Chemical synthesis of a dual branched malto-decaose: a potential substrate for alpha-amylases.
A convergent block strategy for general use in efficient synthesis of complex alpha-(1-->4)- and alpha-(1-->6)-malto-oligosaccharides is demonstrated with the first chemical synthesis of a malto-oligosaccharide, the decasaccharide 6,6''''-bis(alpha-maltosyl)-maltohexaose, with two branch points. Using this chemically defined branched oligosaccharide as a substrate, the cleavage pattern of seven different alpha-amylases were investigated. Alpha-amylases from human saliva, porcine pancreas, barley alpha-amylase 2 and recombinant barley alpha-amylase 1 all hydrolysed the decasaccharide selectively. This resulted in a branched hexasaccharide and a branched tetrasaccharide. Alpha-amylases from Asperagillus oryzae, Bacillus licheniformis and Bacillus sp. cleaved the decasaccharide at two distinct sites, either producing two branched pentasaccharides, or a branched hexasaccharide and a branched tetrasaccharide. In addition, the enzymes were tested on the single-branched octasaccharide 6-alpha-maltosyl-maltohexaose, which was prepared from 6,6''''-bis(alpha-maltosyl)-maltohexaose by treatment with malt limit dextrinase. A similar cleavage pattern to that found for the corresponding linear malto-oligosaccharide substrate was observed.
Damager
Iben
I
The Carbohydrate Chemistry Group, Plant Biochemistry Laboratory, Department of Plant Biology and Center for Molecular Plant Physiology, The Royal Veterinary and Agricultural University, 1871 Frederiksberg C, Copenhagen, Denmark.
Jensen
Morten T
MT
Olsen
Carl E
CE
Blennow
Andreas
A
Møller
Birger L
BL
Svensson
Birte
B
Motawia
Mohammed S
MS
D002240:Carbohydrate Sequence; D002853:Chromatography, Liquid; D007527:Isoenzymes / Q000378:metabolism; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism*; D000516:alpha-Amylases / Q000378:metabolism*
D007527:Isoenzymes; D009844:Oligosaccharides; C021705:maltooligosaccharides; D000516:alpha-Amylases