Cytochrome P450BM-3 reduces aldehydes to alcohols through a direct hydride transfer

► Cytochrome P450BM-3 reduced aldehydes to alcohols efficiently (kcat ∼ 25 min−1). ► Reduction is a direct hydride transfer from R-NADP2H to the carbonyl moiety. ► P450 domain variants enhance reduction through potential allosteric/redox interactions. ► Novel reaction will have implications for metabolism of xenobiotics.