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discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
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MetaCyc Enzyme: phytoene desaturase

Gene: crtI Accession Number: G-11381 (MetaCyc)

Species: Rhodobacter capsulatus

Summary:
phytoene desaturase catalyzes the desaturation of all-trans-phytoene to all-trans neurosporene in three steps.

The crtI gene from Rhodobacter capsulatus was found to be responsible for this activity [Giuliano86]. The gene was cloned and expressed in Escherichia coli, and the resulting protein was purified [Raisig96]. The enzyme converted all-trans-phytoene, as well as the intermediates all-trans phytofluene and all-trans-ζ-carotene, to all-trans neurosporene, the end product of the reaction.

1,2-epoxy phytoene was also a suitable substrate.

Gene Citations: [Bartley89]

Molecular Weight of Polypeptide: 57.978 kD (from nucleotide sequence), 57.0 kD (experimental) [Raisig96 ]

Unification Links: Entrez-Nucleotide:J04969 , Protein Model Portal:P17054 , UniProt:P17054

Relationship Links: InterPro:IN-FAMILY:IPR002937 , InterPro:IN-FAMILY:IPR008150 , InterPro:IN-FAMILY:IPR014105 , Panther:IN-FAMILY:PTHR10668:SF3 , Pfam:IN-FAMILY:PF01593 , Prosite:IN-FAMILY:PS00982

Gene-Reaction Schematic: ?

Credits:
Created 25-Jun-2009 by Caspi R , SRI International


Enzymatic reaction of: phytoene desaturase (neurosporene-forming)

EC Number: 1.3.99.28

15-cis-phytoene + 3 an oxidized electron acceptor <=> all-trans neurosporene + 3 a reduced electron acceptor

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

Reversibility of this reaction is unspecified.

In Pathways: neurosporene biosynthesis


Enzymatic reaction of: ζ-carotene desaturase (phytoene desaturase)

all-trans-ζ-carotene + an oxidized electron acceptor <=> all-trans neurosporene + a reduced electron acceptor

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is favored in the direction shown.

In Pathways: neurosporene biosynthesis

Cofactors or Prosthetic Groups: FAD [Raisig96]

Inhibitors (Unknown Mechanism): diphenylamine [Raisig96]

Kinetic Parameters:

Substrate
Km (μM)
Citations
all-trans-ζ-carotene
16.6
[Raisig96]


Enzymatic reaction of: phytofluene desaturase (phytoene desaturase)

all-trans phytofluene + an oxidized electron acceptor <=> all-trans-ζ-carotene + a reduced electron acceptor

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is favored in the direction shown.

In Pathways: neurosporene biosynthesis

Cofactors or Prosthetic Groups: FAD [Raisig96]

Inhibitors (Unknown Mechanism): diphenylamine [Raisig96]


Enzymatic reaction of: phytoene desaturase

15-cis-phytoene + an oxidized electron acceptor <=> all-trans phytofluene + a reduced electron acceptor

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is favored in the direction shown.

In Pathways: neurosporene biosynthesis

Cofactors or Prosthetic Groups: FAD [Raisig96]

Inhibitors (Unknown Mechanism): diphenylamine [Raisig96]


References

Bartley89: Bartley GE, Scolnik PA (1989). "Carotenoid biosynthesis in photosynthetic bacteria. Genetic characterization of the Rhodobacter capsulatus CrtI protein." J Biol Chem 264(22);13109-13. PMID: 2546948

Giuliano86: Giuliano G, Pollock D, Scolnik PA (1986). "The gene crtI mediates the conversion of phytoene into colored carotenoids in Rhodopseudomonas capsulata." J Biol Chem 261(28);12925-9. PMID: 3020015

Raisig96: Raisig A, Bartley G, Scolnik P, Sandmann G (1996). "Purification in an active state and properties of the 3-step phytoene desaturase from Rhodobacter capsulatus overexpressed in Escherichia coli." J Biochem 119(3);559-64. PMID: 8830054


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 18.5 on Fri Nov 21, 2014, BIOCYC14A.