Figure 2.

Schematic representation of the cytosolic biosynthesis of ¹⁵N-labeled N-acetyl hexosamines that will be further used inside the Golgi apparatus for building up the GAG backbones in proteoglycans. The names of the enzymes are fully written in upper cases while the substrates and products are mostly written in lower cases. The ¹⁵N-labeled sites are indicated with red asterisks. For more details about GAG biosynthesis see also Sugahara et al., 2003³¹, or Esko and Lindahl, 2001³⁶.