188003-24-9Relevant academic research and scientific papers
Mechanistic insights from substrate preference in unsaturated glucuronyl hydrolase
Jongkees, Seino A. K.,Yoo, Hayoung,Withers, Stephen G.
, p. 124 - 134 (2014)
Natural and synthetic unsaturated glucuronides were tested as substrates for Clostridium perfringens unsaturated glucuronyl hydrolase to probe its mechanism and to guide inhibitor design. Of the natural substrates, a chondroitin disaccharide substrate with sulfation of the primary alcohol on carbon 6 of its N-acetylgalactosamine moiety was found to have the highest turnover number of any substrate reported for an unsaturated glucuronyl hydrolase, with kcat=112 s-1. Synthetic aryl glycoside substrates with electron-withdrawing aglycone substituents were cleaved more slowly than those with electron-donating substituents. Similarly, an unsaturated glucuronyl fluoride was found to be a particularly poor substrate, with k cat/Km=44 nM-1 s-1 - a very unusual result for a glycoside-cleaving enzyme. These results are consistent with a transition state with positive charge at carbon 5 and the endocyclic oxygen, as anticipated in the hydration mechanism proposed. However, several analogues designed to take advantage of strong enzyme binding to such a transition state showed little to no inhibition. This result suggests that further work is required to understand the true nature of the transition state stabilised by this enzyme. Copyright
Conformational study of synthetic Δ4-uronate monosaccharides and glycosaminoglycan-derived disaccharides
Bazin, Helene G.,Capila, Ishan,Linhardt, Robert J.
, p. 135 - 144 (2007/10/03)
Sixteen Δ4-uronate monosaccharides were chemically synthesized. Their carboxy group was protected as a methyl or benzyl ester, the anomeric hydroxyl group as a benzyl glycoside and the 2 and 3 hydroxyl groups were protected with different substitution patterns as both ester and ether derivatives. Disaccharides containing Δ4-uronates were prepared from heparin using heparin lyases. Their carboxy group was unprotected or protected as a benzyl ester and the two hydroxyls in the uronate moiety were free, as O-sulfo derivatives or acylated. The conformation of these unsaturated uronate monosaccharide and disaccharide residues was studied using 1H NMR by examining interproton vic inal coupling constants. The Δ4-uronate residue adopted either the 2H1 or the 1H2 conformations. The equilibrium between these two conformers was shown to be controlled by substitution pattern.
Regio and stereoselective conversion of Δ4-uronic acids to L-ido- and D-glucopyranosiduronic acids
Bazin, Helene G.,Kerns, Robert J.,Linhardt, Robert J.
, p. 923 - 926 (2007/10/03)
Synthesis of L-ido- and D-glucopyranosiduronic acids was performed starting from protected Δ4-uronic acids 3a-f. Bromination of the C-4,5 double bond provided the trans-diaxial bromohydrin derivatives 6a-d, which were converted to the corresponding epoxides 7a-d in high yields. Direct reduction of these epoxides using borane-tetrahydrofuran complex afforded the D-glucopyranosiduronic acids 9b-d, while Lewis acid rearrangement through the C-4 keto intermediate 10b-d afforded the L-idopyranosiduronic acids 11b-d.
