycan monomer was metabolized: about 50% of the administered radioactive dose was recovered in the disaccharide unit and about 35% in the pentapeptide part. These results suggest that in blood, plasma and serum of mouse and man, an N-acetylmuramoyl-L-alanine amidase (mucopeptide amidohydrolase, EC 3.5.1.28) exists which splits the amide bond between the lactyl carboxyl group of the muramyl residue and the amino group of the peptide moiety in the peptidoglycan molecule.
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PMID:The metabolic fate of 14C-labeled immunoadjuvant peptidoglycan monomer. II. In vitro studies. 611 81

The enzyme N-acetylmuramyl-L-alanine amidase (mucopeptide amidohydrolase, EC 3.5.1.28) has been detected in human, mouse, rabbit, bovine and sheep sera. A method for detection of amidase activity using [14C]peptidoglycan monomer as the substrate has been developed. Partial purification of human and mouse amidase was achieved by gel chromatography on Bio-Gel A-1.5 m, DEAE-Sephadex A-50 and Sephadex G-100. Both amidase preparations exhibited maximal activity at pH 9.0 in Tris-HCl buffer and required Mg2+ for maximal activity. Following digestion of peptidoglycan monomer, GlcNAc-MurNAc-L-Ala-D-isoglutaminyl-meso-diaminopimelyl-D-Ala-D-Ala, the disaccharide GlcNAc-MurNAc and the corresponding pentapeptide L-Ala-D-isoglutaminyl-meso-diaminopimelyl-D-Ala-D-Ala were formed and subsequently isolated and chemically characterized. The enzyme therefore acts as an N-acetylmuramyl-L-alanine amidase by cleaving the bond between N-acetylmuramic acid and L-alanine. The glycan linked, peptide-not-cross-linked peptidoglycan dimer was also shown to be a substrate for human and mouse amidase.
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PMID:Partial purification and characterization of N-acetylmuramyl-L-alanine amidase from human and mouse serum. 612 7