What is the role of the globular head in the heavy meromyosin (HMM)...

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 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 globular head in the HMM component is an active ATPase enzyme and has binding sites for ATP and active sites for actin.