De novo-designed artificial Cu protein (ArCuP), 3SCC, featuring a trigonal Cu(His)3 binding environment, has been shown to activate H2O2, O2, and benzylic C-H bonds of abiotic substrates. We outline the mechanism of ArCuP-catalyzed C-H peroxidation of one such abiotic substrate, the peroxidation of benzyl alcohol to benzaldehyde.