Mechanism-Based Inhibition of Human Steroid 5α-Reductase by Finasteride: Enzyme-Catalyzed Formation of NADP–Dihydrofinasteride, a Potent Bisubstrate Analog Inhibitor by Herbert G. Bull and others (1996, 10.1021/ja953069t)

Journal of the American Chemical Society 118, 2359–2365. Radiolabel recovery, denaturation, purification and spectroscopy establish the cofactor adduct. Figure 7 compares enolate protonation with cofactor trapping. Slow dissociation/breakdown motivates a timescale-qualified description of inhibition.