マガキのグルコース-6-リン酸脱水素酸素の精製と性質

抄録

Glucose 6-phosphate dehydrogenase, (EC 1. 1. 1. 49; Glc-6-P DH) in oyster Crassostrea gigas was extracted with 10mM Tris-HCl buffer solution and purified by ammonium sulfate fractiona-tion, Sepharose 6B gel filtration, and DEAE-Sephadex A-50, and CM-Sepharose CL-6B chromato-graphy. A single fraction exhibiting Glc-6-P DH activity was obtained by CM-Sepharose CL-6B chromatography. The purified Glc-6-P DH was electrophoretically homogenous. The optimal pH for hydrolysis of Glc-6-P was 8. The temperature which inactivated 50% of enzyme was 47°Cin 15-min treatment. The molecular weight was 204, 000. Beyond 35°C the activation energy of Glc-6-P DH was 5, 400 cal/mol, and below 35°C it was 10, 900 cal/mol. The enzyme was inhibited by Zn²⁺ and Hg²⁺ ions in low concentration and by Co²⁺ and Cu²⁺ ions in high concentration. How-ever, it can be activated by adding Ca²⁺, Mg²⁺, and Mn²⁺ ions in high concentration.