Fucose configuration

In the condensed form, the configurational symbol and the letter denoting ring size are omitted. It is understood that the configuration is D (with the exception of fucose and iduronic acid which are usually L) and that the rings are in pyranose form unless otherwise specified. The anomeric descriptor is written in the parentheses with the locants. 

A more general access to biologically important and structurally more diverse aldose isomers makes use of ketol isomerases for the enzymatic interconversion of ketoses to aldoses. For a full realization of the concept of enzymatic stereodivergent carbohydrate synthesis, the stereochemically complementary i-rhamnose (Rhal EC 5.3.1.14) and i-fucose isomerases (Fuel EC 5.3.1.3) from E. coli have been shown to display a relaxed substrate tolerance [16,99,113,131]. Both enzymes convert sugars and their derivatives that have a common (3 J )-OH configuration, but may deviate in... 

Deoxygalactose (fucose) and arabinose both exist in Nature in d and l forms, and both are related in configuration to the corresponding galactoses. 

L-Fucose oxime (XVII), with the same spatial configuration as L-galactose oxime, is exceptional in that it gives a cyclic li-fucose oxime pentaacetate at low temperature the nitrile is formed when higher temperatures are employed. 

Fucosyltransferases (glycosyltransferases) promote the transfer of fucose from GDP-fucose onto a saccharidic acceptor. This transfer occurs with inversion of the configuration of the anomeric carbon. The inhibition has been studied with fluorinated substrates. GDP-2-fluoro-2-deoxyfucoses (GDP-2F-fucose) and GDP-6-fluoro-6-deoxyfucoses (GDP-6F-fucose) are competitive inhibitors. The values are close to or less than that of (Figure 1.29)P The very close values of GDP-2F-fucose... 

As L-fucose is in the pyranosyl form and the a configuration in almost all, naturally occurring, complex carbohydrates, there is a challenge to synthesize oligosaccharides of this type. A variety of approaches has been developed in different laboratories in order to achieve this aim, and to attain reactions having high degrees of stereospecificity. 

The presence of fucose or of methyl ethers of fucose has been reported in many polysaccharides, but the configuration of the sugar has not always been established, as identification has often been based solely on chromatographic data. Great advances have been made with the introduction of new techniques for the elucidation of structures of... 

Abbreviations used in the figures are given in parentheses. All sugars except fucose (Fuc) are of the D-configuration. 

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