
%0 Journal Article
%A Burnell, JN 
%A Jenkins, CLD 
%A Hatch, MD 
%T Regulation of C<sub>4</sub> Photosynthesis A Role for Pyruvate in Regulating Pyruvate,P<sub>i</sub> Dikinase Activity <i>in vivo</i>
%J Functional Plant Biology
%D 1986/04/01
%V 13
%N 2
%P 203-210
%K 
%R https://doi.org/10.1071/PP9860203
%U https://www.publish.csiro.au/paper/PP9860203 
%X Results are presented in support of the view that pyruvate levels are critical in the light-dark regulation of pyruvate,PI dikinase in vivo. In an in vitro system containing purified Zea mays pyruvate,PI dikinase, increasing pyruvate reduced both the initial rate and the final extent of ADP-mediated inactivation of the enzyme. Pyruvate also reversed the inhibitory effect of ADP on the initial rate of PI-mediated activation of pyruvate,P*i dikinase. With intact Zea mays leaves, inactivation of pyruvate,PI dikinase in darkened leaves was prevented by anaerobic conditions or reduced temperature; both treatments resulted in elevated steady-state levels of pyruvate. Added pyruvate was shown to substantially increase the level of active pyruvate,PI dikinase in chloroplasts incubated with PI in the dark but not in the light. The likely physiological significance of these results is discussed. 
