Complete amino acid sequence of human seminal plasma β‐inhibin

Abstract
The complete sequence of a 94 amino acid human seminal plasma polypeptide exhibiting inhibin‐like activity is presented. This molecule, called β‐inhibin, selectively and specifically suppresses the release of pituitary FSH in vivo as well as in vitro. It does not affect the secretion of LH. Such a novel acidic protein contains a very basic C‐terminal segment which is easily cleaved by mild tryptic digestion. It is predicted that the FSH inhibiting activity may reside within this region of the molecule. This would imply a post Gin‐Arg cleavage to release the basic C‐terminal active moiety.