BIOCHEMICAL-CHARACTERIZATION OF THE 49 KDA PENICILLIN-BINDING PROTEINOF MYCOBACTERIUM-SMEGMATIS

The 49 kDa penicillin-binding protein (PBP) of Mycobacterium smegmatis catalyses the hydrolysis of the peptide or S-ester bond of carbonyl d onors R(1)-CONH-CHR(2)-COX-CHR(3)-COO- (where X is NH or S). In the pr esence of a suitable amino acceptor, the reaction partitions between t he transpeptidation and hydrolysis pathways, with the amino acceptor b ehaving as a simple alternative nucleophile at the level of the acyl-e nzyme. By virtue of its N-terminal sequence similarity, the 49 kDa PBP represents one of the class of monofunctional low-molecular-mass PBPs . An immunologically related protein of M(r) 52000 is present in M. tu berculosis. The 49 kDa PBP is sensitive towards amoxycillin, imipenem, flomoxef and cefoxitin.