KINETIC STUDY OF A Zn2 + -CATALYZED TRANSAMINATION REACTION BETWEEN PYRIDOXAMINE ANALOGS WITH A PYRIDINOPHANE STRUCTURE AND alpha -KETO ACIDS.

Article abstract of DOI:10.1246/bcsj.56.2263

The kinetics of the nonenzymatic transamination reaction from pyridoxamine analogs with a pyridinophane structure to a-keto acids catalyzed by Zn**2** plus were investigated by monitoring the changes in the absorption spectra in methanol. It was found that these reactions obeyed first-order kinetics for the formation of the Zn**2** plus chelate of an aldimine. No appreciable change in the reaction rate was observed when the concentration of the a-keto acid was increased, indicating that the isomerization of the ketimine chelate to the aldimine chelate is the rate-determining step. There was a considerable enhancement of the reaction rate when the molar ratio of the zinc ion to the pyridoxamine analogs was reduced from 1/1 to 0. 5/1.