The total number of mammalian cortical granule proteins has been estimated to be between four and fourteen or more [10,19,20]. Several specific proteins have been iden- tified as cortical granule proteins [21]. N-acetylglucosami- nidase was detected in exudates of ionophore-activated mouse oocytes using an enzymatic assay and was local- ized in the cortical granules at the electron microscopic level [13]. Approximately 90% of oocyte N-acetylglu- cosaminidase was released following in vivo fertilization and was shown using competitive inhibitors or anti-N- acetylglucosaminidase antibodies to be responsible for the zona block to polyspermy [13]. Ovoperoxidase was detected in the cortical granules of unfertilized mouse oocytes at the ultrastructural level using the '-diami- nobenzidine (DAB).
