Heme environment in aldoxime dehydratase involved in carbon-nitrogen triple bond synthesis
Ken-Ichi Oinuma1, Takehiro Ohta, Kazunobu Konishi
1Institute of Applied Biochemistry, The University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
Abstract:
Resonance Raman spectra have been measured to characterize the heme environment in aldoxime dehydratase (OxdA), a novel hemoprotein, which catalyzes the dehydration of aldoxime into nitrile. The spectra showed that the ferric heme in the enzyme is six-coordinate low spin, whereas the ferrous heme is five-coordinate high spin. We assign a prominent vibration that occurs at 226 cm(-1) in the ferrous enzyme to the Fe-proximal histidine stretching vibration. In the CO-bound form of OxdA, the correlation between the Fe-CO stretching (512 cm(-1)) and C-O stretching (1950 cm(-1)) frequencies also supports our assignment of proximal histidine coordination.
More Related Videos
Related Concept Videos
Aldehydes and Ketones with Amines: Enamine Formation Mechanism
Dehydration of Aldols to Enals: Base-Catalyzed Aldol Condensation
Aldehydes and Ketones with Amines: Imine Formation Mechanism
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
Dehydration of Aldols to Enones: Acid-Catalyzed Aldol Condensation
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
Aldehydes and Ketones with HCN: Cyanohydrin Formation Mechanism


