Isolation of yeast nuclei. Evidence of chromatin-associated proteolytic activity.

Purified yeast nuclei contain proteolytic activities which are associated with chromatin. pH optimum is in the range 8.0--8.5. Partial purification reveals the presence of three fractions corresponding to different molecular weights. Boiled chromatin supernatants are able to inhibit proteolytic activity. The inhibition effect of various compounds is also described. The purity of the chromatin preparation seems to rule out artifacts due to contamination.