Eppin: an effective target for male contraception

Mol Cell Endocrinol. 2006 May 16;250(1-2):157-62. doi: 10.1016/j.mce.2005.12.039. Epub 2006 Jan 19.


Eppin (epididymal protease inhibitor) is a member of the whey acidic protein (WAP)-type four-disulfide core (WFDC) gene family. This study provides updated information on Eppin and the Eppin-like genes within the Eppin cluster on human chromosome 20. A virtual structural model of the Eppin protein demonstrates that the C-terminal half of Eppin is structurally homologous to the Kunitz-type trypsin inhibitor. The Eppin N-terminal may have structural similarities to defensin-type molecules, rather than to that of the WAP consensus sequence. Human spermatozoa have a receptor for Eppin. When recombinant semenogelin (Sg) is digested with PSA many low molecular weight fragments are produced. However, when Eppin is bound to Sg, digestion by PSA is modulated. Addition of antibodies to the C-terminal of Eppin resulted in blocking PSA activity modulation. We can hypothesize from our analysis of anti-Eppin epitopes on Eppin that when anti-Eppin antibodies are bound to Eppin on the sperm surface they block the binding site for semenogelin.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing
  • Antibodies / pharmacology
  • Chromosomes, Human, Pair 20 / genetics
  • Contraception*
  • Epitopes / immunology
  • Fertility / genetics
  • Humans
  • Male
  • Multigene Family
  • Proteinase Inhibitory Proteins, Secretory
  • Proteins / antagonists & inhibitors*
  • Proteins / genetics
  • Proteins / metabolism*
  • Seminal Vesicle Secretory Proteins / metabolism
  • Spermatozoa / cytology
  • Spermatozoa / metabolism*


  • Antibodies
  • Epitopes
  • Eppin protein, human
  • Proteinase Inhibitory Proteins, Secretory
  • Proteins
  • Seminal Vesicle Secretory Proteins
  • seminal vesicle-specific antigen