7265-01-2Relevant academic research and scientific papers
Solid-phase oligosaccharide and glycopeptide synthesis using glycosynthases
Tolborg, Jakob F.,Petersen, Lars,Jensen, Knud J.,Mayer, Christoph,Jakeman, David L.,Warren, R. Antony J.,Withers, Stephen G.
, p. 4143 - 4149 (2007/10/03)
Enzymatic approaches for the preparation of oligosaccharides are interesting alternatives to traditional chemical synthesis, the main advantage being the regio- and stereoselectivity offered without the need for protecting groups. The use of solid-phase techniques offers easy workup procedures and the prospect of automatability. Here, we report the first application of glycosynthases to solid-phase oligosaccharide synthesis by use of the 51 kDa serine and glycine mutants of Agrobacterium sp. β-glucosidase, Abg E358S and E358G. Acceptors were linked to PEGA resin through a backbone amide linker (BAL), and using these mutated enzymes, a galactose moiety was transferred from a donor sugar, α-D-galactosyl fluoride, with high efficiency (>90%) together with excellent recovery of material. Furthermore, it was demonstrated that a resin-bound model glycopeptide was also an acceptor for the glycosynthase.
New organogelators bearing both sugar and cholesterol units: An approach toward molecular design of universal gelators
Amaike,Kobayashi,Shinkai
, p. 2553 - 2558 (2007/10/03)
The gelators of organic solvents are classified into two categories on the basis of their basic intermolecular forces: hydrogen-bonded or nonhydrogen-bonded. To utilize these two interactions cooperatively for organogel formation we newly synthesized seven gelators (1-7) and two reference compounds (8 and 9) which have both a cholesterol moiety and a saccharide moiety within one molecule. The solubility of 1-7 changed drastically from totally insoluble one to very soluble one depending on the saccharide absolute configuration. In general, the gelator became very insoluble when it includes many equatorial OH groups, whereas it became very soluble when it includes many axial OH groups. Gelators 2 and 5 bearing two equatorial OH groups and one axial OH group acted as good gelators and in several cases the sol-gel phase-transition temperatures (measured in a sealed tube) were higher than the boiling points. The SEM observations of the xerogels established that the stable gels contain the entangled fibrous network. These results indicate that a very stable organogel can be designed by a cooperative coagulative effect of a cholesterol-cholesterol interaction and a saccharide-saccharide interaction.
