Histone deacetylase from calf thymus

Abstract

1. 1. An enzyme activity which catalyzed the deacetylation of histone was found in calf thymus extract. 2. 2. [ 14C]Acetyl-labeled histone, prepared by incubating calf thymus nuclei with sodium [ 14C]acetate, served as substrate and treatment of the histone with pronase destroyed most of the susceptibility to the enzymatic deacetylation. [ 14C]-Acetyl-labeled histone prepared by chemical acetylation with [ 14C]acetic anhydride served as substrate to a lesser extent. 3. 3. The enzyme had a pH optimum at 7.0. 4. 4. The enzyme reaction was inhibited by sulfhydryl reagents. 5. 5. Chromatographic profile on DEAE-cellulose indicated the multiplicity of the enzyme. Large molecular weight of the enzyme was indicated by the gel filtration on Sephadex G-200. 6. 6. Most of the enzyme activity was found in the soluble fraction rather than in the nuclear fraction. 7. 7. The mouse liver extract had little deacetylase activity and had an inhibitory effect on the deacetylation reaction by calf thymus extract.