MOLECULAR-CLONING AND SEQUENCE-ANALYSIS OF THE CDNA-ENCODING PORCINE ACROSIN INHIBITOR

A full-length cDNA encoding the porcine acrosin inhibitor has been iso lated from a boar seminal vesicle cDNA library. Nucleotide sequence an alysis of the 667-bp cDNA predicts a precursor protein of 97 amino aci d residues, which includes a 26-residue signal peptide and a 71-residu e secreted protein. The predicted amino acid sequence of the mature pr otein agrees completely with that of the sperm-associated acrosin inhi bitor determined by conventional amino acid sequence analysis. However , the asparagine/aspartic acid and glutamine/glutamic acid substitutio ns, as reported in the seminal plasma counterpart, have not been obser ved. Southern blot analysis shows only a single hybridizing band with three different restriction endonucleases, suggesting the presence of a single copy of the acrosin inhibitor gene in the porcine genome.