The centromere is a specialized chromatin domain, present throughout the cell cycle, that acts as a platform on which the transient assembly of the kinetochore occurs during mitosis. All active centromeres are characterized by the presence of long arrays nucleosomes in which CENPA replaces histone H3. CENPM is an additional factor required for centromere assembly. Recombinant human CENPM protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.