Answer
Three important functions of ATP in the process of skeletal muscle contraction :
1. The ATP molecule supplies the energy for activation of the myosin head which facilitates binding of actin.
2. It binds to myosin and causes its detachment after the power stroke.
3. In excitation-contraction coupling, ATP powers the protein pump that transports Ca++ from the sarcoplasm back into the sarcoplasmic reticulum. This transport of Ca++ is necessary for the propagation of action potentials along T-tubules
Work Step by Step
ATP is a source of chemical energy which is released by hydrolysis catalyzed by ATPase enzyme.
It supplies the energy that enables the myosin head to bind to the actin molecule in preparation for
the power stroke which in contraction.
After the power stroke, the myosin head ( and ADP, and PO4) must be detached from the actin binding site. ATP binds to myosin and causes its detachment from actin-- after the power stroke.
ATP also powers the protein pump that transports calcium from the sarcoplasm back to the sarcoplasmic reticulum. These Ca++ ions are necessary for the propagation of muscle action potentials along T-tubules.
