Glucose isomerase catalysed isomerisation reactions of (2R,3R)-configured aldofuranoses into the corresponding open-chain 2-ketoses

Immobilised glucose isomerase (EC 5.3.1.5) accepted various (2R,3R)-configured aldofuranoses such as d-erythrose, as well as homologous C-5-modified d-ribose derivatives, as substrates. In the case of d-crythrose, quantitative conversion into d-glycero-tetrulose took place. d-Ribofuranoses were converted into the corresponding open-chain 2-ketoses in isolated yields of 65%. Surprisingly, l-crythrose also turned out to be a substrate of this enzyme.