The structures of phosphoryl oligosaccharides prepared from potato starch

In the previous study, we proposed that phosphoryl oligosaccharides (POs) prepared from potato starch had an inhibitory effect on the formation of a calcium phosphate precipitate in vitro. In this study, we investigated the structures of the phosphoryl oligosaccharide-1 (PO-1) fraction that was the main component of POs, By treating with bacterial saccharifying alpha-amylase (BSA) after glucoamylase (GA), the PO-1 fraction produced 3(2)-phosphoryl maltotriose from 3-phosphoryl oligosaccharides, and 6(3)-phosphoryl maltotriose from 6-phosphoryl oligosaccharides. These products were characterized spectrometrically as well as chemically, including measurement of the amounts of the non-reducing-terminal residue, reducing-terminal residue, and organic phosphate, A small amount of 6(2)-phosphoryl maltose was also detected after treating with GA alone, indicating that 6(2)-phosphoryl maltotriose existed in the PO-1 fraction, According to the reaction specificities of GA and BSA, we conclude that the PO-1 fraction was made up of 3-phosphoryl oligosaccharides (3(3)-phosphoryl maltotetraose and 3(4)-phosphoryl maltopentaose) and 6-phosphoryl oligosaccharides (6(3)-phosphoryl maltotriose, 6(2)-phosphoryl maltotriose, 6(3)-phosphoryl maltotetraose, and 6(4)-phosphoryl maltopentaose).