What is the main function of the heavy meromyosin (HMM) component?

.Each "F" actin is a polymer of monomeric "G" (Globular) actinsTwo filaments of another protein, tropomyosin also run close to the "F" actins throughout its length.In the resting state a subunit of troponin masks the active binding sites for myosin on the actin filaments.The thick filament in a myofibril is made up of many monomeric proteins called Meromyosins.The HMM component consists of the head and short arm of a meromyosin.The cross arm in the HMM component refers to the head and short arm projecting outwards at regular distance and angle from each other from the surface of a polymerised myosin filament.The light meromyosin (LMM) component refers to the tail of a meromyosin.The main function of the HMM component is to act as an ATPase enzyme and has binding sites for ATP and active sites for actin.