CHANGES IN THE MEMBRANE-PROTEINS OF BUCK (CAPRA-HIRCUS) SPERMATOZOA DURING EPIDIDYMAL MATURATION

Membrane proteins of the testicular cells/epididymal spermatozoa from goat bucks (Capra hircus) were extracted by detergents/proteases. The proportion of membrane proteins extracted were variable by Fast Protei n Liquid Chromatography (FPLC) and Polyacrylamide Gel Electrophoresis (PAGE). Proportion of negatively charged >70 kDa proteins, extractable by cetyltrimethyl ammonium bromide (CTAB) from testicular cell membra nes was lower than that extracted from epididymal spermatozoal membran es. Reverse was the case with positively charged >170 kDa proteins ext racted by sodium dodecyl sulphate (SDS). FPLC results show that the pr oportion of >170 kDa proteins with higher negative charge increases as the spermatozoa undergo epididymal maturation. The proportion of 35-1 70 kDa proteins extractable by deoxycholate were much less in the memb ranes of cauda spermatozoa. FPLC showed predominance and increasing pr oportion of <25 kDa proteins in epididymal spermatozoal membranes. PAG E patterns of detergent extracts indicate that 220 kDa, <25 kDa protei ns/glycoproteins are added onto the caput whereas 70 kDa are added ont o corpus spermatozoal membranes. The proportion of >170 kDa proteins e xtracted by proteases from cauda spermatozoal membranes was much highe r than extracted from testicular cell membranes. The reverse was the c ase with <25 kDa proteins. FPLC showed that the proportion of >170 kDa proteins with higher negative charge increases as spermatozoa undergo epididymal maturation. From the literature it appears that such >170 kDa proteins, extracted by SDS, CTAB and proteases are involved in cap acitation of spermatozoa, fusion of the membranes of the gametes, pene tration of ovum with spermatozoa, fertilization and division of the oo cytes.