PAEP is a member of the kernel lipocalin super family whose members share relatively low sequence similarity but have highly conserved exon/intron structure and three-dimensional protein folding. Most lipocalins are clustered on the long arm of chromosome 9. This protein been previously referred to as pregnancy-associated endometrial alpha-2-globulin, placental protein 14, and glycodelin, but has been officially named progestogenassociated endometrial protein. Recombinant human PAEP protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.