Biology Reference
In-Depth Information
Starting disaccharides
Trisaccharides
Tetrasaccharides
Glc-Glc-Glc
Glc-Glc-Glc-Glc
Glc-Glc
Xyl-Glc
-Glc-Glc
Glc-Xyl-Glc-Glc
Xyl-Glc-Glc
Xyl-Xyl-Glc-Glc
Glc-Glc-Xyl
Glc-Glc-Glc-Xyl
Xyl-Glc
-Glc-Xyl
Glc-Xyl
Glc-Xyl-Glc-Xyl
Xyl-Xyl-Glc-Xyl
Xyl-Glc-Xyl
Glc-Xyl-Glc
Glc-Glc-Xyl-Glc
Xyl-Glc
-Xyl-Glc
Xyl-Glc
Glc-Xyl-Xyl-Glc
Xyl-Xyl-Glc
Xyl-Xyl-Xyl-Glc
Glc-Xyl-Xyl
Glc-Glc-Xyl-Xyl
Xyl-Xyl
Xyl-Glc
-Xyl-Xyl
Glc-Xyl-Xyl-Xyl
Xyl-Xyl-Xyl-Xyl
Xyl-Xyl-Xyl
β
→
Figure 3.7
Synthesis of a library of
4)-hetero-glucose and xylose-
based oligosaccharides by the cellodextrin phosphorylase-
catalyzed glycosylation (except underlined cello- and
xylooligosaccharides); the four tetrasaccharides in parentheses
were not obtained successfully.
-(1
heterotrisaccharides and 10 of 14 possible heterotetrasaccharides.
However, it was found that it is not possible to synthesize the four
tetrasaccharides with a Xyl
→
Glc sequence at their nonreducing
ends (in parentheses in Fig. 3.7) by this enzymatic reaction.
Two enzymes exist for the phosphorolysis of trehalose: inversion
type (EC 2.4.1.64) and retention type (EC 2.4.1.231) [20,21]. The
former reversibly phosphorolyzes trehalose to form
β
-Glc-1-P and
glucose and the latter catalyzes the same reaction but with a retention
of the anomeric configuration, giving Glc-1-P and glucose (Fig. 3.8).
In an interesting application, a process is described for producing
