Melting from both ends of an A-band in a myofibril. Observation with a phase-contrast microscope.

Observation with a phase-contrast microscope clearly shows that melting of an A-band, i.e., a bundle of thick (myosin) filaments, in a rabbit skeletal myofibril occurs from both ends in the pressure of high concentrations of KCl and PPi. Thick filaments partially melted from both ends can be obtained in a myofibril.