Q54NJ8 · HPRT_DICDI
- ProteinHypoxanthine-guanine phosphoribosyltransferase
- GenehprT
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids180 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score4/5
Function
function
Converts guanine to guanosine monophosphate, and hypoxanthine to inosine monophosphate. Transfers the 5-phosphoribosyl group from 5-phosphoribosylpyrophosphate onto the purine. Plays a central role in the generation of purine nucleotides through the purine salvage pathway (By similarity).
Catalytic activity
- diphosphate + IMP = 5-phospho-alpha-D-ribose 1-diphosphate + hypoxanthine
Cofactor
Note: Binds 2 magnesium ions per subunit. The magnesium ions are essentially bound to the substrate and have few direct interactions with the protein.
Kinetics
KM | SUBSTRATE | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|---|
55.5 μM | hypoxanthine |
Vmax | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|
34.3 nmol/min/mg |
When guanine is used as the substrate, the rate of nucleotide formation is 50% that with hypoxanthine as the substrate.
Pathway
Purine metabolism; IMP biosynthesis via salvage pathway; IMP from hypoxanthine: step 1/1.
Features
Showing features for binding site, active site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 40 | GMP (UniProtKB | ChEBI) | ||||
Sequence: K | ||||||
Binding site | 99-107 | GMP (UniProtKB | ChEBI) | ||||
Sequence: EDIVDSGLT | ||||||
Active site | 103 | Proton acceptor | ||||
Sequence: D | ||||||
Binding site | 131 | GMP (UniProtKB | ChEBI) | ||||
Sequence: K | ||||||
Binding site | 159 | GMP (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Binding site | 159 | Mg2+ (UniProtKB | ChEBI) | ||||
Sequence: D |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | cytosol | |
Molecular Function | guanine phosphoribosyltransferase activity | |
Molecular Function | hypoxanthine phosphoribosyltransferase activity | |
Molecular Function | magnesium ion binding | |
Molecular Function | nucleotide binding | |
Biological Process | GMP salvage | |
Biological Process | guanine salvage | |
Biological Process | hypoxanthine metabolic process | |
Biological Process | IMP salvage | |
Biological Process | purine ribonucleoside salvage |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameHypoxanthine-guanine phosphoribosyltransferase
- EC number
- Short namesHGPRT; HGPRTase
Gene names
Organism names
- Strain
- Taxonomic lineageEukaryota > Amoebozoa > Evosea > Eumycetozoa > Dictyostelia > Dictyosteliales > Dictyosteliaceae > Dictyostelium
Accessions
- Primary accessionQ54NJ8
Proteomes
Organism-specific databases
Subcellular Location
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000328334 | 1-180 | Hypoxanthine-guanine phosphoribosyltransferase | |||
Sequence: MSREVIFTEKEIKERVSELGRQITQDYKDSKNLVLVGILKGSFVFMSDLVRSIHLPNTNVSLEFMSISSYGAETSSSGVIRIMMDLRTSIEGKDVLIIEDIVDSGLTLKHLMELLNHRNPNSLHTAVLLRKKEGLKVEVPVKYMGFDIPMVFIIGYGLDFAENYRELPYLGELKEECYKK |
Proteomic databases
Interaction
Protein-protein interaction databases
Structure
Sequence
- Sequence statusComplete
- Length180
- Mass (Da)20,536
- Last updated2005-05-24 v1
- Checksum68D542EEEE7B6D2F
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
AAFI02000075 EMBL· GenBank· DDBJ | EAL64853.1 EMBL· GenBank· DDBJ | Genomic DNA |