Although there is a recognizable Rossmann-type fold, the coenzyme-binding region of ALDH2 binds NAD+ in a manner not seen in other NAD+-binding enzymes. The positions of the residues near the nicotinamide ring of NAD+ suggest a chemical mechanism whereby Glu268 functions as a general base through a bound water molecule. The sidechain amide nitrogen of Asn169 and the peptide nitrogen of Cys302 are in position to stabilize the oxyanion present in the tetrahedral transition state prior to hydride transfer. The functional importance of residue Glu487 now appears to be due to indirect interactions of this residue with the substrate-binding site via Arg264 and Arg475.

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Recently we reported on a period doubling route to chaos in the peroxidase-oxidase (PO) reaction. This was the first report of a universal route to chaos in the PO reaction. Here we present further evidence of universality in the transition to chaos in the PO reaction. We have observed period three oscillations under conditions near where chaotic oscillations are found, and we have found that chaotic oscillations in this reaction contain unstable periodic orbits. We also report numerical results from a simple model of the PO reaction. These theoretical calculations qualitatively reproduce the spectrum of behaviors observed in this reaction.

Quasiperiodicity in a detailed model of the peroxidase-oxidase reaction Multiple time scale analysis of two models for the peroxidase-oxidase reaction Chaos 5, 448 (1995); 10.1063/1.166116 Dynamic elements of mixedmode oscillations and chaos in a peroxidase-oxidase model network J. Chem. Phys. 90, 4168 (1989); 10.1063/1.455774 Bistability in chemical reaction networks: Theory and application to the peroxidase-oxidase reaction

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