Question

In the thin filament of skeletal muscle fiber, a small globular protein that masks the active sites on the actin, is

• A. G-actin
• B. Actin
• C. Tropomyosin
• D. Troponin
• E. Myosin

Answer 1

The correct option is D Troponin

The thin filament of skeletal muscle fiber is composed of three distinct proteins, i.e. actin, tropomyosin, and troponin. Troponin inhibits the actin-myosin interaction. The binding of calcium to the troponin unmasks the myosin binding active sites on actin. Tropomyosin is a fibrous molecule that attaches to actin in the groove between its filaments. G-actin is the monomer of the actin filament.