ns2-3 protease (of hepatitis c virus, hcv) is an enzyme responsible for proteolytic cleavage between ns2 and ns3, which are non-structural proteins that form part of the hcv virus particle. ns3 protease of hepatitis c virus, on the other hand, is responsible for the cleavage of non-structural protein downstream. both of these proteases are directly involved in hcv genome replication, that is, during the viral life-cycle that leads to virus multiplication in the host that has been infected by the virus.