Strategy for Controlled Chemoenzymatic Synthesis

SCHEME 9.3 Substrate specificity of C5-epi. (a) C5-epi recognition site resulting to irrevesible epimerization. (b) C5-epi recognition site resulting to revesible epimerization. (c) Site not acted upon by C5-epi. 

SCHEME 9.4 Enzymatic synthesis of PAPS starting from Na2S04 and ATP. Pi, phosphate PPi, pyrophosphate. 

Chemoenzymatic approach served as an alternative method for the synthesis of complex carbohydrate-containing molecules. The use of biosynthetic enzymes not only provides high regioselectivity and stereoselectivity for the formation of glycosidic bonds but also solves the problems of protection and deprotection steps required by chemical synthesis. The discovery of bacterial counterparts and the advance in bioengineering technology led to breakthroughs in complex carbohydrate synthesis. 

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