The hydrolytic and transferase action of alternanase on oligosaccharides.
Alternanase is an enzyme which endo-hydrolytically cleaves the alpha-(1-->3), alpha-(1-->6)-linked D-glucan, alternan. The main products are isomaltose, alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-D-Glc and the cyclic tetrasaccharide cyclo[-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->]. It is also capable of acting on oligosaccharide substrates. The cyclic tetrasaccharide is slowly hydrolyzed to isomaltose. Panose and the trisaccharide alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-D-Glc both undergo transglycosylation reactions to give rise to the cyclic tetrasaccharide plus D-glucose, with panose being converted at a much faster rate. The tetrasaccharide alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->4)-D-Glc is hydrolyzed to D-glucose plus the trisaccharide alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-D-Glc. Alternanase does not act on isomaltotriose, theanderose (6(Glc)-O-alpha-D-Glcp sucrose), or alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->4)-alpha-D-Glc. The enzyme releases 4-nitrophenol from 4-nitrophenyl alpha-isomaltoside, but not from 4-nitrophenyl alpha-D-glucopyranoside, 4-nitrophenyl alpha-isomaltotrioside, or 4-nitrophenyl alpha-isomaltotetraoside.
Côté
G L
GL
Fermentation Biochemistry Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, USDA, 1815 North University Street, Peoria, IL 61604, USA. cotegl@ncaur.usda.gov
Ahlgren
J A
JA
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005936:Glucans / Q000737:chemistry / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000378:metabolism*; D016695:Glycosyltransferases / Q000378:metabolism*; D006868:Hydrolysis; D007700:Kinetics; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry* / Q000378:metabolism*; D013379:Substrate Specificity; D014312:Trisaccharides / Q000737:chemistry / Q000378:metabolism
D005936:Glucans; D009844:Oligosaccharides; D014312:Trisaccharides; C008763:panose; D016695:Glycosyltransferases; D006026:Glycoside Hydrolases; C091143:alternanase