High Quality Content by WIKIPEDIA articles! APOBEC3G (apolipoprotein B mRNA-editing, enzyme-catalytic, polypeptide-like 3G) is a human enzyme encoded by the APOBEC3G gene that belongs to the APOBEC superfamily of proteins. This family of proteins has been suggested to play an important role in innate anti-viral immunity. APOBEC3G is a cytidine deaminase enzyme and is therefore known as DNA dC->dU-editing enzyme APOBEC-3G and APOBEC-related cytidine deaminase (ARCD).