CDC123, as known as D123, belongs to the CDC123 family. This protein is expressed in spleen, thymus, prostate, testis, ovary, small intestine, colon and leukocytes with the highest expression in testis. CDC123 is required for S phase entry of the cell cycle. Recombinant human CDC123 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography.