Question

The contractile protein of skeleton muscle involving ATPase activity is
A) α- Actinin
B) Troponin
C) Tropomyosin
D) Myosin

Answer 1

Our body is made of striated muscles, unstriated muscles, and skeletal muscles. The muscles are made up of different proteins that involve different functions of the body.

Complete answer:
To answer this question, we have to know details about the skeleton muscle. The skeleton muscle is made up of muscle fibers that have smaller units termed as myofibrils. The myofibrils are made of three proteins that are involved in contraction, structural proteins, and regulation. The contractile proteins have actin that is thin filament and myosin that is thick filament. Every actin filament is made of two helical ‘F’ actin and every ‘F’ actin is formed from multiple G actin. The ‘F’ actin along with the two filaments of regulatory proteins Troponin and Tropomyosin is also present. The Troponin covers the myosin binding sites on actin filaments during muscle relaxation. Every myosin consists of a meromyosin unit that has two important parts- the heavy meromyosin consists of a globular head with a short arm and a light meromyosin tail. The head of the molecules is composed of binding site of ATP and active site for actin.
Now, myosin is a molecule that involves the conversion of chemical energy into directed movement. The ability of the myosin is to utilize chemical energy as its ATPase activity. It causes ATP hydrolysis and uses the energy released from the hydrolysis of anhydride phosphate that result in muscle contraction.

Thus, the correct option is ‘D’. Myosin.

Note: The alpha actinin is a binding protein for actin the involved in non-muscular cells. The adherens-type junctions and the microfilament bundles found in the cytoskeleton isoform is involved in binding of actin to the membrane.