Mercurial-induced transformation of myosin prevented by adenosine triphosphate and pyrophosphate.

Adenosine triphosphate and pyrophosphate prevent the loss of Ca(//)-activated adenosine triphosphatase activity caused by high concentrations of mercurial sulfhydryl reagent. They concomitantly prevent the transformation of myosin into faster-sedimenting products. This is adduced as support for the hypothesis that the strategic sulfhydryl group is not binding adenosine triphosphate at the active site, but is initiating a conformational change upon its reaction with the mercurial reagent.