COENZYME PRODUCTION USING IMMOBILIZED ENZYMES .3. IMMOBILIZATION OF GLUCOSE-6-PHOSPHATE-DEHYDROGENASE FROM BAKERS-YEAST

Glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate:NADP(+) 1-oxi doreductase, EC 1.1.1.49) from Bakers' yeast was immobilized with the highest activity on polyacrylamide beads possessing carboxylic functio nal groups activated by a water-soluble carbodiimide. The optimal pH v alues for the catalytic activity of the soluble and the immobilized gl ucose-6-phosphate dehydrogenase were practically identical lying betwe en pH 9.0 and 9.2. The optimal temperature for both the soluble and th e immobilized enzyme was about 50 degrees C. The apparent K-m values o f the immobilized enzyme were slightly higher than those of the solubl e enzyme. The immobilization improved the stability of the enzyme in t he pH range 6.0-9.0 at 45 degrees C. The operational stability of the immobilized glucose-6-phosphate dehydrogenase proved favorable in a co lumn experiment during 37 days of operation.