Acetylation and Methylation of Histones in Pernicious Anemia

Acetylation and methylation of erythroid histones was investigated in two patients with pernicious anemia before and after treatment with vitamin B₁₂ in vivo. It was found that vitamin B₁₂ facilitated both acetylation and methylation of histones. Electrophoresis of amino acids obtained from histone hydrolysates prior to treatment with vitamin B₁₂ demonstrated that lysine was present as I-lysine. After treatment with vitamin B₁₂, most of the lysine appeared as methyl-I-lysine. Whether this biochemical lesion is specific for vitamin B₁₂ deficiency or also occurs in folic acid deficiency awaits future studies.