Interaction of the mechanism-based inactivator acetylene with ammonia monooxygenase of Nitrosomonas europaea

• DOI: 10.1099/mic.0.023721-0
• Publication Date: 2008-12-31T23:06:09Z
• Authors: Stefan Gilch; Manja Vogel; Matthias W. Lorenz; Ortwin Meyer; Ingo Schmidt
• Keywords: Nitrosomonas europaea; Ammonia monooxygenase; Acetylene; Hydroxylamine; Nitrosomonas

The ammonia monooxygenase (AMO) of Nitrosomonas europaea is a metalloenzyme that catalyses the oxidation to hydroxylamine. We have identified histidine 191 AmoA as binding site for oxidized mechanism-based inactivator acetylene. Binding acetylene changed molecular mass His-191 from 155.15 197.2 Da (+42.05), providing evidence was ketene (CH2CO; 42.04 Da) which binds specifically His-191. It must be assumed part acetylene-activating in AMO or at least directly neighbours this site.