Penicillin is hydrolyzed and thereby rendered inactive by penicillinase (also known as b-lactamase), an enzyme present in some penicillin- resistant bacteria. the mass of this enzyme in staphylococcus aureus is 29.6 kd. the amount of penicillin hydrolyzed in 1 minute in a 10-ml solution containing 1029 g of purified penicillinase was measured as a function of the concentration of penicillin. assume that the concentration of penicillin does not change appreciably during the assay.