Inhibition of protein synthesis by glucose 6-phosphate and fructose 1,6-diphosphate in lysed rabbit reticulocytes and the reversal of inhibition by NAD+.

Glucose 6-phosphate and fructose 1,6-diphosphate inhibit protein synthesis when added to lysed rabbit reticulocytes. Protein synthesis is inhibited 47% with 6 mM fructose 1,6-diphosphate and 86% with 6 mM glucose 6-phosphate. With 0.125 mM NAD⁺, the inhibitory effect of glucose 6-phosphate and fructose 1,6-diphosphate becomes stimulatory. The stimulation of protein synthesis in those assays with NAD⁺ and the phosphorylated sugars is 50% above those assays that contain NAD⁺ alone. The inhibition of protein synthesis by glucose 6-phosphate and the reversal of this inhibition by NAD⁺ occurs at a step before the synthesis of the initial dipeptide, methionyl-valine. These data illustrate the importance of NAD⁺ and the activation of glycolysis in regulating protein synthesis in lysed rabbit reticulocytes.