Slowly hydrolyzes 6-aminopenicillinic acid and 7-aminocephalosporanic acid (ACA) derivatives. May be involved in the synthesis of the cell wall peptidoglycan (By similarity). a beta-lactam + H2O = a substituted beta-amino acid Inhibited by cloxacillin and oxacillin but not by ACA derivatives or metal chelators. Belongs to the hcp beta-lactamase family.