Ribulose-phosphate 3-epimerase
| ribulose-phosphate 3-epimerase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC number | 5.1.3.1 | ||||||||
| CAS number | 9024-20-8 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / EGO | ||||||||
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| Ribulose-phosphate 3 epimerase family | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| Symbol | Ribul_P_3_epim | ||||||||
| Pfam | PF00834 | ||||||||
| InterPro | IPR000056 | ||||||||
| PROSITE | PDOC00833 | ||||||||
| SCOP | 1rpx | ||||||||
| SUPERFAMILY | 1rpx | ||||||||
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In enzymology, a ribulose-phosphate 3-epimerase (EC 5.1.3.1) (also known as pentose-5-phosphate 3-epimerase or PPE) is the enzyme that converts D-ribulose 5-phosphate into D-xylulose 5-phosphate in Calvin's reductive pentose phosphate cycle.
- D-ribulose 5-phosphate
D-xylulose 5-phosphate
Hence, this enzyme has one substrate, D-ribulose 5-phosphate, and one product, D-xylulose 5-phosphate.
This enzyme belongs to the family of isomerases, specifically those racemases and epimerases acting on carbohydrates and derivatives.
In Alcaligenes eutrophus two copies of the gene coding for PPE are known,[1] one is chromosomally encoded P40117, the other one is on a plasmid Q04539. PPE has been found in a wide range of bacteria, archaebacteria, fungi and plants. All the proteins have from 209 to 241 amino acid residues. The enzyme has a TIM barrel structure.
The systematic name of this enzyme class is D-ribulose-5-phosphate 3-epimerase. Other names in common use include phosphoribulose epimerase, erythrose-4-phosphate isomerase, phosphoketopentose 3-epimerase, xylulose phosphate 3-epimerase, phosphoketopentose epimerase, ribulose 5-phosphate 3-epimerase, D-ribulose phosphate-3-epimerase, D-ribulose 5-phosphate epimerase, D-ribulose-5-P 3-epimerase, D-xylulose-5-phosphate 3-epimerase, and pentose-5-phosphate 3-epimerase.
This enzyme participates in 3 metabolic pathways: pentose phosphate pathway, pentose and glucuronate interconversions, and carbon fixation.
Structural studies
As of late 2007, 4 structures have been solved for this class of enzymes, with PDB accession codes 1H1Y, 1H1Z, 1RPX, and 1TQJ.
Human proteins containing this domain
References
- ↑ Bowien B, Kusian B, Yoo JG, Bednarski R (1992). "The Calvin cycle enzyme pentose-5-phosphate 3-epimeras e is encoded within the cfx operons of the chemoautotroph Alcaligenes eutrophus". J. Bacteriol. 174 (22): 7337–7344. PMC 207429. PMID 1429456.
- Ashwell G and Hickman J (1957). "Enzymatic formation of xylulose 5-phosphate from ribose 5-phosphate in spleen". J. Biol. Chem. 226 (1): 65–76. PMID 13428737.
- DICKENS F, WILLIAMSON DH (1956). "Pentose phosphate isomerase and epimerase from animal tissues". Biochem. J. 64 (3): 567–78. PMC 1199776. PMID 13373810.
- Hurwitz J and Horecker BL (1956). "The purification of phosphoketopentoepimerase from Lactobacillus pentosus and the preparation of xylulose 5-phosphate". J. Biol. Chem. 223 (2): 993–1008. PMID 13385247.
- Stumpf PK and Horecker BL (1956). "The roole of xylulose 5-phosphate in xylose metabolism of Lactobacillus pentosus". J. Biol. Chem. 218: 753–768.
- Terada T, Mukae H, Ohashi K, Hosomi S, Mizoguchi T, Uehara K (1985). "Characterization of an enzyme which catalyzes isomerization and epimerization of D-erythrose 4-phosphate". Eur. J. Biochem. 148 (2): 345–51. doi:10.1111/j.1432-1033.1985.tb08845.x. PMID 3987693.