GLYCOLYTIC PH OSCILLATIONS IN A FLOW REACTOR

A new type of flow reactor (UCSTR) has been developed that uses anisotropic ultrafiltration membranes in a continuous flow stirred tank reactor (CSTR) to facilitate the study of nonlinear enzyme catalyzed reactions. The design allows the study of enzymes with subunit molecular weights greater than or equal to 9000 dalton and protein concentrations up to at least 2 mg/ml under flow conditions with a residence time of 3 min or more, in a reactor of volume 1.67 mi. The UCSTR allows continuous potentiometric or spectrophotometric measurement without design change. Calibration of reactor performance was carried out by reproducing pH oscillations in the ferrocyanide-hydrogen peroxide reaction. Experimental verification of oscillatory glycolysis in the UCSTR was carried out with extract of rat skeletal muscle. Input feeds were fructose-6-phosphate and ATP with low concentrations of phosphate as buffer. Oscillations in pH, sustained for over eight hours, were observed. A six-step mechanism, including product activation and substrate inhibition, seven concentration variables, and four enzymes sufficed to simulate the pH oscillations observed in the UCSTR.