GLYCOLYTIC PH OSCILLATIONS IN A FLOW REACTOR

A new type of flow reactor (UCSTR) has been developed that uses anisot ropic ultrafiltration membranes in a continuous flow stirred tank reac tor (CSTR) to facilitate the study of nonlinear enzyme catalyzed react ions. The design allows the study of enzymes with subunit molecular we ights 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 contin uous potentiometric or spectrophotometric measurement without design c hange. Calibration of reactor performance was carried out by reproduci ng pH oscillations in the ferrocyanide-hydrogen peroxide reaction. Exp erimental verification of oscillatory glycolysis in the UCSTR was carr ied out with extract of rat skeletal muscle. Input feeds were fructose -6-phosphate and ATP with low concentrations of phosphate as buffer. O scillations in pH, sustained for over eight hours, were observed. A si x-step mechanism, including product activation and substrate inhibitio n, seven concentration variables, and four enzymes sufficed to simulat e the pH oscillations observed in the UCSTR.