Abstract
1. Two types of penicillin β-lactamases [EC 3.5.2.6], penicillinase238 and penicil-linase14, were isolated from E. coli harboring transmissible R factors, RGN238 and RON14 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 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 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).
