title: LD-carboxypeptidase activity in Escherichia coli. I. The LD-carboxypeptidase activity in ether treated cells.
abstract: The activities of the LD-carboxypeptidases of Escherichia coli K 12 and of a mutant strain 155 with reduced activities were studied with the aid of ether treated cells. Evidence was obtained that was consistent with the suggestion that in both strains two LD-carboxypeptidase activities are present. Activity I degrades the nucleotide activated precursor UDP-MurNAc-tetrapeptide and activity II splits off D-alanine residues from position 4 of the peptide subunits in the nascent murein. In the mutant strain activity I is reduced 10fold compared with strain K 12, whereas activity II is not affected. The two activities could be distinguished with regard to their sensitivity to D-amino acids and the beta-lactam antibiotic thienamycin.
mesh_terms: D000409:Alanine / Q000378:metabolism; D000596:Amino Acids / Q000494:pharmacology; D002268:Carboxypeptidases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D004986:Ether / Q000494:pharmacology; D009154:Mutation; D010457:Peptidoglycan / Q000096:biosynthesis / Q000378:metabolism; D013845:Thienamycins / Q000494:pharmacology; D014538:Uridine Diphosphate N-Acetylmuramic Acid / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D000596:Amino Acids; D010457:Peptidoglycan; D013845:Thienamycins; D014538:Uridine Diphosphate N-Acetylmuramic Acid; D004986:Ether; C002225:UDP-N-acetylmuramic acid pentapeptide; D002268:Carboxypeptidases; C021505:LD-carboxypeptidase; D000409:Alanine