1668-09-3Relevant articles and documents
Determination of kinetic parameters for maltotriose and higher malto-oligosaccharides in the reactions catalyzed by α-D-glucan phosphorylase from potato
Suganuma,Kitazono,Yoshinaga,Fujimoto,Nagahama
, p. 213 - 220 (1991)
For kinetic studies on its synthetic and phosphorolytic reactions, α-D-glucan phosphorylase from potatoes was purified chromatographically until free of D-enzyme. Purified maltotriose (G3) is a poor primer in the phosphorylase-catalyzed synthetic reaction, showing an anomalous time course and making previous attempts to determine its kinetic parameters unsuccessful. In the present work the true rate of the G3-primed reaction was obtained from linear plots obtained by incorporating a sufficient quantity of β-amylase in the digest to eliminate the more rapidly reacting G4 formed from the G3. A K(m) value of 9.4 ± 0.8 mM for G3 was calculated from the data by a nonlinear least-squares method. Kinetic parameters for a series of higher malto-oligosaccharides (G4-G8) were also determined in both the synthetic and the phosphorolytic directions. A large change in the values of K(m) and V/e was seen on going from G3 to G4 for the synthetic reaction, and from G4 to G5 for the phosphorolytic. For the higher saccharides the V/e values do not vary strongly with increasing d.p., while the K(m) values tend to decrease, as has seen in the reactions of other plant phosphorylases. For kinetic studies on its synthetic and phosphorolytic reactions α-D-glucan phosphorylase from potatoes was purified chromatographically until free of D-enzyme. Purified maltotriose (G3) is a poor primer in the phosphorylase-catalyzed synthetic reaction, showing an anomalous time course and making previous attempts to determine its kinetic parameters unsuccessful. In the present work the true rate of the G3-primed reaction was obtained from linear plots obtained by incorporating a sufficient quantity of β-amylase in the digest to eliminate the more rapidly reacting G4 formed from the G4 A Km value of 9.4 ± 0.8 mM for G3 was calculated from the data by a nonlinear least-squares method. Kinetic parameters for a series of higher malto-oligosaccharides (G4-G3) were also determined in both the synthetic and the phosphorolytic directions. A large change in the values of Km and V/e was seen on going from G3 to G4 for the synthetic reaction, and from G4 to G3 for the phosphorolytic. For the higher saccharides the V/e values do not vary strongly with increasing d.p.. while the Km values tend to decrease, as has seen in the reactions of other plant phosphorylases.
Automated Assembly of Starch and Glycogen Polysaccharides
Delbianco, Martina,Seeberger, Peter H.,Zhu, Yuntao
supporting information, p. 9758 - 9768 (2021/06/30)
Polysaccharides are Nature's most abundant biomaterials essential for plant cell wall construction and energy storage. Seemingly minor structural differences result in entirely different functions: cellulose, a β (1-4) linked glucose polymer, forms fibrils that can support large trees, while amylose, an α (1-4) linked glucose polymer forms soft hollow fibers used for energy storage. A detailed understanding of polysaccharide structures requires pure materials that cannot be isolated from natural sources. Automated Glycan Assembly provides quick access to trans-linked glycans analogues of cellulose, but the stereoselective installation of multiple cis-glycosidic linkages present in amylose has not been possible to date. Here, we identify thioglycoside building blocks with different protecting group patterns that, in concert with temperature and solvent control, achieve excellent stereoselectivity during the synthesis of linear and branched α-glucan polymers with up to 20 cis-glycosidic linkages. The molecules prepared with the new method will serve as probes to understand the biosynthesis and the structure of α-glucans.
Efficient chemoenzymatic oligosaccharide synthesis by reverse phosphorolysis using cellobiose phosphorylase and cellodextrin phosphorylase from Clostridium thermocellum
Nakai, Hiroyuki,Hachem, Maher Abou,Petersen, Bent O.,Westphal, Yvonne,Mannerstedt, Karin,Baumann, Martin J.,Dilokpimol, Adiphol,Schols, Henk A.,Duus, Jens ?.,Svensson, Birte
experimental part, p. 1818 - 1826 (2011/08/21)
Inverting cellobiose phosphorylase (CtCBP) and cellodextrin phosphorylase (CtCDP) from Clostridium thermocellum ATCC27405 of glycoside hydrolase family 94 catalysed reverse phosphorolysis to produce cellobiose and cellodextrins in 57% and 48% yield from α-d-glucose 1-phosphate as donor with glucose and cellobiose as acceptor, respectively. Use of α-d-glucosyl 1-fluoride as donor increased product yields to 98% for CtCBP and 68% for CtCDP. CtCBP showed broad acceptor specificity forming β-glucosyl disaccharides with β-(1→4)- regioselectivity from five monosaccharides as well as branched β-glucosyl trisaccharides with β-(1→4)-regioselectivity from three (1→6)-linked disaccharides. CtCDP showed strict β-(1→4)-regioselectivity and catalysed linear chain extension of the three β-linked glucosyl disaccharides, cellobiose, sophorose, and laminaribiose, whereas 12 tested monosaccharides were not acceptors. Structure analysis by NMR and ESI-MS confirmed two β-glucosyl oligosaccharide product series to represent novel compounds, i.e. β-d-glucopyranosyl-[(1→4)- β-d-glucopyranosyl]n-(1→2)-d-glucopyranose, and β-d-glucopyranosyl-[(1→4)-β-d-glucopyranosyl]n- (1→3)-d-glucopyranose (n = 1-7). Multiple sequence alignment together with a modelled CtCBP structure, obtained using the crystal structure of Cellvibrio gilvus CBP in complex with glucose as a template, indicated differences in the subsite +1 region that elicit the distinct acceptor specificities of CtCBP and CtCDP. Thus Glu636 of CtCBP recognized the C1 hydroxyl of β-glucose at subsite +1, while in CtCDP the presence of Ala800 conferred more space, which allowed accommodation of C1 substituted disaccharide acceptors at the corresponding subsites +1 and +2. Furthermore, CtCBP has a short Glu496-Thr500 loop that permitted the C6 hydroxyl of glucose at subsite +1 to be exposed to solvent, whereas the corresponding longer loop Thr637-Lys648 in CtCDP blocks binding of C6-linked disaccharides as acceptors at subsite +1. High yields in chemoenzymatic synthesis, a novel regioselectivity, and novel oligosaccharides including products of CtCDP catalysed oligosaccharide oligomerisation using α-d-glucosyl 1-fluoride, all together contribute to the formation of an excellent basis for rational engineering of CBP and CDP to produce desired oligosaccharides.
Kinetics of maltooligosaccharide hydrolysis in subcritical water
Khajavi, Shabnam Haghighat,Ota, Shuji,Kimura, Yukitaka,Adachi, Shuji
, p. 3663 - 3667 (2007/10/03)
The kinetics of the hydrolysis of maltooligosaccharides with a degree of polymerization (DP) of 3-6 in subcritical water was studied using a tubular reactor at temperatures between 200 and 260°C and at a constant pressure of 10 MPa. The maltooligosaccharide disappearance and product formation at residence times shorter than 50 s could be expressed by first-order kinetics. The rate constants for the hydrolysis of each maltooligosaccharide were evaluated. There was a tendency that the exo-site glucosidic bond was hydrolyzed faster than the endo-site one irrespective of the DP of the maltooligosaccharide. The hydrolysis of the maltooligosaccharides was consecutively preceded, and the time dependence of the hydrolysis for maltooligosaccharides with different DPs could be calculated by simultaneously solving the mass balance equations for all the possible saccharides.
