Urease

Possible mechanism of urea degradation

  The oxygen atom of urea binds to the open sixth coordination site of
  Ni atom 1.

  A hydrogen bond to the histidine residue is formed (HIS 219).

  Another hydrogen bond is formed between the histidine residue (HIS 320)
  and the neighbouring N atom of urea.

  A bond is formed between the C atom of urea and the water molecule
  bound to Ni atom 2.

  Proton transfer from the histidine residue (HIS 320) to one of the amine
  groups of urea.

  Ammonia (NH₃) is released.

  Bond between oxygen and Ni²⁺ ion 2 is broken.

  Carbamic acid is formed and released.

  Carbamic acid decays to ammonia and carbon dioxide.