An Upper Limit for Acetylcholine Content and Synthesis in Human Erythrocytes. ∗

Abstract

Summary

The ACh content of human red cells is less than 0.08 γ/ml and no increase in synthesis can be observed in cells equilibrated with cholinesterase inhibitors. A synthetic rate higher than 6.3 γ/g/hr by acetone powders of red cells was not observed. There is some doubt that the activity observed was the result of enzymatic synthesis of ACh. Calculations show this rate to be less than 1/50 that required to provide the free energy essential for the accumulation of K against a concentration gradient. The metabolism of red cell Ach as a mechanism by which the cells accumulate K is of doubtful importance.