ERYTHROCYTE METABOLISM. V. LEVELS OF GLYCOLYTIC ENZYMES AND REGULATION OF GLYCOLYSIS*

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Abstract
A method is described for the preparation of erythrocyte suspensions in which the inherent pH of the cells may be adjusted to any desired value in the region of 6. 4 to 9. 4; the pH is maintained during glycolysis for a period of 3 hours at 37[degree]. In the intact cell, maximum production oflactate (6. 5 [mu]M/per hour per ml of red cells) from glucose was achieved at pH 8. 1 with an extracellular con-centration of inorganic phosphate of 0. 03 M. When glycolysis is recon-structed in an hemolysate system, fortified with ATP, DPN, inorganic phosphate, and Mg++, the pH optimum and the rate of lactate production are the same as observed for the intact erythrocyte. Lactate production in the hemolysate is inhibited by Na+, HPO4=, and Tris+. The levels of the individual glycolytic enzymes have been determed in the hemolysate at pH 8.1. These findings are discussed with reference to the over-all glycolytic rate and are correlated with the steady-state levels in the cell of ADP, ATP, inorganic phosphate, and phosphorylated intermediates of glycolysis.