Porphyrin

From Wikipedia, the free encyclopedia
(Redirected from ClFeTPP)
Jump to navigation Jump to search

Template:Short description Script error: No such module "Distinguish".

File:Porphyrin.svg
Porphine, the parent of porphyrin

Template:Use dmy dates

Porphyrins (Template:IPAc-en Template:Respell) are heterocyclic, macrocyclic, organic compounds, composed of four modified pyrrole subunits interconnected at their α carbon atoms via methine bridges (Template:Chem2). In vertebrates, an essential member of the porphyrin group is heme, which is a component of hemoproteins, whose functions include carrying oxygen in the bloodstream. In plants, an essential porphyrin derivative is chlorophyll, which is involved in light harvesting and electron transfer in photosynthesis.

The parent of porphyrins is porphine, a rare chemical compound of exclusively theoretical interest. Substituted porphines are called porphyrins.[1] With a total of 26 π-electrons the porphyrin ring structure is a coordinated aromatic system.[2] One result of the large conjugated system is that porphyrins absorb strongly in the visible region of the electromagnetic spectrum, i.e. they are deeply colored. The name "porphyrin" derives Template:Ety.[3]

Structure

Porphyrin complexes consist of a square planar MN4 core. The periphery of the porphyrins, consisting of sp2-hybridized carbons, generally display small deviations from planarity. "Ruffled" or saddle-shaped porphyrins is attributed to interactions of the system with its environment.[4] Additionally, the metal is often not centered in the N4 plane.[5] For free porphyrins, the two pyrrole protons are mutually trans and project out of the N4 plane.[6] These nonplanar distortions are associated with altered chemical and physical properties. Chlorophyll-rings are more distinctly nonplanar, but they are more saturated than porphyrins.[7]

Complexes of porphyrins

Script error: No such module "Labelled list hatnote". Concomitant with the displacement of two N-H protons, porphyrins bind metal ions in the N4 "pocket". The metal ion usually has a charge of 2+ or 3+. A schematic equation for these syntheses is shown, where M = metal ion and L = a ligand:

Template:Chem2


Ancient porphyrins

A geoporphyrin, also known as a petroporphyrin, is a porphyrin of geologic origin.[8] They can occur in crude oil, oil shale, coal, or sedimentary rocks.[8][9] Abelsonite is possibly the only geoporphyrin mineral, as it is rare for porphyrins to occur in isolation and form crystals.[10]

The field of organic geochemistry had its origins in the isolation of porphyrins from petroleum. These findings helped establish the biological origins of petroleum.[11][12] Petroleum is sometimes "fingerprinted" by analysis of trace amounts of nickel and vanadyl porphyrins. Metalloporphyrins in general are highly stable organic compounds, and the detailed structures of the extracted derivatives made clear that they originated from chlorophyll.

Biosynthesis

In non-photosynthetic eukaryotes such as animals, insects, fungi, and protozoa, as well as the α-proteobacteria group of bacteria, the committed step for porphyrin biosynthesis is the formation of δ-aminolevulinic acid (δ-ALA, 5-ALA or dALA) by the reaction of the amino acid glycine with succinyl-CoA from the citric acid cycle. In plants, algae, bacteria (except for the α-proteobacteria group) and archaea, it is produced from glutamic acid via glutamyl-tRNA and glutamate-1-semialdehyde. The enzymes involved in this pathway are glutamyl-tRNA synthetase, glutamyl-tRNA reductase, and glutamate-1-semialdehyde 2,1-aminomutase. This pathway is known as the C5 or Beale pathway.

Two molecules of dALA are then combined by porphobilinogen synthase to give porphobilinogen (PBG), which contains a pyrrole ring. Four PBGs are then combined through deamination into hydroxymethyl bilane (HMB), which is hydrolysed to form the circular tetrapyrrole uroporphyrinogen III. This molecule undergoes a number of further modifications. Intermediates are used in different species to form particular substances, but, in humans, the main end-product protoporphyrin IX is combined with iron to form heme. Bile pigments are the breakdown products of heme.

