著者

Feunai Agape Papalii Tautau Minoru Izumi Emiko Matsunaga Yujiro Higuchi Kaoru Takegawa

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

vol.67, no.3, pp.87-93, 2020-09-03 (Released:2020-09-03)

参考文献数

36

被引用文献数

2

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α-L-Rhamnosidases (α-L-Rha-ases, EC 3.2.1.40) are glycosyl hydrolases (GHs) that hydrolyze a terminal α-linked L-rhamnose residue from a wide spectrum of substrates such as heteropolysaccharides, glycosylated proteins, and natural flavonoids. As a result, they are considered catalysts of interest for various biotechnological applications. α-L-rhamnose (6-deoxy-L-mannose) is structurally similar to the rare sugar α-L-mannose. Here we have examined whether microbial α-L-Rha-ases possess α-L-mannosidase activity by synthesizing the substrate 4-nitrophenyl α-L-mannopyranoside. Four α-L-Rha-ases from GH78 and GH106 families were expressed and purified from Escherichia coli cells. All four enzymes exhibited both α-L-rhamnosyl-hydrolyzing activity and weak α-L-mannosyl-hydrolyzing activity. SpRhaM, a GH106 family α-L-Rha-ase from Sphingomonas paucimobilis FP2001, was found to have relatively higher α-L-mannosidase activity as compared with three GH78 α-L-Rha-ases. The α-L-mannosidase activity of SpRhaM showed pH dependence, with highest activity observed at pH 7.0. In summary, we have shown that α-L-Rha-ases also have α-L-mannosidase activity. Our findings will be useful in the identification and structural determination of α-L-mannose-containing polysaccharides from natural sources for use in the pharmaceutical and food industries.

著者

Minoru Izumi Koichi Fukase

出版者

(社)日本化学会

雑誌

Chemistry Letters (ISSN:03667022)

巻号頁・発行日

vol.34, no.4, pp.594-595, 2005 (Released:2005-03-19)

参考文献数

18

被引用文献数

19

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New reductive benzylation of hydroxy functions was effected by using the combination of benzaldehyde, TMSCl, and Et3SiH. TMSCl first reacts with alcohols to form HCl, which is probably the ultimate catalyst for this reaction system. TMSCl can also trap water and thus effectively promote dehydration reactions when more than stoichiometric amount of TMSCl is used. Although excess TMSCl was required for the foregoing reactions, TMSCl could be readily removed by simple evaporation.