| troponin | <protein> Complex of three proteins, Troponins C, I, & T, associated with tropomyosin and actin on the thin filament of striated muscle, upon which it confers calcium sensitivity. There is one troponin complex per tropomyosin. Troponin C (18 kD) binds calcium ions reversibly, has a variable number of EF hand motifs and is the least variable of the subunits. TnC binds TnI & TnT, but not actin. Troponin I (23 kD) binds to actin and at 1:1 stoichiometry can inhibit the actin myosin interaction on its own. Troponin T (37 kD) binds strongly to tropomyosin. (18 Nov 1997) |
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| troponin c | One of the three polypeptide chains that make up the troponin complex. It is a calcium-binding protein. (12 Dec 1998) |
| troponin I | One of the three polypeptide chains that make up the troponin complex. It is an inhibitory protein that binds to actin. (12 Dec 1998) |
| troponin phosphatase | <enzyme> Dephosphorylates serine 20-phosphate of the inhibitor subunit tn-1, of cardiac troponin Registry number: EC 3.1.3.- (26 Jun 1999) |