Fig. 3.

Incorporation of chemical reporter groups in nucleotide sugars. (A) Incubation of human dermal fibroblasts for 48 h with 15 μM Ac₄ManNPoc and Ac₅NeuNPoc results in metabolic labeling of both UDP-HexNPoc and CMP-NeuNPoc, whereas these nucleotide sugars were absent from 15 μM Ac₅NeuNAc (controls). (B) Formation of CMP-3F_ax-NeuNAc by feeding B16-F10 cells with Ac₅-3F_ax-NeuNAc for 24 h and not by control incubations. (C) Time-dependent formation of CMP-3F_ax-NeuNAc. (D) Shown are the de novo CMP-NeuNAc biosynthesis pathway and the salvage pathway of GlcNAc. Indicated in blue arrows is the metabolic route of incorporation of ManNPoc, in red of NeuNPoc and in green of 3F_ax-NeuNAc.