The mechanism of nucleohistone degradation in calf thymus chromatin during autolysis of the latter involves a release of lysine-rich histone fractions, followed by degradation of the thus-exposed DNA portions; the latter portions are richest in adenine–thymine sequences. After this degradation process, residual nucleohistone fragments of low molecular weight (105) remain. Their chemical composition is special, in that the DNA contains a larger proportion of guanine–cytosine sequences than does the initial DNA and it is combined with arginine-rich histones.
