Solubilization and Isolation of the Membrane-Bound dd-Carboxypeptidase of Streptococcus faecalis ATCC 9790. Properties of the Purified Enzyme

Abstract

S. faecalis ATCC 9790 possesses 6 membrane-bound, penicillin-binding proteins. That numbered 6 (MW 43,000) is the most abundant one and is the DD-carboxypeptidase [EC 3.4.12.6] studied previously. The enzyme was solubilized and purified to the stage where 1 single protein band can be detected by gel electrophoresis. The purification procedure does not alter the properties the enzyme exhibits when it is membrane-bound. The DD-carboxypeptidase itself may be a killing target for penicillin in S. faecalis.