In this paper we present computational studies directed at elucidating the mechanism of the oxidation of benzyl alcohol by liver alcohol dehydrogenase (LADH). This enzyme reaction involves a hydride transfer from the alcohol substrate to the nicotinamide adenine dinucleotide coenzyme and a proton relay that deprotonates the alcohol substrate. Electronic structure calculations at various levels of theory were performed on a 148-atom model of the active site, and classical molecular dynamics simulations were performed on the entire solvated LADH dimer. These calculations support the hypothesis that alcohol deprotonation occurs prior to the hydride transfer step and that the alcohol deprotonation facilitates the hydride transfer by lowering the barrier for hydride transfer. In this postulated mechanism, the alcohol deprotonation leads to a zinc-bound alkoxide ion, and the subsequent hydride transfer leads to the benzaldehyde product. The calculations indicate that the zinc-bound alkoxide forms a strong hydro...