Influence of Metal Ions and of Metal Chelates on the Hydrolysis of α-d-Glucose 1-Phosphate

Abstract

Abstract The hydrolysis reaction of α-d-glucose 1-phosphate has been studied in the presence of several metal ions and metal chelates at 40.0 and 60.0°C, in the pH range of 1.69–2.71, and at an ionic strength of 0.10 m (KNO3). The reaction rate was followed by the colorimetric method using a combination of the amidol reagent and 8.3% molybdate solution. Among the metal ions employed in this work, dipositive ions, such as manganese(II), cobalt(II), nickel(II), copper(II), zinc(II) and uranyl ions, were observed to be nearly without effect on the rate of hydrolysis, while iron(III) and thorium(IV) ions demonstrated a negative catalytic effect. On the other hand, all the chelating agents employed tend to restore the reaction rate in reference to the corresponding metal-ion-effected reactions. With the 1:1 thorium(IV)-EDTA and the 1:1 iron(III)-EDTA chelate system, the rate was completely restored. Both iron(III)-kojate and thorium(IV)-Tiron chelate systems restored the reaction rate to a lesser extent. The roles of the chelating agents were discussed. The reaction mechanism in the presence of the catalyst species has been considered, and two possible mechanisms have been put forward for the present reactions.