The following scheme summarizes the biosynthesis of porphyrins, with references by EC number and the OMIM database. The porphyria associated with the deficiency of each enzyme is also shown:

File:Heme-Synthesis-Chemical-Details-Mirror.svg
Heme B biosynthesis pathway and its modulators. Major enzyme deficiences are also shown.
Enzyme Location Substrate Product Chromosome EC OMIM Disorder
ALA synthase Mitochondrion Glycine, succinyl CoA δ-Aminolevulinic acid 3p21.1 2.3.1.37 125290 X-linked dominant protoporphyria, X-linked sideroblastic anemia
ALA dehydratase Cytosol δ-Aminolevulinic acid Porphobilinogen 9q34 4.2.1.24 125270 aminolevulinic acid dehydratase deficiency porphyria
PBG deaminase Cytosol Porphobilinogen Hydroxymethyl bilane 11q23.3 2.5.1.61 176000 acute intermittent porphyria
Uroporphyrinogen III synthase Cytosol Hydroxymethyl bilane Uroporphyrinogen III 10q25.2-q26.3 4.2.1.75 606938 congenital erythropoietic porphyria
Uroporphyrinogen III decarboxylase Cytosol Uroporphyrinogen III Coproporphyrinogen III 1p34 4.1.1.37 176100 porphyria cutanea tarda, hepatoerythropoietic porphyria
Coproporphyrinogen III oxidase Mitochondrion Coproporphyrinogen III Protoporphyrinogen IX 3q12 1.3.3.3 121300 hereditary coproporphyria
Protoporphyrinogen oxidase Mitochondrion Protoporphyrinogen IX Protoporphyrin IX 1q22 1.3.3.4 600923 variegate porphyria
Ferrochelatase Mitochondrion Protoporphyrin IX Heme 18q21.3 4.99.1.1 177000 erythropoietic protoporphyria

Laboratory synthesis

Script error: No such module "Labelled list hatnote".

File:Tetratolylporphyrin.jpg
Brilliant crystals of meso-tetratolylporphyrin, prepared from 4-methylbenzaldehyde and pyrrole in refluxing propionic acid

A common synthesis for porphyrins is the Rothemund reaction, first reported in 1936,[13][14] which is also the basis for more recent methods described by Adler and Longo.[15] The general scheme is a condensation and oxidation process starting with pyrrole and an aldehyde.

File:H2TPPsyn.png

Potential applications

Photodynamic therapy

Porphyrins have been evaluated in the context of photodynamic therapy (PDT) since they strongly absorb light, which is then converted to heat in the illuminated areas.[16] This technique has been applied in macular degeneration using verteporfin.[17]

PDT is considered a noninvasive cancer treatment, involving the interaction between light of a determined frequency, a photo-sensitizer, and oxygen. This interaction produces the formation of a highly reactive oxygen species (ROS), usually singlet oxygen, as well as superoxide anion, free hydroxyl radical, or hydrogen peroxide.[18] These high reactive oxygen species react with susceptible cellular organic biomolecules such as; lipids, aromatic amino acids, and nucleic acid heterocyclic bases, to produce oxidative radicals that damage the cell, possibly inducing apoptosis or even necrosis.[19]

Molecular electronics and sensors

Porphyrin-based compounds are of interest as possible components of molecular electronics and photonics.[20] Synthetic porphyrin dyes have been incorporated in prototype dye-sensitized solar cells.[21][22]

Biological applications

Porphyrins have been investigated as possible anti-inflammatory agents[23] and evaluated on their anti-cancer and anti-oxidant activity.[24] Several porphyrin-peptide conjugates were found to have antiviral activity against HIV in vitro.[25]

Toxicology

Heme biosynthesis is used as biomarker in environmental toxicology studies. While excess production of porphyrins indicate organochlorine exposure, lead inhibits ALA dehydratase enzyme.[26]

Gallery

Related species

In nature

Several heterocycles related to porphyrins are found in nature, almost always bound to metal ions. These include

N4-macrocycle Cofactor name metal comment
chlorin chlorophyll magnesium several versions of chlorophyll exist (sidechain; exception being chlorophyll c)
bacteriochlorin bacteriochlorophyll (in part) magnesium several versions of bacteriochlorophyll exist (sidechain; some use a usual chlorin ring)
sirohydrochlorin (an isobacteriochlorin) siroheme iron Important cofactor in sulfur assimilation
biosynthetic intermediate en route to cofactor F430 and B12
corrin vitamin B12 cobalt several variants of B12 exist (sidechain)
corphin Cofactor F430 nickel highly reduced macrocycle

