Uroporphyrinogen I

Uroporphyrinogen I

Names
IUPAC name 3,3′,3′′,3′′′-[3,8,13,18-Tetrakis(carboxymethyl)-10,15,20,22,23,24-hexahydro-5H,21H-porphyrin-2,7,12,17-tetrayl]tetrapropanoic acid
Systematic IUPAC name 3,3′,3′′,3′′′-[1^4,3^3,5^3,7^3-Tetrakis(carboxymethyl)-1^1H,3^1H,5^1H,7^1H-1,3,5,7(2,5)-tetrapyrrolacyclooctaphane-1^3,3^4,5^4,7^4-tetrayl]tetrapropanoic acid
Identifiers
CAS Number	1867-62-5^Y
3D model (JSmol)	Interactive image
ChemSpider	389644^N
PubChem CID	440775
CompTox Dashboard (EPA)	DTXSID401046768
InChI InChI=1S/C40H44N4O16/c45-33(46)5-1-17-21(9-37(53)54)29-14-26-19(3-7-35(49)50)23(11-39(57)58)31(43-26)16-28-20(4-8-36(51)52)24(12-40(59)60)32(44-28)15-27-18(2-6-34(47)48)22(10-38(55)56)30(42-27)13-25(17)41-29/h41-44H,1-16H2,(H,45,46)(H,47,48)(H,49,50)(H,51,52)(H,53,54)(H,55,56)(H,57,58)(H,59,60)^N Key: QTTNOSKSLATGQB-UHFFFAOYSA-N^N InChI=1/C40H44N4O16/c45-33(46)5-1-17-21(9-37(53)54)29-14-26-19(3-7-35(49)50)23(11-39(57)58)31(43-26)16-28-20(4-8-36(51)52)24(12-40(59)60)32(44-28)15-27-18(2-6-34(47)48)22(10-38(55)56)30(42-27)13-25(17)41-29/h41-44H,1-16H2,(H,45,46)(H,47,48)(H,49,50)(H,51,52)(H,53,54)(H,55,56)(H,57,58)(H,59,60) Key: QTTNOSKSLATGQB-UHFFFAOYAX
SMILES O=C(O)CCc1c(c5[nH]c1Cc2[nH]c(c(c2CC(=O)O)CCC(=O)O)Cc3c(c(c([nH]3)Cc4c(c(c([nH]4)C5)CCC(=O)O)CC(=O)O)CCC(=O)O)CC(=O)O)CC(=O)O
Properties
Chemical formula	C40H44N4O16
Molar mass	836.804 g·mol^−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is ^YN ?) Infobox references

Uroporphyrinogen I is an isomer of uroporphyrinogen III, a metabolic intermediate in the biosynthesis of heme. A type of porphyria is caused by production of uroporphyrinogen I instead of III.

Biosynthesis and metabolism

In living organisms, uroporphyrinogen I occurs as a side branch of the main porphyrin synthesis pathway. In the normal pathway, the linear tetrapyrrole precursor preuroporphyrinogen (a substituted hydroxymethylbilane) is converted by the enzyme uroporphyrinogen-III cosynthase into the cyclic uroporphyrinogen III; which is then converted to coproporphyrinogen III on the way to porphyrins like heme. Uroporphyrinogen I is instead produced spontaneously from preuroporphyrinogen when the enzyme is not present.[1][2]

Uroporphyrinogen I synthesis from preuroporphyrinogen

The difference between the I and III forms is the arrangement of the four carboxyethyl groups (propionic acid, "P") and the four carboxymethyl groups (acetic acid, "A"). The non-enzymatic conversion to uroporphyrinogen I results in the sequence AP-AP-AP-AP, whereas the enzymatic conversion into uroporphyrinogen III leads to reversal of one AP-group and hence an AP-AP-AP-PA arrangement.

If synthesized, uroporphyrinogen I is then converted into coproporphyrinogen I by the same enzyme (uroporphyrinogen decarboxylase) that acts on the III form; but that product, which is cytotoxic, then accumulates causing the pathology congenital erythropoietic porphyria.[2][3]

References

1. Paul R. Ortiz de Montellano (2008). "Hemes in Biology". Wiley Encyclopedia of Chemical Biology. John Wiley & Sons. pp. 1–10. doi:10.1002/9780470048672.wecb221. ISBN 978-0470048672.
2. Sassa, S.; Kappas, A. (2000). "Molecular aspects of the inherited porphyrias". Journal of Internal Medicine. 247 (2): 169–178. doi:10.1046/j.1365-2796.2000.00618.x. PMID 10692079. S2CID 36820694.
3. Di Pierro, Elena; Brancaleoni, Valentina; Granata, Francesca (2016). "Advances in understanding the pathogenesis of congenital erythropoietic porphyria". British Journal of Haematology. 173 (3): 365–379. doi:10.1111/bjh.13978. PMID 26969896. S2CID 46873299.