Positively regulates nitric oxide synthesis in umbilical vein endothelial cells (HUVECs). May be involved in dopamine synthesis. May modify pain sensitivity and persistence. Isoform GCH-1 is the functional enzyme, the potential function of the enzymatically inactive isoforms remains unknown.
Specificity
Natural and recombinant Human GTP cyclohydrolase 1
Toroid-shaped homodecamer, composed of a dimer of pentamers. The inactive isoforms also form decamers and may possibly be incorporated into GCH1 heterodecamers, decreasing enzyme stability and activity. Interacts with AHSA1 and GCHFR/GFRP.