Q8KES3 · SPRE_CHLTE
- ProteinSepiapterin reductase
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids244 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
function
Catalyzes the final reductions in tetra-hydrobiopterin biosynthesis to form 5,6,7,8-tetrahydrobiopterin.
Catalytic activity
- L-threo-7,8-dihydrobiopterin + NADP+ = H+ + NADPH + sepiapterin
Activity regulation
Slightly inhibited by N-acetyldopamine but not by N-acetylserotonin or melatonin.
Kinetics
KM | SUBSTRATE | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|---|
21 μM | sepiapterin | 8.8 | 45 | |||
0.18 μM | sepiapterin | 6.5 | 37 | |||
6.2 μM | NADPH | 8.8 | 45 |
Vmax | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|
12 pmol/min/mg | 37 | for the reverse reaction reducing sepapterin |
For the reverse reaction, accepts L-threo-dihydrobiopterin, D-threo-dihydrobiopterin, L-threo-dihydroneopterin, dihydrotepidopterin and L-erythro-dihydrobiopterin as substrates.
pH Dependence
Optimum pH is around 8.8. Activity drops sharply above and below the optimum and is absent at pH 3 and virtually so at pH 10.6.
Temperature Dependence
Optimum temperature is 50 degrees Celsius. Stable at 25 and 50 degrees Celsius for 2 h but loses activity at 70 degrees Celsius in 20 minutes.
Features
Showing features for binding site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 9-15 | NADP+ (UniProtKB | ChEBI) | ||||
Sequence: GAGKGIG | ||||||
Binding site | 40-42 | NADP+ (UniProtKB | ChEBI) | ||||
Sequence: SRT | ||||||
Binding site | 66-67 | NADP+ (UniProtKB | ChEBI) | ||||
Sequence: DI | ||||||
Binding site | 93 | NADP+ (UniProtKB | ChEBI) | ||||
Sequence: N | ||||||
Binding site | 99 | substrate | ||||
Sequence: F | ||||||
Binding site | 116 | NADP+ (UniProtKB | ChEBI) | ||||
Sequence: T | ||||||
Binding site | 145 | substrate | ||||
Sequence: S | ||||||
Binding site | 158 | NADP+ (UniProtKB | ChEBI) | ||||
Sequence: Y | ||||||
Binding site | 158 | substrate | ||||
Sequence: Y | ||||||
Binding site | 162 | NADP+ (UniProtKB | ChEBI) | ||||
Sequence: K | ||||||
Binding site | 191-196 | NADP+ (UniProtKB | ChEBI) | ||||
Sequence: VYTPMW | ||||||
Binding site | 196 | substrate | ||||
Sequence: W |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | cytoplasm | |
Molecular Function | nucleotide binding | |
Molecular Function | oxidoreductase activity |
Keywords
- Molecular function
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameSepiapterin reductase
- EC number
- Short namesSPR ; cSR
Gene names
Organism names
- Strain
- Taxonomic lineageBacteria > Chlorobiota > Chlorobiia > Chlorobiales > Chlorobiaceae > Chlorobaculum
Accessions
- Primary accessionQ8KES3
Proteomes
Subcellular Location
Phenotypes & Variants
Features
Showing features for mutagenesis.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Mutagenesis | 99 | Drastically reduces activity. Complete loss of activity; when associated with A-196. | ||||
Sequence: F → A | ||||||
Mutagenesis | 196 | Drastically reduces activity. Complete loss of activity; when associated with A-99. | ||||
Sequence: W → A |
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000424153 | 1-244 | Sepiapterin reductase | |||
Sequence: MKHILLITGAGKGIGRAIALEFARAARHHPDFEPVLVLSSRTAADLEKISLECRAEGALTDTITADISDMADVRRLTTHIVERYGHIDCLVNNAGVGRFGALSDLTEEDFDYTMNTNLKGTFFLTQALFALMERQHSGHIFFITSVAATKAFRHSSIYCMSKFGQRGLVETMRLYARKCNVRITDVQPGAVYTPMWGKVDDEMQALMMMPEDIAAPVVQAYLQPSRTVVEEIILRPTSGDIQDD |
Interaction
Structure
Sequence
- Sequence statusComplete
- Length244
- Mass (Da)27,114
- Last updated2002-10-01 v1
- Checksum754CE7BC0363D9DA
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
AE006470 EMBL· GenBank· DDBJ | AAM71851.1 EMBL· GenBank· DDBJ | Genomic DNA |