Penicillin is hydrolyzed and thereby rendered inactive by penicillinase, an enzyme present in some 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 10^-9 g of purified penicillinase was measured as a function of the concentration of penicillin. A plot of 1/V_0 versus 1/[S] indicated the V_max=6.8 times^- 10 mol minute^-1. Assuming one active site per enzyme molecule, the turnover number for penicillinase is (A) 337 s^-1
(B) 337 min^-1
(C) 600 hour^-1
(D) 33 hour^-1 600 s^-1
. A closed system allows only energy transfer but no transfer of mass. Example: a cup of coffee with a lid on it, or a simple water bottle. ... In reality, a perfectly isolated system does not exist, for instance hot water in a thermos flask cannot remain hot forever.