Coproporphyrinogen III

Coproporphyrinogen III is a metabolic intermediate in the biosynthesis of many compounds that are critical for living organisms, such as hemoglobin and chlorophyll. It is a colorless solid.

Coproporphyrinogen III

Names
IUPAC name 3-[8,12,17-tris(2-carboxyethyl)-3,7,13,18-tetramethyl-5,10,15,20,21,22, 23,24-octahydroporphyrin-2-yl]propanoic acid
Identifiers
CAS Number	2624-63-7 Y
3D model (JSmol)	Interactive image
ChemSpider	315 Y
MeSH	Coproporphyrinogen+III
PubChem CID	321
CompTox Dashboard (EPA)	DTXSID40180875
InChI InChI=1S/C36H44N4O8/c1-17-21(5-9-33(41)42)29-14-27-19(3)22(6-10-34(43)44)30(39-27)15-28-20(4)24(8-12-36(47)48)32(40-28)16-31-23(7-11-35(45)46)18(2)26(38-31)13-25(17)37-29/h37-40H,5-16H2,1-4H3,(H,41,42)(H,43,44)(H,45,46)(H,47,48) N Key: NIUVHXTXUXOFEB-UHFFFAOYSA-N Y InChI=1/C36H44N4O8/c1-17-21(5-9-33(41)42)29-14-27-19(3)22(6-10-34(43)44)30(39-27)15-28-20(4)24(8-12-36(47)48)32(40-28)16-31-23(7-11-35(45)46)18(2)26(38-31)13-25(17)37-29/h37-40H,5-16H2,1-4H3,(H,41,42)(H,43,44)(H,45,46)(H,47,48) Key: NIUVHXTXUXOFEB-UHFFFAOYAI
SMILES Cc1c2[nH]c(c1CCC(=O)O)Cc3c(c(c([nH]3)Cc4c(c(c([nH]4)Cc5c(c(c([nH]5)C2)C)CCC(=O)O)CCC(=O)O)C)CCC(=O)O)C
Properties
Chemical formula	C36H44N4O8 protonated carboxylic acids
Molar mass	660.757 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

The compound is a porphyrinogen, a class of compounds characterized by a hexahydroporphine core with various side chains. The coproporphyrinogens have the outermost hydrogen atoms of the core replaced by four methyl groups −CH₃ (M) and four propionic acid groups −CH₂−CH₂−COOH (P). In coproporphyrogen III, the order around the outer ring is MP-MP-MP-PM. For comparison, coproporphyrinogen I has them in the sequence MP-MP-MP-MP. heme.

Biosynthesis and metabolism

In the main porphyrin biosynthesis pathway, coproporphyrinogen III is derived from uroporphyrinogen III by the action of the enzyme uroporphyrinogen III decarboxylase:

The conversion entails four decarboxylations, which turn the four acetic acid groups −CH₂−COOH into methyl groups −CH₃, with release of four carbon dioxide molecules.^[1][2]

Coproporphyrinogen III is further used as a substrate for the enzyme coproporphyrinogen III oxidase which oxidizes and further decarboxylates it to protoporphyrinogen IX.