OAS1 is an enzyme included in the 2’,5’-oligoadenylate synthase family. This enzyme is induced by interferons and uses adenosine triphosphate in 2’-specific nucleotidyl transfer reactions to synthesize 2’,5’-oligoadenylates(2-5As). These molecules activate latent RNase L, which results in viral RNA degradation and the inhibition of viral replication. OAS1 may play a role in mediating resistance to virus infection, control of cell growth, differentiation, and apoptosis. Recombinant OAS1 protein , expressed in E. coli and purified by using conventional chromatography techniques.