Immunogen sequence: MPYLLISTQI RMEVGPTMVG DEQSDPELMQ HLGASKRRAL GNNFYEYYVD DPPRIVLDKL ERRGFRVLSM TGVGQTLVWC LHKE Highest antigen sequence identity to the following orthologs: Mouse - 93%, Rat - 94%. Mediates tetrahydrobiopterin inhibition of GTP cyclohyd