Serine (or cysteine) proteinase inhibitor clade B (ovalbumin) member 5, also known as Maspin, is a tumor suppressor protein of serine proteinase inhibitor family. It plays an essential role in embryonic development through critical roles in cell adhesion. Also, it is present in normal breast and prostatic epithelial cells but downregulated in the respective carcinomas. Recombinant human Maspin, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography.