H. Nakagawa et al., ANOMER-SELECTIVE GLUCOSYLATION OF L-MENTHOL BY YEAST ALPHA-GLUCOSIDASE, Bioscience, biotechnology, and biochemistry, 62(7), 1998, pp. 1332-1336
l-Menthol was glucosylated by the alpha-glucosidase (EC 3.2.1.20) of S
accharomyces cerevisiae using maltose as the glucosyl donor. When 50 m
g of l-menthol and 1.6 M maltose in 10 mM citrate-phosphate buffer (pH
5.5) were incubated at 45 degrees C, l-menthyl alpha-D-glucopyranosid
e (alpha-MenG) was alpha-anomer-selectively formed as a product. The s
pecificity of the alpha-linkage was confirmed by C-13-NMR analysis. In
the reaction mixture after 2 h, alpha-MenG was mainly accumulated in
a crystalline form and the concentration of dissolved alpha-MenG was c
onstant at 1.4 mM. The molar conversion yield of alpha-MenG produced b
ased on the supplied l-menthol was maximally 30.7% at 48 h of reaction
.