Carbohydrate Research 2005-02-28

Enzymatic synthesis of a 2-O-alpha-D-glucopyranosyl cyclic tetrasaccharide by kojibiose phosphorylase.

Hikaru Watanabe, Takanobu Higashiyama, Hajime Aga, Tomoyuki Nishimoto, Michio Kubota, Shigeharu Fukuda, Masashi Kurimoto, Yoshio Tsujisaka

Index: Carbohydr. Res. 340(3) , 449-54, (2005)

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Abstract

The glucosyl transfer reaction of kojibiose phosphorylase (KPase) from Thermoanaerobacter brockii ATCC35047 was examined using cyclo-{-->6)-alpha-d-Glcp-(1-->3)-alpha-d-Glcp-(1-->6)-alpha-d-Glcp-(1-->3)-alpha-d-Glcp-(1-->} (CTS) as an acceptor. KPase produced four transfer products, saccharides 1-4. The structure of a major product, saccharide 4, was 2-O-alpha-d-glucopyranosyl-CTS, cyclo-{-->6)-alpha-d-Glcp-(1-->3)-alpha-d-Glcp-(1-->6)-[alpha-d-Glcp-(1-->2)]-alpha-d-Glcp-(1-->3)-alpha-d-Glcp-(1-->}. The other transfer products, saccharides 1-3, were 2-O-alpha-kojibiosyl-, 2-O-alpha-kojitriosyl-, and 2-O-alpha-kojitetraosyl-CTS, respectively. These results showed that KPase transferred a glucose residue to the C-2 position at the ring glucose residue of CTS. This enzyme also catalyzed the chain-extending reaction of the side chain of 2-O-alpha-d-glycopyranosyl-CTS.