Protoporphyrins are tetrapyrroles containing the following side chains:
- methyl (4)
- propionic acid (2)
- vinyl (2)
Protoporphyrin IX is a biochemically widely used carrier molecule for divalent cations. Together with iron (Fe 2+) the body of the heme- group of hemoglobin, myoglobin and many other heme-containing enzymes like cytochrome c and catalase are formed. Complexed with magnesium-ions (Mg 2+) the main part of the Chlorophylls are formed. Complexed with zinc-ions (Zn 2+) it forms Zinc protoporphyrin.
The number (e.g. IX) indicates the position of different side chains, but historically, as the nomenclature has grown, it has done so systematically only in parts.
Protoporphyrin IX as a direct precursor of heme is accumulated by patients of erythropoietic protoporphyria, which is one of the genetic disorders of the biosynthesis of the heme -pathway. It causes a severe photosensivity against visible light.
The sensitivity of protoporphyrin IX against light is also used as a therapy against different forms of cancer (photodynamic therapy, PDT).
Protoporphyrins are deposited in the shells of the eggs of some birds as a brown or red pigment, either as a ground colour or as spotting. This occurs in most passerine species, some ground-nesting non-passerines, such as waders, gulls, nightjars and sandgrouse, where it provides camouflage, and some parasitic cuckoos, which need to mimic their passerine hosts' eggs.
Protoporphyrins strengthen the egg shell, and are deposited where the shell is too thin as a result of calcium shortage. Spotting therefore tend to be heavier where the local soil is calcium-deficient, and in the eggs laid last in a clutch.
Other articles related to "protoporphyrin, protoporphyrins":
... Methyl aminolevulinate Protoporphyrin for other roles of protoporphyrin IX Types of tetrapyrroles Bilanes (Linear) Bilirubin Biliverdin Stercobilinogen ...
... Macrocycle Corrinoids Methylcobalamin Adenosylcobalamin Cyanocobalamin Porphyrins Protoporphyrins Protoporphyrin IX Heme (b, c, a, o) Zinc protoporphyrin Magnesium protoporphyrin ...
... is an enzyme that catalyses the terminal (eighth) step in the biosynthesis of heme, converting protoporphyrin IX into heme ... It catalyses the reaction protoporphyrin + Fe++ ↔ protoheme + 2 H+ ... localized to the mitochondrion where it catalyzes the insertion of the ferrous form of iron into protoporphyrin IX in the heme synthesis pathway ...
... catalyses the insertion of Mg2+ into protoporphyrin IX ... suitable for photosynthetic growth ATP + protoporphyrin IX + Mg2+ + H2O ADP + phosphate + Mg-protoporphyrin IX + 2 H+ The 4 substrates of this enzyme ... The systematic name of this enzyme class is Mg-protoporphyrin IX magnesium-lyase ...