  2.4.1.229 | UDP-N-acetyl-alpha-D-glucosamine + [Skp1-protein]-trans-4-hydroxy-L-proline = UDP + [Skp1-protein]-O-(N-acetyl-alpha-D-glucosaminyl)-trans-4-hydroxy-L-proline |
Requires dithiothreitol and a divalent cation for activity. This enzyme commences the building up of a pentasaccharide (Galalpha1-6Galalpha1-L-Fucalpha1-2Galbeta1-3GlcNAc) on Hyp-143 of the Dictyostelium protein Skp1, which is required for the ubiquitination of cell-cycle regulatory proteins and transcription factors. The fucose residue is probably in the alpha configuration. The specificity of the enzyme for Skp1-Hyp-143 and its high affinity for this substrate suggests that it is the GlcNAc-transferase that modifies Skp1 in vivo |
- |
