PURIFICATION AND PROPERTIES OF PENICILLIN BETA-LACTAMASES MEDIATED BY TRANSMISSIBLE R FACTORS IN ESCHERICHIA COLI

1. Two types of penicillin β-lactamases [EC 3.5.2.6], penicillinase,88 and penicillinase14, were isolated from E. coli harboring transmissible R factors, RGN235 and RGN14 respectively, and purified mainly by means of column chromatography. Penicillinase238 belonging to type II-penicillinases was purified about 158 fold, and penicillinase14, which is one of type I-penicillinases was purified about 270 fold.2. Isoelectric point of penicillinase238 determined by agar gel electrophoresis was 8.3, and its s20, w was 2.66S. The optimal pH was around 7.6 and the optimal temperature was 30°C for the hydrolysis of benzylpenicillin.3. With respect to penicillinase14 the isoelectric point was 5.1 and the value of s20, w was 1.43S in the synthetic boundary cell. The maximal enzyme activity to benzylpenicillin was observed at 45°C and at pH 6.5.4. The difference between the two enzymes was also revealed by the behaviors to anions like chloride and the kinetic aspects (Km and Vmax). © 1969 BY THE JOURNAL OF BIOCHEMISTRY.