Nitrile hydratase

[3] NHases have been efficiently used for the industrial production of acrylamide from acrylonitrile[4] on a scale of 600 000 tons per annum,[5] and for removal of nitriles from wastewater.

Photosensitive NHases intrinsically possess nitric oxide (NO) bound to the iron centre, and its photodissociation activates the enzyme.

The α subunit consists of a long extended N-terminal "arm", containing two α-helices, and a C-terminal domain with an unusual four-layered structure (α-β-β-α).

An assembly pathway for nitrile hydratase was first proposed when gel filtration experiments found that the complex exists in both αβ and α2β2 forms.

[9] In vitro experiments using mass spectrometry further revealed that the α and β subunits first assemble to form the αβ dimer.

The sixth position, accessible to the active site cleft, is occupied either by NO or by a solvent-exchangeable ligand (hydroxide or water).