Crystalline bacterial penicillinase

Abstract

Penicillinase was isolated from the culture supernatant fluid of a Bacillus cereus mutant which forms large amounts of the enzyme constitutively. The enzyme was crystallized after fractionation with ammonium sulfate and precipitation with 40% ethanol. Ultracentrifugal and electrophoretic analysis of the purified enzyme indicates that it consists of a single species of protein with an isoelectric point a little above pH 5.0, and a molecular weight of 35,200. The enzyme is stable on dialysis, and there is no indication of the presence of any characteristic prosthetic group or need for a co-enzyme or other specific activator.