Uroporphyrinogen decarboxylase, also known as UROD, is a human gene.^[1]

Uroporphyrinogen III decarboxylase (UroD) is a homodimeric enzyme (, ) which catalyzes the fifth step in heme biosynthesis: the elimination of carboxyl groups from the four acetate side chains of uroporphyrinogen III to yield coproporphyrinogen III.

At low substrate concentrations the reaction is believed to follow an ordered route, with the sequential removal of CO₂ from the D, A, B, and C rings, whereas at higher substrate/enzyme levels a random route seems to be operative. The enzyme functions as a dimer in solution, and both the enzymes from human and tobacco have been crystallized and solved at good resolutions.

The reaction catalyzed by UroD

Proposed reaction mechanism of uroporphyrinogen III decarboxyklase

Silva & Ramos (2005) performed a detailed study of competing reaction mechanisms proposed for uroporphyrinogen decarboxylase.^[2]

References

Further reading

Heme synthesis—note that some reactions occur in the cytoplasm and some in the mitochondrion (yellow)

References

1. ↑
2. ↑ Silva PJ, Ramos MJ. Density-functional study of mechanisms for the cofactor-free decarboxylation performed by uroporphyrinogen III decarboxylase. J Phys Chem B 2005;109:18195-200. .