[Location of adenine nucleotides in striated fibers of skeletal muscles].

The absorption of light at 265 nm wave length in isolated muscle fibers and myofibrilles of vertebrate striated muscle was investigated with the aid of microscope with the wide spectral range (240--900 nm), equipped with image intensifier and recording cine camera. It was established that freshly isolated nonfatigue frog fibers absorbed UV-light along the entire of the length of the fiber. This fact attests the uniform distribution of ATP and some other nucleotides in the myoplasma of muscle cell. The fatigue of the fibers results in the appearance of a cross--striated pattern along the length of fiber, determinated by the alternation of the sarcomere regions with different degree of light absorption at the given wave length. The regions of the most heavily absorption of UV corresponds to the I-, M-, and N-bands of sarcomere. The comparison of the data obtained from intact and glycerinated fibers and also from myofibrilles with extracted A-bands allows to suppose that the absorption bands at 265 nm wave length are the places of location of bound ADP, RNA and minor fraction of ATP.