The mammalian zona pellucida is composed of four major glycoproteins, ZP1, ZP2, ZP3 and ZP4, which may act as sperm receptors. Two forms of porcine ZP4 peptides exist: one consisting of 128 amino acid residues and the other of 133 amino acid residues. These two peptides are identical, except the larger form contains an additional five amino acid sequence at its carboxy-terminal end. Both peptides have two potential N-linked glycosylation sites. The smaller peptide shares 39.1% identity with the amino-terminal region of mouse ZP2 polypeptide. Based on results from animal studies, ZP4 antigen is a promising candidate for the development of a contraceptive vaccine.
Processed zona pellucida sperm-binding protein 4; zona pellucida 4; zona pellucida B glycoprotein; Zona pellucida glycoprotein 4; Zona pellucida protein B; Zona pellucida sperm-binding protein 4; Zp-4