Mediates the deacetylation of lysine residues on the N-terminal part of the core histones (H2A, H2B, H3 and H4). Histone deacetylation gives a tag for epigenetic repression and plays an important role in transcriptional regulation, cell cycle progression and developmental events. Able to deacetylate all 4 core histones. Inhibited by 3-(4-Aroyl-1-methyl-1H-pyrrol-2-yl)-N-hydroxy-2-propenamides. 3-(1-methyl-4-phenylacetyl-1H-pyrrol-2-yl)-N-hydroxy-2-propenamide 1b and 3-[1-methyl-4-(3-phenyl-2-propenoyl)-1H-pyrrol-2-yl]-N-hydroxy-2-propenamide 1c are very potent inhibitors. Optimum pH is 7.5. Multimer. Isolated as a trimer composed of 3 proteins of 39, 42 and 45 kDa, possibly a homotrimer with different phosphorylation status or a heterotrimer with HDT2 and/or HDT3. Expressed throughout germination. Increases during the initial 30 hours of germination, slightly decreases between 30 and 48 hours, and increases again at 60 hours, correlating with the proliferative activity of embryo cells. The N-terminus is blocked. Phosphorylated. Required for enzyme activity. Belongs to the histone deacetylase HD2 family.