Possible role of vanadium in biological oxidations. The oxidation of uracil by hydrogen peroxide in acidic aqueous solution

A possible role in biological oxidations of vanadium, whose presence in mammals, including the human beings, has been recently discovered, was examined by comparing its catalytic behaviour with that of iron in the oxidation of uracil by hydrogen peroxide in water. Other metal ions were also investigated. The reactions were run at 37 degrees C in acidic (pH-1.5) aqueous solutions thus mimicking the conditions met under acute tissue inflammation. The time of disappearance of hydrogen peroxide, added in excess, and the conversion of uracil were measured. The products of the reaction are dioxygen, 5,6-cis-dihydroxy-5,6-dihydrouracil, 5,6-trans-dihydroxy-5,6-dihydrouracil, 1-formyl-5-hydroxyhydantoin and 6-hydroxyisobarbituric acid. The dioxygen evolved was quantitatively determined in all runs. The quantitative measurements of the products of uracil oxidation have been carried out in some selected experiments. The results indicate that, among the various metal ions examined, together with iron and copper, only vanadium exhibits a catalytic effect in the oxidation of uracil.