FIGURE 5.

Postulated reaction mechanism of GatDH for the oxidation of 1,2-(S)-pentanediol according to Filling et al. (41). A charge relay system is formed by a hydrogen bond network involving Tyr¹⁵¹-OH, the 2′-OH group of the nicotinamide connected ribose moiety, Lys¹⁶³-NH₃⁺, Asn¹¹⁶-Oδ1, Asn¹¹⁶-O, and a well conserved water molecule, Wat²⁰⁷³. Catalysis is initiated by proton transfer from the secondary hydroxyl-group of the substrate onto Tyr¹⁵¹-OH followed by a hydride transfer to the nicotinamide ring C4 atom. The proton from the secondary hydroxyl group is transmitted to the solvent via the hydrogen network.