Pharmacological studies on carbapenem antibiotics. II. Isolation of a PS-5-inactivating factor from the rat kidney.

A factor responsible for the in vivo metabolism of PS-5 was isolated from the microsomal fraction of the rat kidney. This factor, which did not attack penicillins and cephalosporins, was enzymologically identified with particle-bound renal dipeptidase. Under the action of this factor, PS-5 was inactivated to give three products designated PS-5D I, PS-5D II and PS-5D III.