dd -Carboxypeptidase and Peptidoglycan Transpeptidase from Pseudomonas aeruginosa

Abstract
Peptidoglycan transpeptidase and dd -carboxypeptidase have been detected in isolated membranes of Pseudomonas aeruginosa . Cephalosporins and penicillins fail to inhibit the transpeptidase at concentrations as high as 100 μg/ml. dd -Carboxypeptidase, on the other hand, is sensitive to inhibition by β-lactam antibiotics. The presence of dimethyl sulfoxide in the reaction mixture results in a twofold stimulation of peptidoglycan formation, whereas dd -carboxypeptidase is inhibited approximately 30%. Maximum stimulation of transpeptidase occurs in the presence of both dimethyl sulfoxide and a β-lactum antibiotic. This is in sharp contrast to the transpeptidase from Escherichia coli , which is sensitive to inhibition by penicillins and cephalosporins.