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Fast ferrous heme–NO oxidation in nitric oxide synthases
Author(s) -
Tejero Jesús,
Santolini Jérôme,
Stuehr Dennis J.
Publication year - 2009
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2009.07157.x
Subject(s) - heme , ferrous , chemistry , nitric oxide , nitric oxide synthase , hemeprotein , enzyme , catalysis , biochemistry , organic chemistry
During catalysis, the heme in nitric oxide synthase (NOS) binds NO before releasing it to the environment. Oxidation of the NOS ferrous heme–NO complex by O 2 is key for catalytic cycling, but the mechanism is unclear. We utilized stopped‐flow methods to study the reaction of O 2 with ferrous heme–NO complexes of inducible and neuronal NOS enzymes. We found that the reaction does not involve heme–NO dissociation, but instead proceeds by a rapid direct reaction of O 2 with the ferrous heme–NO complex. This behavior is novel and may distinguish heme–thiolate enzymes, such as NOS, from related heme proteins.