Occurrence of specific glycoprotein factor(s) in goat epididymal plasma that prevent adhesion of spermatozoa to glass.

Highly motile goat cauda-epididymal spermatozoa, when diluted markedly with a modified Ringer's solution, bind (approx. 100%) rapidly to the glass surface of haemocytometer. However, presence of epididymal plasma (EP, 2 mg protein/ml) in the dilution medium prevents nearly completely sticking of cells to the glass surface. The anti-sticking factor (ASF) of EP that prevents adhesion of spermatozoa to glass is nondialysable, heat-stable and sensitive to the action of trypsin. ASF is a glycoprotein that binds with high affinity to concanavalin a-agarose. EP-proteins (approx. 85%) that did not bind to the affinity column had little antisticking activity, indicating high protein specificity for ASF. Addition of exogenous Ca++ (1 mM) and Mg++ (4 mM) had no effect on the activity of ASF.