PMID: 23139753

 

    Legend: Sugar

Title : Human epididymis protein-4 ( HE-4 ): a novel cross-class protease inhibitor

Abstract :
  1. Epididymal proteins represent the factors necessary for maturation of sperm and play a crucial role in sperm maturation
  2. HE-4 , an epididymal protein , is a member of whey acidic protein four-disulfide core ( WFDC ) family with no known function
  3. A WFDC protein has a conserved WFDC domain of 50 amino acids with eight conserved cystine residue
  4. HE-4 is a 124 amino acid long polypeptide with two WFDC domains
  5. Here, we show that HE-4 is secreted in the human seminal fluid as a disulfide-bonded homo-trimer and is a cross-class protease inhibitor inhibits some of the serine , aspartyl and cysteine proteases tested using hemoglobin as a substrate
  6. Using SPR we have also observed that HE-4 shows a significant binding with all these proteases.
  7. Disulfide linkages are essential for this activity
  8. Moreover, HE-4 is N-glycosylated and highly stable on a wide range of pH and temperature
  9. Taken together this suggests that HE-4 is a cross-class protease inhibitor which might confer protection against microbial virulence factors of proteolytic nature