Monitoring individual UGlcNAcDH and UXNAcS assay by real-time one-dimensional NMR. The single-enzyme assay of UGlcNAcDH is shown in panel 1, and that of UXNAcS is shown in panel 2. All reactions were performed at 37 °C. The selected regions for the diagnostic peaks for NAD+, NADH, and the anomeric protons of the NDP-sugars are shown between 5.4 and 6.2 ppm at 5 min or 60 min after each reaction was initiated. The labeling for NAD+ and NADH protons refers to the corresponding compounds shown above. Peaks labeled as I, II, or III indicate the anomeric protons of UDP-GlcNAc, UDP-GlcNAcA, or UDP-XylNAc, respectively. Peaks marked by an asterisk (from 5.9 to 6.0 ppm) in panel 1 are the mixture of signals for Rib-H1′ and Ura-H5 protons of UDP-GlcNAc and UDP-GlcNAcA. Peaks marked by a double asterisk (from 5.9 to 6.0 ppm) in panel 2 are the mixture of signals for Rib-H1′ and Ura-H5 protons of UDP-GlcNAcA and UDP-XylNAc.