Acid-extracted glycoproteins in human seminal coagulum.

Protein in intact coagulum of fresh human ejaculate was extracted by 0.25 N HCl, the condition used for extraction of sperm basic proteins. About 75% of the total coagulum protein was found to be acid-extractable and therefore so-called coagulum basic proteins (CBP). The CBP were glycosylated and entirely distinguishable from sperm protamine in many aspects. The CBP consisted of two major components as analyzed by acid-urea polyacrylamide gel electrophoresis (PAGE). However sodium dodecyl sulfate-PAGE could resolve the CBP into 3 main components with apparent molecular weights of 52,000, 80,000 and 82,000 daltons respectively. Dissolution of the CBP during in vitro liquefaction of the fresh ejaculate suggested the possible role of the glycoprotein in the coagulum structure.