O6-Benzylguanine

O-Benzylguanine (O6-BG) is a synthetic derivative of guanine. It is an antineoplastic agent. It exerts its effect by acting as an inhibitor of the enzyme O6-alkylguanine-DNA alkyltransferase which leads to interruption of DNA repair and increases the potency of other chemotherapeutic agents that damage DNA, such as temozolomide.