Balance of ATP consumption of reticulocytes.

The sum-total of ATP produced amounts to 135 mmoles X 1 reticulocytes-1 X hour-1. About 70% of the ATP consumption has been accounted for by specific processes. The main contributing processes are: the globin synthesis with about 28%; the Na+/K+-ATPase with 23%, and the ATP-dependent share of proteolysis with more than 15%. 30% of ATP consumption has not been accounted for. Cycloheximide (20 X 10(-6) M) leads to a dissociation between synthesis and degradation of proteins, which argues against any obligatory connection between these processes. About 90% of the lysine liberated from mitochondria by proteolysis were reutilized for the globin synthesis demonstrating the high nitrogen economy of reticulocytes. Each of the ATP consuming processes studied appears to control ATP production in an independent manner without competition with each other.