title: Synthesis of highly branched anionic α-glucans by thermostable phosphorylase-catalyzed α-glucuronylation.
abstract: Highly branched anionic α-glucans were enzymatically synthesized by thermostable phosphorylase-catalyzed α-glucuronylation of highly branched cyclic dextrin using α-D-glucuronic acid 1-phosphate (GlcA-1-P) as a glycosyl donor. The resulting products were characterized by ¹H NMR measurement as well as high performance anion exchange chromatographic and MALDI-TOF MS analyses after treatments with several amylases. α-D-Glucose 1-phosphate was detected in the reaction mixtures, suggesting the occurrence of phosphorolysis in the α-glucuronylation. The glucuronylation ratios of glucuronic acid residues to non-reducing ends were evaluated from quantification of α-D-glucose 1-phosphate and inorganic phosphate in the reaction mixtures, which were relatively in good agreement with those determined by ¹H NMR analysis of the products. The glucuronylation ratios increased with increasing feed ratios of GlcA-1-P/non-reducing ends.
authors.affiliation: Department of Chemistry, Biotechnology, and Chemical Engineering, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Takemoto
authors.forename: Hironori
authors.initials: H
authors.lastname: Izawa
authors.forename: Yuta
authors.initials: Y
authors.lastname: Umegatani
authors.forename: Kazuya
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Akiko
authors.initials: A
authors.lastname: Kubo
authors.forename: Michiyo
authors.initials: M
authors.lastname: Yanase
authors.forename: Takeshi
authors.initials: T
authors.lastname: Takaha
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Kadokawa
mesh_terms: D000838:Anions / Q000737:chemistry / Q000378:metabolism; D055162:Biocatalysis; D004795:Enzyme Stability; D006031:Glycosylation; D009844:Oligosaccharides / Q000096:biosynthesis* / Q000737:chemistry*; D006005:Phosphorylases / Q000737:chemistry* / Q000378:metabolism*; D013696:Temperature
chemical_list: D000838:Anions; D009844:Oligosaccharides; D006005:Phosphorylases