Purification and properties of NAD+-dependent sorbitol dehydrogenase from bacillu

Abstract

Sorbitol dehydrogenase (EC 1.1.1.14), which catalyzes the NAD+-linked interconversion of D-sorbitol and D-fructose, was purified and crystallized from cell-free extracts of Bacillus fructosus grown on D-sorbitol as a sole carbon source. The crystalline enzyme was homogeneous on disc electrophoresis and ultracentrifugation. The molecular weight was 102,000 by the sedimentation equilibrium method. The enzyme acted specifically on D-sorbitol, and showed an optimum pH at 9.0. The Kmvalues for D-sorbitol and NAD+were 1.1×10-2M and 2.2×10-4M, respectively. The enzyme activity was inhibited by p-chloromercuribenzoate, Ag+, Hg2+, and Cu2+. © 1999, Taylor & Francis Group, LLC. All rights reserved.