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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/02/02 18:49:03」(JST)

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Tetrapyrroles are a class of chemical compounds whose molecules contain four pyrrole rings held together by direct covalent bonds or by one-carbon bridges (=(CH)- or -CH
2- units), in either a linear or a cyclic fashion. A pyrrole ring in a molecule is a five-atom ring where four of the ring atoms are carbon and one is nitrogen. In cyclic tetrapyrroles, lone electron pairs on nitrogen atoms facing the center of the macrocycle ring can bond or chelate with a metal ion such as iron,cobalt, or magnesium.

Some tetrapyrroles are the active cores of some compounds with crucial biochemical roles in living systems, such as hemoglobin and chlorophyll). In these two molecules, in particular, the pyrrole macrocycle ring frames a metal atom, that forms a coordination compound with the pyrroles and plays a central role in the biochemical function of those molecules.

Structure[edit]

Linear tetrapyrroles (called bilanes) include:^[1]

Heme breakdown products (e.g., bilirubin, biliverdin)
Phycobilins (found in cyanobacteria)


Bilirubin	Biliverdin	Phycoerythrobilin

Cyclic tetrapyrroles having four one-carbon bridges include:^[2]

Porphyrins, including heme, the core of hemoglobin
Chlorins, including those at the core of chlorophyll.

Cyclic tetrapyrroles having three one-carbon bridges and one direct bond between the pyrroles include:

Corrins, including the cores of cobalamins, when complexed with a cobalt ion.


Heme group of hemoglobin	The chlorin section of the chlorophyll a molecule. The green box shows a group that varies between chlorophyll types.	Cobalamin structure includes a corrin macrocycle.

The tetrapyrrole portions of the molecules typically act as chromophores because of a high degree of conjugation in them. Therefore, these compounds are commonly colored.

References[edit]

^ Nomenclature of Tetrapyrroles, Appendix 1. Trivially named porphyrins, chlorins, chlorophylls and bilins, fundamental parents
^ Nomenclature of Tetrapyrroles, Appendix 1. Trivially named porphyrins, chlorins, chlorophylls and bilins, fundamental parents

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2. ビリルビン代謝 bilirubin metabolism
3. ポルフィリン症：概要 porphyrias an overview
4. 急性間欠性ポルフィリン症の病因、臨床症状および診断 pathogenesis clinical manifestations and diagnosis of acute intermittent porphyria

English Journal

Photo-isomerization and oxidation of bilirubin in mammals is dependent on albumin binding.

Goncharova I1, Jašprová J2, Vítek L3, Urbanová M4.
Analytical biochemistry.Anal Biochem.2015 Dec 1;490:34-45. doi: 10.1016/j.ab.2015.08.001. Epub 2015 Aug 19.
The bilirubin (BR) photo-conversion in the human body is a protein-dependent process; an effective photo-isomerization of the potentially neurotoxic Z,Z-BR as well as its oxidation to biliverdin in the antioxidant redox cycle is possible only when BR is bound on serum albumin. We present a novel ana
PMID 26297581

5-Aminolevulinic acid production in engineered Corynebacterium glutamicum via C5 biosynthesis pathway.

Ramzi AB1, Hyeon JE1, Kim SW2, Park C3, Han SO4.
Enzyme and microbial technology.Enzyme Microb Technol.2015 Dec;81:1-7. doi: 10.1016/j.enzmictec.2015.07.004. Epub 2015 Jul 26.
ALA (5-aminolevulinic acid) is an important intermediate in the synthesis of tetrapyrroles and the use of ALA has been gradually increasing in many fields, including medicine and agriculture. In this study, improved biological production of ALA in Corynebacterium glutamicum was achieved by overexpre
PMID 26453466

Mitochondrial translocator protein (TSPO) function is not essential for heme biosynthesis.

Zhao AH1, Tu LN1, Mukai C1, Sirivelu MP2, Pillai VV1, Morohaku K1, Cohen R1, Selvaraj V3.
The Journal of biological chemistry.J Biol Chem.2015 Dec 1. pii: jbc.M115.686360. [Epub ahead of print]
Function of the mammalian translocator protein (TSPO; previously known as the peripheral benzodiazepine receptor/PBR) remains unclear as its presumed role in steroidogenesis and mitochondrial permeability transition established using pharmacological methods have been refuted in recent genetic studie
PMID 26627829