Chemoenzymatic synthesis of UDP-N-acetyl-α-D-galactosamine

Article abstract of DOI:10.1016/S0008-6215(97)10077-5

A novel chemoenzymatic synthesis of UDP-N-acetyl-α-D-galactosamine starting from uridine 5'-monophosphate (UMP) and sucrose is reported. In an enzymatic repetitive batch mode UDP-glucose was generated in situ from UMP and sucrose by the combination of nucleoside monophosphate kinase (EC 2.7.7.4) and sucrose synthase (EC 2.4.1.13). The transfer of UMP from UDP- glucose by galactose-1-phosphate uridyltransferase (EC 2.7.7.12) yielded UDP- α-D-galactosamine. The equilibrium of the synthesis was forced to the product side by the addition of phosphoglucomutase (EC 2.7.5.1) and glucose- 6-phosphate dehydrogenase (EC 1.1.1.49). Pyruvate kinase (EC 2.7.1.40) and lactate dehydrogenase (EC 1.1.1.27) were used to regenerate UTP and the cofactor NAD. The yield for the enzymatic step was 42%. Finally, UDP-α-D- galactosamine was acetylated chemically with N-acetoxysuccinimide. Product isolation was accomplished by anion-exchange chromatography and gel filtration. The overall yield was 34% and 82 mg UDP-N-acetyl-α-D- galactosamine were isolated.