Hydroxymethylbilane

Hydroxymethylbilane, also known as preuroporphyrinogen, is an organic compound that occurs in living organisms during the synthesis of porphyrins, a group of critical substances that include haemoglobin, myoglobin, and chlorophyll. The name is often abbreviated as HMB.

Hydroxymethylbilane

Identifiers
3D model (JSmol)	Interactive image
ChEBI	CHEBI:16645
ChEMBL	ChEMBL273676
ChemSpider	767
MeSH	hydroxymethylbilane
PubChem CID	788
InChI InChI=1S/C40H46N4O17/c45-17-32-25(12-40(60)61)21(4-8-36(52)53)29(44-32)15-31-24(11-39(58)59)20(3-7-35(50)51)28(43-31)14-30-23(10-38(56)57)19(2-6-34(48)49)27(42-30)13-26-22(9-37(54)55)18(16-41-26)1-5-33(46)47/h16,41-45H,1-15,17H2,(H,46,47)(H,48,49)(H,50,51)(H,52,53)(H,54,55)(H,56,57)(H,58,59)(H,60,61) Key: WDFJYRZCZIUBPR-UHFFFAOYSA-N InChI=1/C40H46N4O17/c45-17-32-25(12-40(60)61)21(4-8-36(52)53)29(44-32)15-31-24(11-39(58)59)20(3-7-35(50)51)28(43-31)14-30-23(10-38(56)57)19(2-6-34(48)49)27(42-30)13-26-22(9-37(54)55)18(16-41-26)1-5-33(46)47/h16,41-45H,1-15,17H2,(H,46,47)(H,48,49)(H,50,51)(H,52,53)(H,54,55)(H,56,57)(H,58,59)(H,60,61) Key: WDFJYRZCZIUBPR-UHFFFAOYAI
SMILES O=C(O)Cc1c(c[nH]c1Cc2c(c(c([nH]2)Cc3[nH]c(c(c3CCC(=O)O)CC(=O)O)Cc4c(c(c([nH]4)CO)CC(=O)O)CCC(=O)O)CC(=O)O)CCC(=O)O)CCC(=O)O
Properties
Chemical formula	C40H46N4O17
Molar mass	854.81 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

The compound is a substituted bilane, a chain of four pyrrole rings interconnected by methylene bridges −CH
2−. The chain starts with a hydroxymethyl group −CH
2−OH and ends with an hydrogen, in place of the respective methylene bridges. The other two carbon atoms of each pyrrole cycle are connected to an acetic acid group −CH
2−COOH and a propionic acid group −CH
2−CH
2−COOH, in that order. [1]

The compound is generated from four molecules of porphobilinogen by the enzyme porphobilinogen deaminase:

The enzyme uroporphyrinogen III synthase closes the chain to form a porphyrinogen a class of compounds with the hexahydroporphine macrocycle; specifically, uroporphyrinogen III. In the absence of the enzyme, the compound undergoes spontaneous cyclization and becomes uroporphyrinogen I.

References

1. Paul R. Ortiz de Montellano (2008). "Hemes in Biology". Wiley Encyclopedia of Chemical Biology. John Wiley & Sons. doi:10.1002/9780470048672.wecb221. ISBN 978-0470048672.