Amino acid sequence of troponin C obtained from ascidian (Halocynthia roretzi) body wall muscle.

The amino acid sequence of ascidian troponin C has been determined. It is composed of 155 amino acid residues and contains two tryptophan residues which have not been found in other troponin C sequences so far determined. The N-terminus is acetylated, and the molecular mass was calculated to be 17,794. Calcium binding sites I and III of ascidian troponin C appear to have lost the ability to bind calcium, and the total number of binding sites is reduced to two.