Pheophorbide

Pheophorbide a
Names
IUPAC name
(3S,4S)-9-Ethenyl-14-ethyl-21-(methoxycarbonyl)-4,8,13,18-tetramethyl-20-oxo-3-phorbinepropanoic acid
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.036.110 Edit this at Wikidata
EC Number
  • 239-738-5
KEGG
UNII
  • InChI=1S/C35H36N4O5/c1-8-19-15(3)22-12-24-17(5)21(10-11-28(40)41)32(38-24)30-31(35(43)44-7)34(42)29-18(6)25(39-33(29)30)14-27-20(9-2)16(4)23(37-27)13-26(19)36-22/h8,12-14,17,21,31,36,39H,1,9-11H2,2-7H3,(H,40,41)/b22-12-,23-13-,24-12-,25-14-,26-13-,27-14-,32-30-/t17-,21-,31+/m0/s1
    Key: NSFSLUUZQIAOOX-QEWKCGBTSA-N
  • CCC1=C2C=C3C(=C4C(=O)[C@@H](C(=C5[C@H]([C@@H](C(=N5)C=C6C(=C(C(=CC(=C1C)N2)N6)C=C)C)C)CCC(=O)O)C4=N3)C(=O)OC)C
Properties
C35H36N4O5
Molar mass 592.68 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Pheophorbide or phaeophorbide is a product of chlorophyll breakdown and a derivative of pheophytin where both the central magnesium has been removed and the phytol tail has been hydrolyzed. It is used as a photosensitizer in photodynamic therapy.

Pheophorbide may be generated by digestion of ingested plant matter. Both worm (Caenorhabditis elegans) and mouse mitochondria are able to use the molecule in a form of ad hoc photoheterotrophy.

In chlorophyll a metabolism

Pheophorbide is a product of chlorophyll breakdown and a derivative of pheophytin where both the central magnesium ion has been removed and the phytol tail has been hydrolyzed as plants senesce.

2D representation of the chemical structure of chlorophyll a.
chlorophyll a
Two steps
 
 
Rightward reaction arrow
 
 
 
2D representation of the chemical structure of pheophorbide .
pheophorbide

Further reactions within the enzymes pheophorbide a oxygenase and red chlorophyll catabolite reductase convert pheophorbide via a red catabolite into a fluorescent final product. The oxygenase is a Rieske protein containing an iron–sulfur cluster that requires reduced ferredoxin to function. The reductase also requires ferredoxin.

pheophorbide
 
Oxygenase
 
 
Rightward reaction arrow
 
 
 
2D representation of the chemical structure of Q27120845.
red chlorophyll catabolite
Reductase
 
 
Rightward reaction arrow
 
 
 
2D representation of the chemical structure of Q27120875.
primary fluorescent
chlorophyll catabolite

The fluorescent product can exist in two diastereomeric forms. All plants in a given genera produce a single isomer.

An alternative breakdown pathway for pheophorbide involves the action of pheophorbidase. This enzyme hydrolyses the methyl ester, giving an acid which spontaneously decarboxylates to pyropheophorbide a:

pheophorbide + H2O
 
 
 
CH3OH + CO2
Rightward reaction arrow with minor product(s) to top right
 
 
 
2D representation of the chemical structure of Q27121183.
pyropheophorbide a

See also

References

  1. 1 2 Chen, Kuan; Preuß, Annegret; Hackbarth, Steffen; Wacker, Matthias; Langer, Klaus; Röder, Beate (2009). "Novel photosensitizer-protein nanoparticles for Photodynamic therapy: Photophysical characterization and in vitro investigations". Journal of Photochemistry and Photobiology B: Biology. 96 (1): 66–74. doi:10.1016/j.jphotobiol.2009.04.006. PMID 19442534.
  2. ↑ Xu, Chen; Zhang, Junhua; Mihai, Doina M.; Washington, Ilyas (2014-01-15). "Light-harvesting chlorophyll pigments enable mammalian mitochondria to capture photonic energy and produce ATP". Journal of Cell Science. 127 (2): 388–399. doi:10.1242/jcs.134262. ISSN 0021-9533. PMC 6518289. PMID 24198392.
  3. ↑ Ougham, H.; Hörtensteiner, S.; Armstead, I.; Donnison, I.; King, I.; Thomas, H.; Mur, L. (2008). "The control of chlorophyll catabolism and the status of yellowing as a biomarker of leaf senescence". Plant Biology. 10: 4–14. doi:10.1111/j.1438-8677.2008.00081.x. PMID 18721307.
  4. 1 2 Pružinská, Adriana; Anders, Iwona; Aubry, Sylvain; Schenk, Nicole; Tapernoux-Lüthi, Esther; Müller, Thomas; Kräutler, Bernhard; Hörtensteiner, Stefan (2007). "In Vivo Participation of Red Chlorophyll Catabolite Reductase in Chlorophyll Breakdown". The Plant Cell. 19 (1): 369–387. doi:10.1105/tpc.106.044404. PMC 1820978. PMID 17237353.
  5. ↑ Pružinská, Adriana; Tanner, Gaby; Anders, Iwona; Roca, Maria; Hörtensteiner, Stefan (2003). "Chlorophyll breakdown: Pheophorbide a oxygenase is a Rieske-type iron–sulfur protein, encoded by the accelerated cell death 1 gene". Proceedings of the National Academy of Sciences. 100 (25): 15259–15264. doi:10.1073/pnas.2036571100. PMC 299977. PMID 14657372.
  6. ↑ Enzyme 1.3.7.12 at KEGG Pathway Database.
  7. ↑ Wüthrich, Karin L.; Bovet, Lucien; Hunziker, Peter E.; Donnison, Iain S.; Hörtensteiner, Stefan (2000). "Molecular cloning, functional expression and characterisation of RCC reductase involved in chlorophyll catabolism". The Plant Journal. 21 (2): 189–198. doi:10.1046/j.1365-313x.2000.00667.x. PMID 10743659.
  8. 1 2 Hörtensteiner, S. (2006). "Chlorophyll Degradation During Senescence". Annual Review of Plant Biology. 57: 55–77. doi:10.1146/annurev.arplant.57.032905.105212. PMID 16669755.
  9. ↑ Suzuki, Yasuyo; Amano, Toyoki; Shioi, Yuzo (2006). "Characterization and Cloning of the Chlorophyll-Degrading Enzyme Pheophorbidase from Cotyledons of Radish". Plant Physiology. 140 (2): 716–725. doi:10.1104/pp.105.071290. PMC 1361337. PMID 16384908.