In Arabidopsis, the orthologous genes are experimentally shown to be localized in the Golgi.
Converts UDP-N-acetyl-D-glucosamine into UDP-N-acetyl-D-galactosamine.
Converts GDP-D-mannose into GDP-4-dehydro-6-deoxy-D-mannose.
UDP-D-xylose is converted to UDP-L-arabinopyranose by enzymatic activity of UDP-d-Xylose 4-Epimerase. This reaction is reversible.