Tetrapyrroles and related compounds

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cobalamines: See corrinoids.

corrinoids (cobalamines, corphyrins, corrins, vitamin B12 compounds):

Derivatives of the corrin nucleus, which contains four reduced or partly reduced pyrrole rings joined in a macrocycle by three =CH- groups and one direct carbon-carbon bond linking alpha positions. BNRD Nomenclature of Corrinoids (p. 272).



Compounds containing two pyrrole rings linked through a methine, -CH=, group. BNRD Rule TP-7.2 (p. 310).

dipyrromethenes: See pyrromethenes.

haems: An alternative spelling for hemes.

hemes and heme derivatives:*

Complexes consisting of an iron ion coordinated to a porphyrin acting as a tetradentate ligand, and to one or two axial ligands. BNRD, Rules TP-8.1, TP-8.4.3 (p. 311, 316).


Chloro(porphyrinato)iron(III) complexes. See also hemes and heme derivatives. BNRD, Rule TP-8.4.3 (p. 316).


Iron-porphyrin complexes, having one or two basic ligands (e.g. piperidine, amines). See also hemes and heme derivatives. BNRD, Rule TP-8.4.3 (p. 316).


Heme derivatives having a protein chain as axial ligand.


Natural pigments containing a fundamental skeleton of four pyrrole nuclei united through the [alpha]-positions by four methine groups to form a macrocyclic structure (porphyrin is designated porphine in Chemical Abstracts indexes). See also corrinoids. BNRD, The Nomenclature of Tetrapyrroles, Rule TP-1.1 (p. 281).



A less preferred term for dipyrrins. (The term 'pyrromethane' has been used for the system with a -CH2- linkage.) See dipyrrins.


Natural pigments containing four pyrrole rings joined by one-carbon units linking position 2 of one pyrrole ring to position 5 of the next. Porphyrins are macrocyclic tetrapyrroles. BNRD, Nomenclature of tetrapyrroles, introduction (p. 279). E.g. bilin (a linear tetrapyrrole)

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