Carbohydrates turanose

The pure enzyme displayed the preference sucrose > raffinose > 1-kestose > nystose (in a ratio 100 24 10 6). Other carbohydrates such as turanose, cellobiose, melibiose, leucrose, methyl-a-D-glucopyranoside, and stachyose were also tested but their activity was negligible. Thus, the enzyme only recognized sugars containing a sucrose moiety in their chemical structure. The trisaccharide raffinose is equivalent to a sucrose molecule substituted at the C-6 hydroxyl group, whereas... 

A significantly better separation between the two disaccharides is obtained with a more complex NaOH gradient. Instead of zinc acetate, small amounts of sodium acetate are added to the mobile phase in order to elute more strongly retained saccharides within an acceptable time frame. Figure 3.236 shows a respective chromatogram with carbohydrates that are relevant for the analysis of urine to assess kidney functionality. In addition to lactose and lactulose, these carbohydrates include weso-erythritol, mannitol, sucrose, and turanose. Under these chromatographic conditions, resolution between lactose and lactulose is so large that even an excess of lactose does not prohibit clear quantitation of lactulose. 

Figure 12.1. Thin layer chromatography of the separation of carbohydrates A, chromatography of mono-, di-, and trisaccharides on Whatman K5 silica gel, using four ascents of acetonitrile/H20 (85 15, v/v) (1 16), standards, (2), D-ribose, (3) D-xylose, (4) D-fruc-tose, (5) D-xylose, (6) D-galactose, (7) sucrose, (8) turanose, (9) maltose, (10) cellobiose, (11) lactose, (12) a,a-trehalose, (13) melibiose, (14) melezitose, (15) raffinose B, chromatography of maltodextrins (d.p. 1-13) on Whatman K5, using three ascents of acetoni-trile/ethyl acetate/propanol-l/H20 (85 20 50 50) C, chromatography of isomaltodextrins (d.p. 1-11) on Whatman K5, using acetonitrile/ethyl acetate/propanol-l/H20 (85 20 50 90).

The role of hydrogen bonding in carbohydrates has been examined by molecular dynamics simulations on maltose in aqueous solution/ Ramachandran energy surfaces have been computed for leucrose and turanose (5-0- and 3-0-a-D-glucopyranosyl-D-fructopyranose, respectively) using MM3. ... 

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