title: Specificity and reversibility of the transpeptidation reaction catalyzed by the Streptomyces R61 D-Ala-D-Ala peptidase.
abstract: The specificity of the Streptomyces R61 penicillin-sensitive D-Ala-D-Ala peptidase has been re-examined with the help of synthetic substrates. The products of the transpeptidation reactions obtained with Gly-L-Xaa dipeptides as acceptor substrates are themselves poor substrates of the enzyme. This is in apparent contradiction with the classically accepted specificity rules for D-Ala-D-Ala peptidases. The Gly-L-Xaa dipeptide is regenerated by both the hydrolysis and transpeptidation reactions. The latter reaction is observed when another Gly-L-Xaa peptide or D-Alanine are supplied as acceptors. Utilization of substrates in which the terminal -COO(-) group has been esterified or amidated shows that a free carboxylate is not an absolute prerequisite for activity. The results are discussed in the context of the expected reversibility of the transpeptidation reaction.
authors.affiliation: Centre d'Ingénierie de Protéines, Université de Liège, Institut de Chimie B6, Sart-Tilman, B-4000 Liège, Belgium.
authors.forename: Noureddine
authors.initials: N
authors.lastname: Rhazi
authors.forename: Michael
authors.initials: M
authors.lastname: Delmarcelle
authors.forename: Eric
authors.initials: E
authors.lastname: Sauvage
authors.forename: Françoise
authors.initials: F
authors.lastname: Jacquemotte
authors.forename: Kris
authors.initials: K
authors.lastname: Devriendt
authors.forename: Valérie
authors.initials: V
authors.lastname: Tallon
authors.forename: Léon
authors.initials: L
authors.lastname: Ghosez
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Frère
mesh_terms: D002384:Catalysis; D004151:Dipeptides / Q000737:chemistry / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D046929:Serine-Type D-Ala-D-Ala Carboxypeptidase / Q000737:chemistry* / Q000378:metabolism; D013302:Streptomyces / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D004151:Dipeptides; D010455:Peptides; D046929:Serine-Type D-Ala-D-Ala Carboxypeptidase