Effect of troponin T-treatment on the composition of rabbit skeletal myofibrils.

The effect of several conditions of troponin T-treatment was examined on the SDS-gel electrophoretic patterns of rabbit skeletal myofibrils. More troponin C and I were removed from the myofibrils after troponin T-treatment at acidic pH (5.6-6.2) than after treatment at neutral pH (6.8-7.4). Incubation of the myofibrils (0.4 mg/ml) in the presence of 0.043 mg/ml troponin T at a pH 6.2 for 60 min at 25 degrees C resulted in the removal of most troponin C and I from the myofibrils. Troponin T1 (N-terminal 158 residue fragment of troponin T of 259 residues) showed much lower troponin C.I removing activity than troponin T.