GCH1 - GTP cyclohydrolase 1 - human protein (Function)
 
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Protein
Gene
References

 
GCH1 »  GTP cyclohydrolase 1   [ EC 3.5.4.16 ]
 
Protein also known as:  GTP cyclohydrolase I (GTP-CH-I).
Gene name:  GCH1
Family name: GTP cyclohydrolase I
Entry whose protein(s) existence is based on evidence at protein level
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1 122 4
GENE REF ISO

Function

 show evidences
Overview 
Positively regulates nitric oxide synthesis in umbilical vein endothelial cells (HUVECs). May be involved in dopamine synthesis. May modify pain sensitivity and persistence.  
5
  • CuratedUniProtKB
Isoform  GCH-1   Is the functional enzyme, the potential function of the enzymatically inactive isoforms remains unknown.  
5
  • CuratedUniProtKB
GO molecular function 
Calcium ion bindingdefinition[GO:0005509] silver  
  • IEAOrtholog Compara
Coenzyme bindingdefinition[GO:0050662] silver  
  • IEAOrtholog Compara
GTP bindingdefinition[GO:0005525]  
2
  • IDAUniProtKB
Isoform  GCH-1 but not isoforms  GCH-2 , GCH-3 and GCH-4   GTP cyclohydrolase I activitydefinition[GO:0003934]  
6
  • IDAUniProtKB
  • IDAMGI
GTP-dependent protein bindingdefinition[GO:0030742] silver  
  • IEAOrtholog Compara
Protein bindingdefinition[GO:0005515]  
3
  • IPIIntAct
  • IPIUniProtKB
Protein homodimerization activitydefinition[GO:0042803]  
1
  • IPIUniProtKB
Zinc ion bindingdefinition[GO:0008270]  
2
  • IDAUniProtKB
GO biological process 
7,8-dihydroneopterin 3'-triphosphate biosynthetic processdefinition[GO:0035998]  
  • IEAUniPathway
Dopamine biosynthetic processdefinition[GO:0042416]  
1
  • IDAUniProtKB
GTP catabolic processdefinition[GO:0006184]  
1
  • IDAUniProtKB
Isoform  GCH-1   Metabolic processdefinition[GO:0008152]  
1
  • IDAGOC
Negative regulation of blood pressuredefinition[GO:0045776] silver  
  • IEAOrtholog Compara
Neuromuscular process controlling posturedefinition[GO:0050884]  
1
  • IMPMGI
Nitric oxide biosynthetic processdefinition[GO:0006809]  
1
  • NASUniProtKB
Positive regulation of nitric-oxide synthase activitydefinition[GO:0051000]  
3
  • IMPUniProtKB
Protein heterooligomerizationdefinition[GO:0051291] silver  
  • IEAOrtholog Compara
Protein homooligomerizationdefinition[GO:0051260]  
1
  • IDAUniProtKB
Pteridine-containing compound biosynthetic processdefinition[GO:0042559]  
3
  • IDAUniProtKB
Regulation of blood pressuredefinition[GO:0008217]  
1
  • IMPUniProtKB
Regulation of lung blood pressuredefinition[GO:0014916] silver  
  • IEAOrtholog Compara
Response to interferon-gammadefinition[GO:0034341]  
3
  • IDAUniProtKB
Contradiction  Response to lipopolysaccharidedefinition[GO:0032496]  
3
  • IEPUniProtKB
Response to paindefinition[GO:0048265]  
  • ISSOrtholog Curator
Response to tumor necrosis factordefinition[GO:0034612]  
1
  • IDAUniProtKB
Tetrahydrobiopterin biosynthetic processdefinition[GO:0006729]  
3
  • IMPUniProtKB
Tetrahydrofolate biosynthetic processdefinition[GO:0046654] silver  
  • IEAInterPro 2 GO
Vasodilationdefinition[GO:0042311] silver  
  • IEAOrtholog Compara
Enzymatic activity 
This protein acts as an enzyme. It is known to catalyze the following reaction
EC 3.5.4.16: GTP + H(2)O formate + 2-amino-4-hydroxy-6-(erythro-1,2,3-trihydroxypropyl)-dihydropteridine triphosphate.  
3
  • CuratedUniProtKB
It is regulated in the following manner
GTP shows a positive allosteric effect, and tetrahydrobiopterin inhibits the enzyme activity. Zinc is required for catalytic activity. Inhibited by Mg(2+).  
3
  • CuratedUniProtKB
Pathways 
This protein is involved in the following pathway
According to KEGG, this protein belongs to the following pathways:
Folate biosynthesis  hsa00790+2643  
Metabolic pathways  hsa01100+2643  
According to Reactome, this protein belongs to the following pathway:
Metabolism  REACT_111217  
 
More information is available from:
 

Biophysicochemical properties

Kinetic parameters
KM 116 uM for GTP
Dependence
pH Optimum pH is 7.7 in phosphate buffer.
Temperature Relatively stable at high temperatures. Retains 50% of its activity after incubation at 70 degrees Celsius for 15 minutes.

Keywords

Biological process 
Tetrahydrobiopterin biosynthesis  definition   [KW-0783]
Molecular function 
Hydrolase  definition   [KW-0378]
Technical term 
Allosteric enzyme  definition   [KW-0021]
Reference proteome  definition   [KW-1185]
 

Further external links

Enzyme and pathway databases
SABIO-RK: P30793
Other
GeneWiki: GTP_cyclohydrolase_I
GenomeRNAi: 2643
PRO: PR:P30793