Preparation of three troponin components from puffer skeletal muscle.

The Ca(2+)-regulatory proteins, i. e., troponin C, I and T, were prepared from puffer skeletal muscle. The SDS-gel electrophoretic study indicated that the molecular weights of troponin C, I and T were 18, 20 and 30k daltons, respectively. The Ca(2+)-sensitivity of the ATPase activity of the puffer myofibrils was abolished by the removal of troponin C by the CDTA-treatment and then restored by the reconstitution with puffer skeletal troponin C. The treatment with excess troponin T of either puffer or rabbit skeletal muscle at slightly acidic condition resulted in the removal of troponins C and I from the puffer myofibrils. The reconstituted puffer troponin C-I-T gave the Ca(2+)-sensitivity to the ATPase activity of puffer desensitized myofibrils in the presence tropomyosin.