The NS3/4A serine protease is one of the hepatitis C virus proteases involved in the viral replication that catalyzes the cleavage of HCV polyprotein precursor encoded by HCV genome into fully functional virion. A mature HCV virion consists of at least ten individual proteins, including four structural proteins (C, E1, E2 and p7) and six nonstructural (NS) proteins (NS2, NS3, NS4A, NS4B, NS5A and NS5B). The NS3/4A serine protease is a non-covalent heterodimer complex characterized by two domains, including the N-terminal serine protease domain of NS3 (catalytic subunit) and the NS4A cofactor (activation subunit) that cleaves the HCV polyprotein precursor at four junctions, including NS3/NS4A, NS4A/NS4B, NS4B/NS5A and NS5A/NS5B.