Purification and characterization of a sperm motility inhibiting factor from caprine epididymal plasma.
Several studies have been reported on the occurrence of sperm motility inhibiting factors in the male reproductive fluids of different mammalian species, but these proteins have not been adequately purified and characterized. A novel sperm motility inhibiting factor (MIF-II) has been purified from caprine epididymal plasma (EP) by Hydroxylapatite gel adsorption chromatography, DEAE-Cellulose ion-exchange chromatography and chromatofocusing. The MIF-II has been purified to apparent homogeneity and the molecular weight estimated by Sephacryl S-300 gel filtration is 160 kDa. MIF-II is a dimeric protein, made up of two subunits each having a molecular mass of 80 kDa as shown by SDS-PAGE. The isoelectric point of MIF-II is 5.1 as determined by chromatofocusing and isoelectric focusing. It is a heat labile protein and maximal active at the pH 6.9 to 7.5. The sperm motility inhibiting protein factor at 2 microg/ml (12.5 nM) level showed maximal motility-inhibiting activity. The observation that the epididymal plasma factor lowered the intracellular cAMP level of spermatozoa in a concentration-dependent manner suggests that it may block the motility of caprine cauda spermatozoa by interfering the cAMP dependent motility function. The results revealed that the purified protein factor has the potential of sperm motility inhibition and may serve as a vaginal contraceptive. The antibody raised against the MIF-II has the potential for enhancement of forward motility of cauda-spermatozoa. This antibody may thus be useful for solving some of the problems of male infertility due to low sperm motility.
Das
Sujoy
S
Indian Institute of Chemical Biology, Kolkata, India.
Saha
Sudipta
S
Majumder
Gopal Chandra
GC
Dungdung
Sandhya Rekha
SR
D000818:Animals; D005591:Chemical Fractionation / Q000379:methods*; D000242:Cyclic AMP / Q000378:metabolism; D004822:Epididymis / Q000737:chemistry*; D006041:Goats; D006801:Humans; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D008297:Male; D055101:Semen Analysis; D013053:Spectrophotometry; D013081:Sperm Motility / Q000187:drug effects*; D013094:Spermatozoa / Q000166:cytology / Q000187:drug effects
D000242:Cyclic AMP