Reactivity of some sugars and sugar phosphates towards gold(III) in sodium acetate–acetic acid buffer medium

• Published in: Carbohydrate research 2001-01, Vol.330 (1), p.115-123
• Main Authors: Sen Gupta, Kalyan Kali, Pal, Biswajit, Begum, Bilkis Ara
• Format: Article
• Language: English
• Subjects: Aldehydes - metabolism; Antirheumatic Agents - metabolism; Buffers; Carbohydrate Metabolism; Chlorides - pharmacology; Free Radicals - metabolism; Gold - metabolism; Gold(III); Hydrogen-Ion Concentration; Kinetics; Monosaccharides - metabolism; Oxidants - metabolism; Oxidation-Reduction; Sodium Acetate; Sodium acetate–acetic acid; Sugar Phosphates - metabolism; Sugars and sugar phosphates; Thermodynamics
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/S0008-6215(00)00181-6

The kinetics of the oxidation of some aldoses and aldose phosphates have been studied spectrophotometrically in sodium acetate–acetic acid buffer medium at different temperatures. The reactions are first order with respect to [Au(III)] and [substrate]. Both H + and Cl − ions retard the reaction. The reactions appear to involve different gold(III) species, viz. AuCl 4 −, AuCl 3(OH 2) and AuCl 3(OH) −. The results are interpreted in terms of the probable intermediate formation of free radicals and Au(II). Aldoses react with gold(III) in the order: triose>tetrose>pentose>hexose. The sugar phosphates react with gold(III) at a faster rate than the parent sugars except glucose-1-phosphate, which reacts at slower rates than glucose. A tentative reaction mechanism leading to the formation of products has been suggested.