Each vial contains 200 g of lyophilized peptide consisting of human hepsin amino acids 241-260 (GGYLPFRDPNSEENSNDIAL). This peptide can be used in conjunction with Caymans hepsin polyclonal antibody - affinity-purified (aa 2416-260) (Item No. 100022) to block protein-antibody complex formation during analysis for hepsin. Hepsin is a type II membrane-associated protein that has a extracellular proteolytic domain and exhibits low sequence homology to other known proteases.1,2 Recently, hepsin overexpression was observed in prostate, breast, kidney, and ovarian cancers and due to low homology to other known proteases may provide a unique target for pharmacological therapy.3,4,5,6,7 Hepsin is necessary for cell growth in vitro8 and may play a role in metastatic expansion by factor VII activation.9,6 The observed molecular mass of hepsin by immunoblotting is 45.3 kDa. Cloning and characterization of murine and rat hepsin indicate 88% overall homology with human hepsin.10,11,12 Northern blotting reveals high levels of hepsin transcripts in liver.2,7