Following, samples were thawed at 4°C and filtered through a MultiScreen Filter Plate (Millipore, Billerica, MA, USA) according to manufacturer’s instructions and evaluated for formation of UDP- ( 33a ) or TDP-α-D-glucose ( 33b ) by analytical reverse-phase HPLC with a 250 mm × 4.6 mm Gemini-NX 5μ C18 column (Phenomenex, Torrance, CA, USA