FIGURE 5.

Representative chromatograms of DMB-labeled sialic acid residues from Jurkat cell lysates. Jurkat cells were treated for 72 h with 500 μm peracetylated 2-acetylamino-2-deoxy-3-O-methyl-d-mannose (10a). Contents of CMP-activated Neu5Ac were determined after sodium borohydride reduction of the cytosolic fraction. Chromatograms of treated cells (orange) and untreated cells (blue) are plotted against a standard of 14 ng of Neu5Ac. Comparing treated and untreated cells no additional fluorescence peak appeared, indicating that 10a is not metabolized into a modified sialic acid.