[1] The purpose of this reaction is to reoxidize glycolytically formed NADH to NAD+, replenishing this important reductant used in glycolysis and allowing for the continued production of ATP in the absence of oxygen.
[3][4] OcDH is a monomer with a molecular weight of 38kD[5] made of two functionally distinct subunits.
[7] Isothermal titration calorimetry (ITR),[3] nuclear magnetic resonance (NMR)[8] crystallography,[6][8] and clonal studies[1][6] of OcDH and its substrates have led to the identification of the enzyme reaction mechanism.
The juxtaposition of these groups on the substrates results in the formation of a Schiff base which is subsequently reduced to D-octopine.
Upon binding to NADH, amino acid residues lining either side of the active site within the space between the domains of OcDH act as a “molecular ruler”, physically limiting the size of the substrates that can fit into the active site.