CHARACTERIZATION OF THE ZONA-PELLUCIDA GLYCOPROTEINS FROM BOVINE OVARIAN AND FERTILIZED-EGGS

Bovine zona pellucida (ZP) glycoproteins from ovarian egg emerged as t hree bands with molecular mass of 78 kDa, 64 kDa and 21 kDa in SDS-PAG E under reducing conditions. Endo-beta-galactosidase (E beta G) digest ion of the glycoproteins yielded five products with molecular mass of 76 kDa (E beta G-76), 68 kDa (E beta G-68), 63 kDa (E beta G-63), 47 k Da (E beta G-47) and 21 kDa (E beta G-21) under the same conditions. T he N-terminal amino acid sequences of E beta G-76 and E beta G-21 were identical. This fact together with the results of diagonal SDS-PAGE i ndicated that E beta G-21 (N-terminal region) is linked to E beta G-63 (C-terminal region) through disulfide bond to form E beta G-76. Immun oblot analysis using anti-pig ZP protein antibodies revealed that bovi ne E beta G-76, E beta G-68 and E beta G-47 correspond to pig PZP5 PZP 3 alpha and PZP3 beta glycoproteins, respectively. The E beta G-76 and E beta G-68 components were shown to be specifically cleaved during f ertilization.