title: A novel metabolic pathway for glucose production mediated by α-glucosidase-catalyzed conversion of 1,5-anhydrofructose.
abstract: α-Glucosidase is in the glycoside hydrolase family 13 (13AG) and 31 (31AG). Only 31AGs can hydrate the D-glucal double bond to form α-2-deoxyglucose. Because 1,5-anhydrofructose (AF), having a 2-OH group, mimics the oxocarbenium ion transition state, AF may be a substrate for α-glucosidases. α-Glucosidase-catalyzed hydration produced α-glucose from AF, which plateaued with time. Combined reaction with α-1,4-glucan lyase and 13AG eliminated the plateau. Aspergillus niger α-glucosidase (31AG), which is stable in organic solvent, produced ethyl α-glucoside from AF in 80% ethanol. The findings indicate that α-glucosidases catalyze trans-addition. This is the first report of α-glucosidase-associated glucose formation from AF, possibly contributing to the salvage pathway of unutilized AF.
authors.affiliation: Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan.
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Kim
authors.forename: Wataru
authors.initials: W
authors.lastname: Saburi
authors.forename: Shukun
authors.initials: S
authors.lastname: Yu
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakai
authors.forename: Janjira
authors.initials: J
authors.lastname: Maneesan
authors.forename: Min-Sun
authors.initials: MS
authors.lastname: Kang
authors.forename: Seiya
authors.initials: S
authors.lastname: Chiba
authors.forename: Doman
authors.initials: D
authors.lastname: Kim
authors.forename: Masayuki
authors.initials: M
authors.lastname: Okuyama
authors.forename: Haruhide
authors.initials: H
authors.lastname: Mori
authors.forename: Atsuo
authors.initials: A
authors.lastname: Kimura
mesh_terms: D000818:Animals; D001234:Aspergillus niger / Q000201:enzymology; D001516:Bees / Q000201:enzymology; D002384:Catalysis; D004789:Enzyme Activation / Q000502:physiology; D000431:Ethanol / Q000737:chemistry; D019612:Fagopyrum / Q000201:enzymology; D005632:Fructose / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D005947:Glucose / Q000096:biosynthesis* / Q000378:metabolism; D000461:Rhodophyta / Q000201:enzymology; D012997:Solvents / Q000737:chemistry; D013213:Starch / Q000378:metabolism; D013295:Streptococcus mutans / Q000201:enzymology; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D014867:Water / Q000737:chemistry; D000520:alpha-Glucosidases / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D012997:Solvents; D014867:Water; D005632:Fructose; D000431:Ethanol; C048927:1,5-anhydrofructose; D013213:Starch; D000520:alpha-Glucosidases; D005947:Glucose