Regiospecific H/D exchange

In a seminal contribution, Bock and co-workers conducted mechanistic studies on soluble as well as immobilised xylose isomerase from Streptomyces murinus sp. (Sweetzyme Q from NOVO) employing NMR-spectrometric methods. These studies confirmed the lack of deuterium exchange with solvent molecules of D-glucose and D-fructose regiospecifically C-deuterated at C-1 and C-2 [31]. It is noteworthy that they found the (IS)-diastereomer of D-(l- H)fruc-tose (29) was formed with perfect selectivity by isomerisation of D-(l- H)glu-cose (28) and so was the corresponding (IR)-epimer (31) when D-(2- H)glu-cose (30) was employed as the substrate (Scheme 6). 

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