ATP utilization associated with recovery metabolism in anaerobic frog muscle.

The ATP turnover during single isometric 0.5-, 1-, and 3-s tetani in anaerobic frog sartorii was measured at 20 degrees C. In parallel experiments, we measured the lactate production by sartorii during their metabolic recovery from such tetani. From these measurements, we obtained an experimental P/lactate ratio which was less than 1.5, the expected value for simple Embden-Meyerhof glycolysis when glycogen is metabolized to lactate. We interpreted these results as indicating a substantial amount of suprabasal ATP breakdown occurred during metabolic recovery. The operation of the fructose phosphate substrate cycle is suggested as a cause of this additional ATP breakdown.