CATH Classification

Domain Context

CATH Clusters

Superfamily Porphobilinogen deaminase, C-terminal domain
Functional Family Porphobilinogen deaminase

Enzyme Information

2.5.1.61
Hydroxymethylbilane synthase.
based on mapping to UniProt P06983
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)

P06983
HEM3_ECOLI
Escherichia coli K-12
Porphobilinogen deaminase

PDB Structure

PDB 1GTK
External Links
Method X-RAY DIFFRACTION
Organism
Primary Citation
Time-Resolved and Static-Ensemble Structural Chemistry of Hydroxymethylbilane Synthase
Helliwell, J.R., Nieh, Y.P., Habash, J., Faulder, P.F., Raftery, J., Cianci, M., Wulff, M., Hadener, A.
Faraday Discuss.