| 摘要 |
PROBLEM TO BE SOLVED: To obtain a sorbitol dehydrogenase excellent in substrate affinity and substrate specificity, to obtain microorganisms capable of producing the enzyme, and to provide a method for producing the enzyme. SOLUTION: This sorbitol dehydrogenase has the physicochemical properties as follows: (1) action: dehydrogenically oxidizing D-sorbitol in the presence of NAD+ to form D-fructose; by the reaction reverse to the above, reducing D-fructose in the presence of NADH to form D-sorbitol and NAD+; (2) substrate specificity: when the Vmax/Km for D-sorbitol is assumed to be 100, the Vmax/Km for galactitol is about <=37, being about <=3 for L-iditol, and inert to D- arabitol, D-mannitol, xylitol and D-glucose; and (3) the Km for sorbitol is <=5.9 mM.
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