69429-20-5

Upstream product

• 1263-76-9 Maltotetraose 
• 59-56-3 α-D-glucopyranosyl-1-phosphate 
• 1980-14-9 maltoheptaose 
• 6401-81-6 maltotriose 
• 1184-46-9 Maltohexaose 
• 528-50-7 cellobiose 
• 2106-10-7 1-deoxy-1-fluoro-α-D-glucose 

Downstream Products

• 50-99-7 D-glucose 
• 492-62-6 alpha-D-glucopyranose 
• 345319-76-8 5-O-α-D-glucopyranosyl-(+)-catechin 
• 345319-75-7 (+)-catechin 7-α-O-glucoside 
• 66068-38-0 p‐nitrophenyl‐α‐D-maltopentoglycoside 
• 66146-31-4 p-Nitrophenyl α-maltopentaoside 
• 492-61-5 β-D-glucose 

Relevant academic research and scientific papers

POLYSACCHARIDES OF Eremurus. XV. STRUCTURE OF THE GLUCOMANNAN OF Eremurus lactiflorus.

Ten oligosaccharides have been isolated from the products of the partial hydrolysis of a native acetylated glucomannan obtained from Eremurus lactiflorus O.Fedtsch.Their structures have been studied with the aid of acid hydrolysis before and after reduction with NaBH4, by the GLC method, and also by chromatography with markers.The compositions and sequence of the monomers in tetra- and heptaoligosaccharides have been determined by the 13C NMR method.The glucomannan from the E. lactiflorus differs from the Eremurus glucomanans studied previously by the ratio of monosaccharides, the presence of O-Ac groups, the degree of polymerization, and the presence of a cellobiose unit (Glcp-Glcp) in the polymer chain.The repeating unit consists of 14 hexose residues.

Efficient chemoenzymatic oligosaccharide synthesis by reverse phosphorolysis using cellobiose phosphorylase and cellodextrin phosphorylase from Clostridium thermocellum

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.

Chemoenzymic synthesis of (1→3,1→4)-β-D-glucooligosaccharides for subsite mapping of (1→3,1→4)-β-D-glucan endohydrolases

A series of unsubstituted (1→3,1→4)-β-D-glucooligosaccharides, designed for subsite mapping in which the number of glucosyl-binding subsites and the subsite-binding/transition state activation affinities at individual subsites of plant and bacterial (1→3,1→4)-β-D-glucan 4-glucanohydrolases (EC 3.2.1.73) can be determined, has been synthesised through chemical and enzymic procedures. A recombinant (1→3,1→4)-β-D-glucan 4-glucanohydrolase from Bacillus licheniformis has been used in organic media to catalyse the condensation of 3-O-β-D-glucopyranosyl-β-D-glucopyranosyl fluoride (Glcβ3GlcβF, compound 1) with cellobiose (Glcβ4Glc, 2), cellotriose (Glcβ4Glcβ4Glc, 3), cellotetraose (Glcβ4Glcβ4Glcβ4Glc, 4) and cellopentaose (Glcβ4Glcβ4Glcβ4Glcβ4Glc, 5), to produce the (1→3,1→4)-β-D-glucooligosaccharides, Glcβ3Glcβ4Glcβ4Glc 6, Glcβ3Glcβ4Glcβ4Glcβ4Glc 7, Glcβ3Glcβ4Glcβ4Glcβ4Glcβ4Glc 8, Glcβ3Glcβ4Glcβ4Glcβ4Glcβ4Glcβ4Glc 9. Synthesised oligosaccharides 6-9 were isolated in yields of 15-45%, compared with compound 1. In a second series of syntheses, a cellodextrin phosphorylase (EC 2.4.1.49) from Clostridium thermocellum was used to sequentially transfer glucosyl residues from α-D-glucopyranosyl phosphate 10 to the 4-position of the non-reducing terminus of the trisaccharide Glcβ3Glcβ4Glc 11, to generate the (1→3,1→4)-β-D-glucooligosaccharides, Glcβ4Glcβ3Glcβ4Glc 12, Glcβ4Glcβ4Glcβ3Glcβ4Glc 13, Glcβ4Glcβ4Glcβ4Glcβ3Glcβ4Glc 14 in 14, 10 and 5% yield, respectively, from compound 11.

Determination of kinetic parameters for maltotriose and higher malto-oligosaccharides in the reactions catalyzed by α-D-glucan phosphorylase from potato

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.

ELECTROCHEMICAL DETECTION OF REDUCING CARBOHYDRATES PRODUCED BY THE TRANSFERASE ACTION OF YEAST DEBRANCHING ENZYME ON MALTOSACCHARIDES

A sensitive method for the detection of maltosaccharides up to maltoheptaose is based on an electrochemical detector using bis(1,10-phenanthroline)-copper(II) in the post column reaction after h.p.l.c. on an amino-bonded column.This method has been used for the analysis of the maltosyl and maltotriosyl transferase action of the yeast debranching enzyme with maltosaccharides as the substrates.The smallest donor substrate for maltosyl transfer was maltotetraose, and maltopentaose, maltohexaose, and maltoheptaose were donor substrates for both maltosyl and maltotriosyl transfers.Maltosyl residues were transferred in preference to maltotriosyl residues from maltopentaose, but maltotriosyl residues were transferred prefentially from maltohexaose and maltoheptaose.Maltotriose is an acceptor but not a donor of maltosyl and maltotriosyl transfers.

KINETICS OF ENZYMIC HYDROLYSIS OF MALTO-OLIGOSACCHARIDES: A COMPARISON WITH ACID HYDROLYSIS

The hydrolysis of malto-oligosaccharides G3-G6 catalysed by porcine pancreatic alpha-amylase was investigated kinetically at 25 deg C.Kinetic parameters corresponding to different positions of enzymic attack were determined and product inhibition was evaluated.The enzymic hydrolysis was compared in terms of reaction rate and pattern of action with hydrolysis in 0.1M H2SO4 at 70 deg C.Mathematical models for the mechanism of hydrolysis were developed and a good rationalisation of the experimental result was achieved.