4 porphobilinogen + H2O => hydroxymethylbilane + 4 NH3 (Gallus gallus)
4 porphobilinogen + h2o => hydroxymethylbilane + 4 nh3 (gallus gallus)
4 porphobilinogen + H2O => hydroxymethylbilane + 4 NH3 (Gallus gallus)
4 porphobilinogen + h2o => hydroxymethylbilane + 4 nh3 (gallus gallus)