HUMAN SEMINAL PLASMA ZN-ALPHA-2-GLYCOPROTEIN - ITS PURIFICATION AND PROPERTIES AS COMPARED WITH HUMAN PLASMA ZN-ALPHA-2-GLYCOPROTEIN

On the basis of the datum that the level of Zn-β2-glycoprotein (Znα2gp) in human seminal plasma was about 6-times higher than that in adult serum, Znα2gp was purified from fresh human seminal plasma approx. 70-fold with 60% yield over seminal plasma by DEAE-Sephacel, Zn-chelate Sepharose 4B and DEAE-5PW column chromatographies. The molecular weight of seminal plasma Znα2gp was 50 000 on Superose column chromatography, and 40 500 and 41 500 on SDS-polyacrylamide gel electrophoresis in the absence and presence of β-mercaptoethanol, respectively. Plasma Znα2gp is a glycoprotein, while the protein from seminal plasma does not contain carbohydrate. The amino acid sequence of the first 17 residues of seminal plasma Znα2gp was Glu-Asn-Gln-Asp-Gly-Asn-Tyr-Ser-Leu-Thr-Tyr-Ile-Tyr-Thr-Gly-Leu-Ser. This sequence was completely identical with the amino acid residues from Glu-2 to Ser-18 in the N-terminal amino acid sequence of plasma Znα2gp. These data suggest that bot Znα2gps in plasma and seminal plasma may be expressed from one gene, but their posttranslational modifications are different. © 1990.