Equilibrium between monomers and oligomers of soluble Ca2+-ATPase during the functional cycle

Molecular sieve HPLC shows that soluble sarcoplasmic reticulum Ca2+-ATPase at low concentrations of the non-ionic detergent octaethylene glycol monododecyl ether exists as monomers in equilibrium with dimers and higher oligomers. Binding of vanadate or ATP as well as phosphoenzyme turnover shifts the equilibrium towards the monomer. This suggests that the Ca2+-pump cycle can occur without transient self-association of Ca2+-ATPase peptides.