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Oxidoreductases | Transferases | Hydrolases | Lyases | Isomerases | Ligases |
Basic Information |
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Enzyme Number | 3.5.4.16 |
Official Name | GTP cyclohydrolase I |
Name from literature | GTP cyclohydrolase 1 |
Pathway from literature | BH4 synthesis/the biosynthesis of tetrahydrobiopterin (BH(4)),a natural cofactor for tyrosine and tryptophan hydroxylases |
Pathway from KEGG |
Metabolism of Cofactors and Vitamins; Folate biosynthesis; map00790 |
Organisms | Human (9606) |
Genome localization | 14q22.1-q22.2[2643 ], |
Comments | The reaction involves hydrolysis of two C-N bonds and isomerization of the pentose unit; the recyclization may be non-enzymic. This enzyme is involved in the de novo synthesis of tetrahydrobiopterin from GTP, with the other enzymes involved being EC 1.1.1.153 (sepiapterin reductase) and EC 4.2.3.12 (6-pyruvoyltetrahydropterin synthase) [3]. |
Rate-limiting Description | "BACKGROUND: GTP-cyclohydrolase I, encoded by the GCH1 gene, is the rate-limiting enzyme in the biosynthesis of BH4, an eNOS cofactor important for maintaining enzymatic coupling." (18598896) |
Regulatory Information |
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Regulatory type | Detail |
transcriptional factor;"basic region leucine zipper transcription factors(10538,116071)" | "GTP cyclohydrolase I gene transcription is regulated by basic region leucine zipper transcription factors" (16149046) |
phosphorylation; | P30793 |
transcriptional level;TNF-alpha(7124) | "Incubating HUVECs with tumor necrosis factor (TNF-alpha) was observed to increase GTPCH mRNA while decreasing eNOS mRNA." (12588756) |
Gene ontology |
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Gene ontology |
GO:0034612 (P) response to tumor necrosis factor [P30793 ]; |
Disease relevance |
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Disease |
Defects in GCH1 are the cause of atypical severe phenylketonuria (PKU) [MIM:233910]. It is a disease characterized by hyperphenylalaninemia (HPA), progressive neurologic illness with severe muscular hypotonia [P30793 ]; |
Links |
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SwissProt | |
Entrez Gene | |
HPRD |
Copyright 2009, Center for Bioinformatics | |||
Last Modified: 2009-03-24 | |||
Design by Zhao Min |