Title : Human epididymis
protein-4 (
HE-4 ): a novel cross-class protease inhibitor
Abstract :
- Epididymal proteins represent the factors necessary for maturation of sperm and play a crucial role in sperm maturation
- HE-4 , an epididymal protein , is a member of whey acidic protein four-disulfide core ( WFDC ) family with no known function
- A WFDC protein has a conserved WFDC domain of 50 amino acids with eight conserved cystine residue
- HE-4 is a 124 amino acid long polypeptide with two WFDC domains
- 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
- Using SPR we have also observed that HE-4 shows a significant binding with all these proteases.
- Disulfide linkages are essential for this activity
- Moreover, HE-4 is N-glycosylated and highly stable on a wide range of pH and temperature
- Taken together this suggests that HE-4 is a cross-class protease inhibitor which might confer protection against microbial virulence factors of proteolytic nature