(Science: enzyme) An enzyme that catalyses the hydrolysis of myosin aTP in the presence of actin to form myosin aDP and orthophosphate. This reaction is the immediate source of free energy that drives muscle contraction. In the absence of actin, myosin atpase activity is low and requires calcium ions.
Chemical name: Myosin ATP phosphohydrolase (actin-translocating)
Registry number: EC 18.104.22.168