P-Fructokinase and the control of the citric acid cycle

Abstract

It was reported earlier (Passonneau and Lowry, 1962a, 1962b) tha the strange kinetic properties of P-fructokinase (PFK) provide a reasonable explanation for the control of glycolysis beyond fructose6-p (FOP). PFK is strongly inhibited by high levels of one substrate ATP (Lardy and Parks (1956), Bueding and Mansour (1957), Mansour and Mansour (1962)), and this inhibition is counteracted by the other substrate and both products as well as by AMP, Pi, and cyclic 3',5fAMP.1 Increases in activity of 10 or 20-fold are produced by small increases in these compounds , and combinations of some of them are particularly effective. These results have been confirmed for heart PFK (Mansour, 1963); and yeast PFK has been shown to exhibit a number of the same kinetic phenomena (Vi&&la et al., 1963).