Because the enzyme nitrogenase, responsible for nitrogen fixation, is very sensitive to oxygen which will inhibit it irreversibly, all nitrogen-fixing organisms must possess some mechanism to keep the concentration of oxygen low.
Como o encima nitroxenase, responsable da fixación do nitróxeno, é moi sensible ao oxíxeno que a inhibe irreversiblemente, todos os organismos fixadores do nitróxeno deben ter algún mecanismo para manteren a concentración de oxíxeno baixa.