A- L-Arabinose

Fig. 7.—Predicted (- -) and Fragment (—) Circular Dichroism Spectra /3-L-Arabinose Calculated from (a) a-D-Xylose, and (b) Methyl /3-L-Aiabinoside a-L-Arabinose Calculated from (c) j3-D-Xylose, and (d) Average Calculated for /3-L-Arabinose Methyl a-L-Arabinoside Calculated from (e) Methyl /3-D-Xyloside, and (f) Methyl /3-L-Arabinoside. (Redrawn from Ref. 6.)...

D-galactose to D-galactonolactone in the presence of the coenzyme NAD+, is more specific and enzyme preparations are available for which the only other substrates are a-L-arabinose and /3-D-fucose. The generation of NADH is conveniently monitored at 340 nm and permits quantitation of the galactose ... 

Fig. B.5.1. Crystal structure of a-L-arabinose bound to the binding site of the periplasmic ABP of Escherichia coli (PDB entry 1ABE [5]). Dashed lines represent direct and indirect hydrogen bonds.

Structural changes in the protein accompany binding, as indicated by the inaccessibility of the bound L-arabinose to the aqueous environment [19]. Interestingly, unlike many other carbohydrate binding proteins that display a strict anomeric selectivity, a-L-arabinose can be equally well accommodated in the carbohydrate-binding site of this protein. In this case, however, only... 

Aryl 1-thioglycosides have also been examined for their ease of acid hydrolysis.i Pora-substituted-phenyl 1-thioglycopyranosides of fi-D-glucose, /S-D-galactose, -D-xylose, and a-L-arabinose were hydrolyzed in 3 N hydrochloric acid at 80° the rates are in the order (p-substituents) 0H>0Me>Me>H>Cl>Br>N02. This is the same as the order found for glycosides (see Table XXVI). 

Fig. 1 Crystal structures of the periplasmic L-arabinose-binding protein (ABP) of Escherichia coli complexed to a-L-arabinose (left. PDB entry lABE) and of galectin-1 complexed to A-acetyllactosamine (right, PDB entry ISLT). (From Refs. [13-15]). (View this art in color at www.dekker.com.)...

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