KINETIC PROPERTIES OF PHOSPHOFRUCTOKINASE IN THE MUCOSA OF MOUSE AND RAT SMALL INTESTINE

The regulatory properties of mouse jejunal mucosa phosphofructokinase have been studied in crude extracts freed from low molecular weight effectors on Sephadex G-100, and compared to those of the rat. Both isoenzymes displayed cooperativity with respect to fructose 6-phosphate at pH 7.0 in the presence of inhibitory concentrations of ATP. The rat isoenzyme was activated to a greater extent by AMP and P, and inhibited to a greater extent by creatine phosphate than the mouse isoenzyme. Both isoenzymes were strongly activated by glucose 1,6-diphosphate and strongly inhibited by citrate. The general similarity in properties of the two isoenzymes reflects the fact that both rat and mouse intestinal mucosa are characterised by high rates of aerobic glycolysis.