Mechanism of the Reaction between Cobalamin(II) and Periodate

Abstract

The reaction between a reduced form of cobalamin (cobalamin(II), Cbl(II)) and periodate in alkaline medium is studied. It is shown that there is no destruction of cobalamin at the ratio of [Cbl(II)] : [IO\(_{4}^{ - }\)] = 2 : 1. The reaction mechanism includes interactions between Cbl(II) and H₄IO\(_{6}^{ - }\) and H₃IO\(_{6}^{{2 - }}\) leading to the formation of aquacobalamin and radicals I(VI), which rapidly oxidize the second molecule of Cbl(II) to aquacobalamin.