Action of transglucosidase from Aspergillus niger on maltoheptaose and [U-(13)C]maltose.
Oligosaccharides synthesized from a mixture of maltoheptaose and [U-(13)C]maltose with transglucosidase [EC 2.4.1.24] from Aspergillus niger were investigated. When the reaction mixture was incubated at 15 degrees C for 1h, several types of oligosaccharides with DP (degree of polymerization) 2 to DP8 containing alpha-D-Glcp-(1-->6)-maltoheptaose were detected by liquid chromatography-mass spectrometry (LC-MS) and methylation analysis. Most of these compounds consisted of alpha-(1-->4) linkages in the main chain and alpha-(1-->6) linkages at the non-reducing ends. However, when the reaction mixture was incubated for 96h, most of these products were converted into oligosaccharides with DP2 to DP5 consisting of only alpha-(1-->6) linkages. These results suggested that A. niger transglucosidase rapidly transferred glucosyl residues to maltooligosaccharides, and gradually hydrolyzed both alpha-(1-->4) linkages and alpha-(1-->6) linkages at the non-reducing end, and transformed these into smaller molecules of mainly alpha-(1-->6) linkages.
Ota
Masafumi
M
Institute of Life Sciences, Ajinomoto Co., Inc., Suzuki-cho, Kawasaki, Japan. masafumi_oota@ajinomoto.com
Okamoto
Takeshi
T
Wakabayashi
Hidehiko
H
D001234:Aspergillus niger / Q000201:enzymology*; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D005964:Glucosyltransferases / Q000378:metabolism*; D008320:Maltose / Q000737:chemistry / Q000378:metabolism*; D008745:Methylation; D008958:Models, Molecular; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization
D009844:Oligosaccharides; C021705:maltooligosaccharides; D008320:Maltose; D005964:Glucosyltransferases