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 Y
ChEMBL	ChEMBL273676 Y
ChemSpider	767 Y
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) Y Key: WDFJYRZCZIUBPR-UHFFFAOYSA-N Y 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.