title: The penicillin-binding site in the exocellular DD-carboxypeptidase-transpeptidase of Actinomadura R39.
abstract: Heat denaturation and Pronase degradation of the complex previously formed between benzylpenicillin and the exocellular DD-carboxypeptidase-transpeptidase of Actinomadura R39 yields a heptapeptide H-Leu-Pro-Ala-Ser-Asn-Gly-Val-OH, where the benzylpenicilloyl group is ester-linked to the serine residue. This linkage is very labile and its hydrolysis causes the release of benzylpenicilloate. In contrast, the native benzylpenicilloyl-enzyme complex is very stable (half-life 70 h at 37 degrees C) and its breakdown proceeds via fragmentation of the bound benzylpenicilloyl group [Fuad, Frère, Ghuysen, Duez & Iwatsubo (1976) Biochem. J. 155, 623-629].
mesh_terms: D000595:Amino Acid Sequence; D044482:Benzeneacetamides; D001665:Binding Sites; D002268:Carboxypeptidases; D004586:Electrophoresis; D006358:Hot Temperature; D002267:Muramoylpentapeptide Carboxypeptidase; D009618:Nocardiaceae / Q000201:enzymology*; D009842:Oligopeptides; D010400:Penicillin G / Q000031:analogs & derivatives*; D010446:Peptide Fragments / Q000032:analysis; D011489:Protein Denaturation; D014357:Trypsin
chemical_list: D044482:Benzeneacetamides; D009842:Oligopeptides; D010446:Peptide Fragments; C032648:benzylpenicilloyl-heptapeptide; D002268:Carboxypeptidases; D002267:Muramoylpentapeptide Carboxypeptidase; D014357:Trypsin; D010400:Penicillin G