Biocatalytic Production of Amino Carbohydrates through Oxidoreductase and Transaminase Cascades.

Plant-derived carbohydrates are an abundant renewable resource. Transformation of carbohydrates into new products， including amine-functionalized building blocks for biomaterials applications， can lower reliance on fossil resources. Herein， biocatalytic production routes to amino carbohydrates， including oligosaccharides， are demonstrated. In each case， two-step biocatalysis was performed to functionalize d-galactose-containing carbohydrates by employing the galactose oxidase from Fusarium graminearum or a pyranose dehydrogenase from Agaricus bisporus followed by the ω-transaminase from Chromobacterium violaceum (Cvi-ω-TA). Formation of 6-amino-6-deoxy-d-galactose， 2-amino-2-deoxy-d-galactose， and 2-amino-2-deoxy-6-aldo-d-galactose was confirmed by mass spectrometry. The activity of Cvi-ω-TA was highest towards 6-aldo-d-galactose， for which the highest yield of 6-amino-6-deoxy-d-galactose (67 %) was achieved in reactions permitting simultaneous oxidation of d-galactose and transamination of the resulting 6-aldo-d-galactose.