The interaction of divicine with glutathione and pyridine nucleotides.

Native divicine , a pyrimidine aglycone strongly implicated in the pathogenesis of favism, undergoes rapid auto-oxidation according to a 1:1 stoichiometry with respect to the oxygen disappeared. In the presence of oxygen divicine re-oxidizes both NADPH and NADH, whereby a red-ox cycling is perpetuated between hydroquinonic and quinonic species of divicine itself. The oxygen-dependent interaction of divicine with GSH involves a 90% oxidation to GSSG and the parallel formation of two distinct adducts. Both adducts have been isolated by means of HPLC and characterized in their spectral properties. The one having maximum absorption at 305 nm is susceptible of reduction by glutathione reductase, while the adduct with maximum absorption at 320 nm is stable and is likely to represent a dead-end complex of divicine .