Analytical study of the degradation of nucleohistone during calf thymus chromatin autolysis.

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 (10(5)) 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.