CATH Classification

Domain Context

CATH Clusters

Superfamily Porphobilinogen deaminase, C-terminal domain
Functional Family porphobilinogen deaminase isoform X1

Enzyme Information

2.5.1.61
Hydroxymethylbilane synthase.
based on mapping to UniProt P08397
4 porphobilinogen + H(2)O = hydroxymethylbilane + 4 NH(3).
-!- The enzyme works by stepwise addition of pyrrolylmethyl groups until a hexapyrrole is present at the active center. -!- The terminal tetrapyrrole is then hydrolyzed to yield the product, leaving a cysteine-bound dipyrrole on which assembly continues. -!- In the presence of a second enzyme, EC 4.2.1.75, which is often called cosynthase, the product is cyclized to form uroporphyrinogen III. -!- If EC 4.2.1.75 is absent, the hydroxymethylbilane cyclizes spontaneously to form uroporphyrinogen I. -!- Formerly EC 4.3.1.8.

UniProtKB Entries (1)

P08397
HEM3_HUMAN
Homo sapiens
Porphobilinogen deaminase

PDB Structure

PDB 5M7F
External Links
Method X-RAY DIFFRACTION
Organism
Primary Citation
Structural basis of pyrrole polymerization in human porphobilinogen deaminase.
Pluta, P., Roversi, P., Bernardo-Seisdedos, G., Rojas, A.L., Cooper, J.B., Gu, S., Pickersgill, R.W., Millet, O.
Biochim Biophys Acta Gen Subj