The Peptidoglycan Crosslinking Enzyme System in Streptomyces Strains R61, K15 and rimosus

Abstract
The DD-carboxypeptidase-transpeptidase enzyme system in Streptomyces strain K15 consists of a membrane-bound transpeptidase capable of performing low DD-carboxypeptidase activity, and a set of DD-carboxypeptidases: membrane-bound, lysozyme-releasable and exocellular, having low transpeptidase activities in aqueous media and at low acceptor concentrations. The DD-carboxypeptidases are related to each other and may belong to the same pathway leading to enzyme excretion. A similar enzyme system occurs in Streptomyces strain R61 except that the membrane-bound DD-carboxypeptidase activity is low when compared with the membrane-bound transpeptidase activity. In S. rimosus the enzyme system consists almost exclusively of the membrane-bound transpeptidase and the levels of membrane-bound, lysozyme-releasable and exocellular DD-carboxypeptidases are very low.