Enantioselective glucosylation of (±)-secondary alcohols with plant glucosyltransferases
Two glucosyltransferases were isolated from plant cell cultures of Catharanthus roseus and Nicotiana tabacum. The enzyme from C. roseus enantioselectively glucosylated (±)-secondary alcohols to give the glucosides of (R)-alcohols, while the glucosylation with that from N. tabacum gave preferentially the glucosides of (S)-alcohols.
Shimoda, Kei,Kubota, Naoji,Hamada, Hiroki
p. 2319 - 2321
(2007/10/03)
Anomer-Selective Glucosylation of l-Menthol by Yeast α-Glucosidase
l-Menthol was glucosylated by the α-glucosidase (EC 3.2.1.20) of Saccharomyces cerevisiae using maltose as the glucosyl donor. When 50 mg of l-menthol and 1.6 M maltose in 10 mM citrate-phosphate buffer (pH 5.5) were incubated at 45°C, l-menthyl α-D-glucopyranoside (α-MenG) was α-anomer-selectively formed as a product. The specificity of the α-linkage was confirmed by 13C-NMR analysis. In the reaction mixture after 2 h, α-MenG was mainly accumulated in a crystalline form and the concentration of dissolved α-MenG was constant at 1.4 mM. The molar conversion yield of α-MenG produced based on the supplied l-menthol was maximally 30.7% at 48 h of reaction.
Anomer selective formation of l-menthyl α-D-glucopyranoside by α- glucosidase-catalyzed reaction
l-Menthol was glucosylated by the α-glucosidase (EC 3.2.1.20) of Saccharomyces cerevisiae using maltose as glucosyl donor. When 50 mg of l- menthol and 1 M maltose in 10 mM citrate-phosphate buffer (pH 7.0) were incubated for 24 h at 30°C, a menthylglucoside was selectively obtained as a product. The molar conversion yield based on supplied menthol was 4.5%. The product was identified as l-menthyl α-D-glucopyranoside (α-MenG) by 13C- NMR analysis.
Nakagawa,Yoshiyama,Shimura,Kirimura,Usami
p. 1914 - 1915
(2007/10/03)
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