title: Enzymatic synthesis of glycosyl cyclic tetrasaccharide with 6-alpha-glucosyltransferase and 3-alpha-isomaltosyltransferase.
abstract: Transglycosylation reactions to cyclic tetrasaccharide (CTS, cyclo[-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->]) and its derivatives were investigated. An enzyme, 6-alpha-glucosyltransferase, which is involved in CTS synthesis from starch, from Bacillus globisporus C11 produced 4-O-alpha-glucosyl-CTS (4G-CTS) from a mixture containing CTS and maltopentaose. Another enzyme, 3-alpha-isomaltosyltransferase, synthesized 3-O-alpha-isomaltosyl-CTS (3IM-CTS) from CTS and panose. Two novel branched CTSs, 3-O-alpha-isomaltosyl-4-O-alpha-glucosyl-CTS (3IM-4G-CTS) and 3-O-alpha-isomaltosyl-(4-O-alpha-glucosyl)-CTS [3IM-(4G)-CTS], were synthesized by the isomaltosyl transfer of IMT into 4G-CTS. IMT also produced a novel saccharide, 3-O-alpha-isomaltosyl-3-O-alpha-isomaltosyl-CTS (3IM-3IM-CTS) from 3IM-CTS. It was confirmed that the oligosaccharides, including 4G-CTS, 3IM-CTS, 3IM-4G-CTS, 3IM-(4G)-CTS and 3IM-3IM-CTS, remaining in the reaction mixture during the production of CTS from starch were the transfer products of 6GT and IMT into CTS.
authors.affiliation: Amase Institute, Hayashibara Biochemical Laboratories, Inc., 7-7 Amase-minami-machi, Okayama 700-0834, Japan. amaseken@hayashibara.co.jp
authors.forename: Hajime
authors.initials: H
authors.lastname: Aga
authors.forename: Takanobu
authors.initials: T
authors.lastname: Higashiyama
authors.forename: Hikaru
authors.initials: H
authors.lastname: Watanabe
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Sonoda
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Yuen
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Nishimoto
authors.forename: Michio
authors.initials: M
authors.lastname: Kubota
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Fukuda
authors.forename: Masashi
authors.initials: M
authors.lastname: Kurimoto
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Tsujisaka