Determination of carbonyl acids formed upon periodate oxidation II. Analysis of various carbonyl acid precursors

Abstract

An analysis has been made of the time course for appearance of carbonyl acids from certain compounds as a function of incubation time in acid periodate. Sugar acids, phosphorylated sugar acids, glycerate, tartronic semialdehyde, and tartrate yield theoretical quantities of glyoxylate upon periodate oxidation by the particular procedure employed. Reduction with sodium borohydride prior to periodate oxidation of 2-ketogluconate, hydroxypyruvate and α-acetolactate makes possible the quantitative determination of these compounds in the presence of large excesses of carbonyl acids. The production of glyoxylate from ketoses has been studied. Disaccharides containing 1,4-linked hexoses are oxidized to one mole of glyoxylate per mole of sugar. Two moles of glyoxylate are obtained per mole of aldobionic acid oxidized. Periodate oxidation of sugar acid lactones has been shown to result in small excesses of glyoxylate formed as a result of an “overoxidation” reaction of periodate. The production of small amounts of glyoxylate during the periodate oxidation of hexoses has been studied. Reduction with sodium borohydride prior to periodate oxidation greatly reduces the glyoxylate yield from sugars. The periodate oxidation of ascorbic acid has been shown to yield an almost theoretical quantity of glyoxylate. Some applications of the assay procedure to biological systems have been discussed.