Isolation of a rat ventral prostate chromatin fraction exhibiting a singular melting profile

Rat ventral prostate chromatin, prepared by a gentle procedure in which marked shearing forces were avoided, was separated by sucrose gradient centrifugation into a quantitatively minor less dense (L) fraction, and 2 heavier components, (H₁) and (H₂). The (L) fraction, comprising 5–15 percent of the totäl chromatin DNA, had a unique melting profile, with a Tm_app. of 59°, compared to 82.5°, 85° and 80.5° for total, (H₁) and (H₂) chromatin. (L) chromatin has a number of other properties expected of “euchromatin”. This approach to the preparation of chromatin has been used successfully with other tissues such as liver.