A search has been initiated for lead inhibitors of the non-structural protein 3 (NS3)-associated NTPase/helicase activities of hepatitis C virus,the related West Nile virus, Japanese encephalitis virus and the human mitochondrial Suv3 enzyme. Random screening of a broad range of unre-lated low-molecular mass compounds,employing both RNA and DNA substrates, revealed that 4,5,6,7-tetra-bromobenzotriazole (TBBT) hitherto known as a potent highly selective inhibitor of protein kinase 2,is a good inhibitor of the helicase,but not NTPase,activity of hepa-titis C virus NTPase/helicase. .
