DNA dC->dU-editing enzyme APOBEC-3C is a protein that in humans is encoded by the APOBEC3C gene. A3C belong to the A3 family of cytidine deaminases that act as restriction factors against diverse retroviruses. A3C was reported to inhibit simian immunodeficiency deficiency virus potently rather than HIV-1, in absence of viral infectivity factor, Vif. Enhancing A3C's catalytic activity had only a marginal effect on HIV-1 replication (in absence of Vif), the counteractive viral mechanism is unclear. A3C was also shown to inhibit other viruses.