Synthetic

A benzoporphyrin is a porphyrin with a benzene ring fused to one of the pyrrole units. e.g. verteporfin is a benzoporphyrin derivative.[27]

Non-natural porphyrin isomers

File:First Porphycene synthesis.tif
Porphycene, first porphyrin isomer, synthesised from bipyrrole dialdehyde through McMurry coupling reaction

The first synthetic porphyrin isomer was reported by Emanual Vogel and coworkers in 1986.[28] This isomer [18]porphyrin-(2.0.2.0) is named as porphycene, and the central N4 Cavity forms a rectangle shape as shown in figure.[29] Porphycenes showed interesting photophysical behavior and found versatile compound towards the photodynamic therapy.[30] This result was followed by the preparation of [18]porphyrin-(2.1.0.1), named it as corrphycene or porphycerin.[31] Other non-natural porphyrins include [18]porphyrin-(2.1.1.0) and [18]porphyrin-(3.0.1.0) or isoporphycene.[32] The N-confused porphyrins feature one of the pyrrolic subunits with the nitrogen atoms facing outwards from the core of the macrocycle.[33][34]

File:Isomers of porphyrins soman.jpg
Various reported Isomers of porphyrin

See also

References

<templatestyles src="Reflist/styles.css" />

  1. ↑ Script error: No such module "Citation/CS1".
  2. ↑ Script error: No such module "Citation/CS1".
  3. ↑ Script error: No such module "citation/CS1".
  4. ↑ Script error: No such module "Citation/CS1".
  5. ↑ Script error: No such module "citation/CS1".
  6. ↑ Script error: No such module "Citation/CS1".
  7. ↑ Script error: No such module "Citation/CS1".
  8. ↑ a b Script error: No such module "citation/CS1".
  9. ↑ Script error: No such module "Citation/CS1".
  10. ↑ Script error: No such module "Citation/CS1".
  11. ↑ Kvenvolden, Keith A. (2006). "Organic geochemistry – A retrospective of its first 70 years". Organic Geochemistry. 37: 1–11. doi:10.1016/j.orggeochem.2005.09.001
  12. ↑ Treibs, A.E. (1936). "Chlorophyll- und Häminderivate in organischen Mineralstoffen". Angewandte Chemie. 49: 682–686. doi:10.1002/ange.19360493803
  13. ↑ Script error: No such module "Citation/CS1".
  14. ↑ Script error: No such module "Citation/CS1".
  15. ↑ Script error: No such module "Citation/CS1".
  16. ↑ Script error: No such module "citation/CS1".
  17. ↑ Script error: No such module "Citation/CS1".
  18. ↑ Script error: No such module "Citation/CS1".
  19. ↑ Script error: No such module "Citation/CS1".
  20. ↑ Script error: No such module "Citation/CS1".
  21. ↑ Script error: No such module "Citation/CS1".
  22. ↑ Script error: No such module "Citation/CS1".
  23. ↑ Script error: No such module "Citation/CS1".
  24. ↑ Script error: No such module "Citation/CS1".
  25. ↑ Script error: No such module "Citation/CS1".
  26. ↑ Script error: No such module "citation/CS1".
  27. ↑ Script error: No such module "Citation/CS1".
  28. ↑ Script error: No such module "Citation/CS1".
  29. ↑ Script error: No such module "Citation/CS1".
  30. ↑ Script error: No such module "Citation/CS1".
  31. ↑ Script error: No such module "Citation/CS1".
  32. ↑ Script error: No such module "Citation/CS1".
  33. ↑ Script error: No such module "Citation/CS1".
  34. ↑ Script error: No such module "Citation/CS1".

Script error: No such module "Check for unknown parameters".

External links

Template:Sister project

Script error: No such module "Navbox". Template:Authority control

Retrieved from "http://debianws.lexgopc.com/wiki143/index.php?title=Porphyrin&oldid=3442910"