The role of adenosine triphosphate in the phosphorylation of membrane components of chromaffin granules

Adenosine triphosphate acts on the ATPase of chromaffin granules of the adrenal medulla to release catecholamines, endogenous ATP, and soluble protein (Poisner and Trifaró, Mol. Pharmacol., 3: 572, 1967). In the present study, chromaffin granules were isolated by means of a new technique that consisted of an isotonic density gradient, which yielded a relatively pure fraction of granules suitable for in vitro studies. The distribution of the different subcellular organelles in the gradient was determined by different enzyme markers