Protopectinase-T: a rhamnogalacturonase able to solubilize protopectin from sugar beet.
Protopectinase-T (PPase-T), isolated from the culture broth of Trametes sanguinea, was able to release pectic substances from sugar beet by degrading rhamnogalacturonan. The smallest polysaccharide (SPS) that can serve as a substrate for PPase-T was prepared from sugar beet pulp by extraction with NaOH and digestion with alpha-L-arabinofuranosidase, alpha-L-arabinase, and beta-(1-->4)-D-galactanase. The reaction products of SPS with PPase-T were isolated by chromatography on DEAE-Toyopearl 650M and Toyopearl HW40-S columns, and analyzed by labeling the reducing ends with [3H]NaBH4 and by 13C NMR spectroscopy. The results indicated that PPase-T cleaved galactopyranosyluronic-rhamnopyranosyl linkages in SPS. Moreover, it was confirmed that the chemical structure of SPS contains a backbone based on units of [-->4)-alpha-D-GalpA-(1-->2)-alpha-L-Rha p-(1-->].
Department of Agricultural Chemistry, College of Agriculture, University of Osaka Prefecture, Japan.
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Sakamoto
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Sakai
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002473:Cell Wall / Q000378:metabolism; D004187:Disaccharides / Q000737:chemistry; D006026:Glycoside Hydrolases / Q000378:metabolism*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010368:Pectins / Q000737:chemistry* / Q000378:metabolism*; D010945:Plants, Edible / Q000201:enzymology*; D013379:Substrate Specificity
D004187:Disaccharides; D010368:Pectins; D006026:Glycoside Hydrolases; C083413:protopectinase