IRON ION-CATALYZED OXIDATION OF TRYPTOPHAN - A SIMULATED BIOSYNTHETICROUTE TO ISATIN

Trptophan, its methyl ester and hemoglobin have been shown, separately , to produce isatin, among other products, by iron ion-catalyzed oxida tion with oxygen free radicals. Chemical and spectroscopic evidence of the oxidation products formed, in presence of mangiferin, indicate th at the reaction is effected by a number of discrete steps involving en capsulated oxoferryl radicals. CC-MS analysis of the silylated derivat ives of the superoxide radical-assisted (generated from asbestos fibre ) oxidation of hemoglobin has shown that kynurenine, a major systemic tryptophan metabolite, is absent. it is proposed that tryptophan in a bound form, e.g. in heme-proteins, is involved at least partly in the biosynthesis of isatin.