HPGDS, also known as GSTS, is a sigma class glutathione-S-transferase family member. The enzyme catalyzes the conversion of PGH2 to PGD2 and plays a role in the production of prostanoids in the immune system and mast cells. The presence of this enzyme can be used to identify the differentiation stage of human megakaryocytes. Recombinant human HPGDS protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.