62499-26-7Relevant academic research and scientific papers
The building blocks of cellulose: The intrinsic conformational structures of cellobiose, its epimer, lactose, and their singly hydrated complexes
Cocinero, Emilio J.,Gamblin, David P.,Davis, Benjamin G.,Simons, John P.
supporting information; experimental part, p. 11117 - 11123 (2009/12/03)
A combination of vibrational spectroscopy conducted under molecular beam conditions and quantum chemical calculation has established the intrinsic three-dimensional structures of the cellulose disaccharide and, focusing on the critical β1,4-linkage at the nonreducing end of the growing cellulose polymer, its C-4′ epimer. Left to their own devices they both adopt a cis (anti-φ/syn-ψ) glycosidic configuration, supported in the epimer by strong, cooperative inter-ring hydrogen bonding. In the cellulose disaccharide, however, where the OH-4′(Glc) group is equatorial, the cooperativity is reduced and the corresponding inter-ring hydrogen bonding is relatively weak. The cis conformational preference is still retained in their singly hydrated complexes. In the cellulose disaccharide insertion of the water molecule at the favored binding site between OH-4′ and the neighboring hydroxyl group OH-6′ promotes a structural reorganization to create a configuration that parallels that of its unhydrated epimer and greatly strengthens the inter-ring hydrogen bonding. In the C-4′ epimer, the axial orientation of OH-4′ blocks this binding site and the bound water molecule simply adds on at the end of the (OH-O)n chain, which has a negligible effect on the (already strong) inter-ring bonding. The implications of these results are discussed with respect to the structure and insolubility of native cellulose polymers.
Optimized synthesis of specific sizes of maltodextrin glycosides by the coupling reactions of Bacillus macerans cyclomaltodextrin glucanyltransferase
Yoon, Seung-Heon,Robyt, John F.
, p. 210 - 217 (2007/10/03)
Bacillus macerans cyclomaltodextrin glucanyltransferase (CGTase, EC 2.4.1.19), in reaction with cyclomaltohexaose and methyl α-d- glucopyranoside, methyl β-d-glucopyranoside, phenyl α-d- glucopyranoside, and phenyl β-d-glucopyranoside gave four kinds of maltodextrin glycosides. The reactions were optimized by using different ratios of the individual d-glucopyranosides to cyclomaltohexaose, from 0.5 to 5.0, to obtain the maximum molar percent yields of products, which were from 68.3% to 78.6%, depending on the particular d-glucopyranoside, and also to obtain different maltodextrin chain lengths. The lower ratios of 0.5-1.0 gave a wide range of sizes from d.p. 2-17 and higher. As the molar ratio was increased from 1.0 to 3.0, the larger sizes, d.p. 9-17, decreased, and the small and intermediate sizes, d.p. 2-8, increased; as the molar ratios were increased further from 3.0 to 5.0, the large sizes completely disappeared, the intermediate sizes, d.p. 4-8, decreased, and the small sizes, d.p. 2 and 3 became predominant. A comparison is made with the synthesis of maltodextrins by the reaction of CGTase with different molar ratios of d-glucose to cyclomaltohexaose.
