The role of ATPase in glycolysis of Ehrlich ascites tumor cells.

Glycolysis in Ehrlich ascites tumor cells suspended in buffer containing 5 mM Pi was 50% inhibited by ouabain. In the absence of Pi the inhibition was less striking. Permeabilization of the cells with filipin abolished glycolysis, but glycolysis was restored by addition of Pi and AMP. Neither ouabain nor quercetin inhibited glycolysis in these permeabilized cells. We conclude that quercetin did not inhibit hexokinase sufficiently to affect glycolysis. An extract of Ehrlich ascites tumor cells glycolyzed weakly unless either Pi or an ATPase (e.g. (Na+K+)-ATPase) was added. The low rate of glycolysis of the extract was even further reduced when an endogenous ATPase was removed by precipitation with CaATP. The glycolytic activity of this ATPase-deficient extract was restored by addition of purified (Na+K+)-ATPase or of CaATP-precipitable ATPase. Addition of hexokinase without Pi did not restore glycolytic activity to the extract. An explanation for the contradictory conclusions by Bustamante, E., Morris, H.P., and Pedersen, P.L. (J. Biol. Chem. (1981) 265, 8699-8704) is presented.