Tropomyosin is a member of the actin filament binding protein family. It is a ubiquitous protein present in animals and fungi. Tropomyosin is made up of two α-helical chains arranged as a coiled-coil. It exists over twenty isoforms, in different eukaryotic cells like skeletal, cardiac, and smooth muscles, brain, platelets, fibroblasts, platelets, and other non-muscle cells.

Tropomyosin from porcine muscle has been used:

• as a positive control in actin- α-tropomyosin (TPM1) co-sedimentation analysis and assay
• in analyzing the anti-adhesive properties of fish tropomyosins
• in far Western blot analysis

Dimeric protein that assumes an α-helical coiled coil conformation. In the absence of Ca²⁺, inhibits muscle contractility by blocking the myosin binding sites on actin.

Tropomyosin is associated with the actin cytoskeleton and plays a role in stabilizing and regulating the interactions of actin with other actin-binding proteins. It also plays a role in muscle contraction by regulating the interactions of actin with myosin.

Tropomyosin together with troponin, regulates the binding of myosin to actin. Tropomyosin is a dimeric coiled-coil protein forming continuous polymers along the myosin-binding groove of actin. Various tropomyosin isoforms help confer structure and function to actins in the cytoskeleton and striated muscle function. Dimeric protein that assumes an α-helical coiled-coil conformation. In the absence of Ca2+, it inhibits muscle contractility by blocking the myosin binding sites on actin.

SDS electrophoresis shows two major bands.