ChemInform Abstract: Practical Synthesis of Carbohydrates Based on Aldolases and Glycosyl Transferases

With various recombinant DNA and protein engineering techniques now available, enzyme-bad technologies are emerging as practical methods for large-scale synthesis of chiral intermediates and bioactive molecules, especially carbohydrates, oligosaccharides, their conjugates and related substances. This paper describes recent developments in the synthesis of novel monosaccharides and aza sugars based on aldolases, and the synthesis of oligosaccharides and analogs based on glycosyltransferases coupled with in sins regeneration of sugar nucleotides. As many enzymes are available for the stereocontrolled synthesis of chiral synthons (l), attention has been extended to the development of more effective and stable enzymes for the synthesis of molecules with increasing complexity (2). One class of such complex molecules are carbohydrates and their conjugates, especially those that exist on cell surfaces (3). These molecules are involved in many types of recognition phenomena (3-6); however, most of their precise functions have not been clearly identified at the molecular level. Part of the reason is that these molecules have been difficult to isolate, characterize and synthesize. Enzyme-based technology seems to be well suited for the synthesis of glycoconjugates and related substances for the study of their functions as these molecules are multifunctional and highly soluble in polar solvents, and many enzymes are available for the transformation of these molecules (7). The following describes some new technologies developed for the synthesis of sugar- and peptide- related substances based on recombinant or engineered enzymes.