Acetylation of Histones by a Calf Thymus Enzyme Studies on the Sites of Acetylation

Abstract

A histone acetylating enzyme was extracted from the cytoplasmic fraction of calf thymus and the sites in histone acetylated by the enzyme were studied. Acetylation of ɛ-amino group of lysyl residues of histone was catalyzed by the enzyme and the introduced acetyl groups were susceptible to histone deacetylase. The reaction of this enzyme appears to be like that occurring in the isolated nuclei. However, the enzyme of cytoplasm significantly acetylated only a particular histone species, f2al, while both f2al and f3 histones were acetylated in the isolated nuclei.