These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Substrate modulation of the properties and reactivity of the oxy-ferrous and hydroperoxo-ferric intermediates of cytochrome P450cam as shown by cryoreduction-EPR/ENDOR spectroscopy.
    Author: Davydov R, Perera R, Jin S, Yang TC, Bryson TA, Sono M, Dawson JH, Hoffman BM.
    Journal: J Am Chem Soc; 2005 Feb 09; 127(5):1403-13. PubMed ID: 15686372.
    Abstract:
    EPR/ENDOR studies have been carried out on oxyferrous cytochrome P450cam one-electron cryoreduced by gamma-irradiation at 77 K in the absence of substrate and in the presence of a variety of substrates including its native hydroxylation substrate, camphor (a), and the alternate substrates, 5-methylenyl-camphor (b), 5,5-difluorocamphor (c), norcamphor (d), and adamantanone (e); the equivalent experiments have been performed on the T252A mutant complexed with a and b. The present study shows that the properties and reactivity of the oxyheme and of both the primary and the annealed intermediates are modulated by a bound substrate. This includes alterations in the properties of the heme center itself (g tensor; (14)N, (1)H, hyperfine couplings). It also includes dramatic changes in reactivity: the presence of any substrate increases the lifetime of hydroperoxoferri-P450cam (2) no less than ca. 20-fold. Among the substrates, b stands out as having an exceptionally strong influence on the properties and reactivity of the P450cam intermediates, especially in the T252A mutant. The intermediate, 2(T252A)-b, does not lose H(2)O(2), as occurs with 2(T252A)-a, but decays with formation of the epoxide of b. Thus, these observations show that substrate can modulate the properties of both the monoxygenase active-oxygen intermediates and the proton-delivery network that encompasses them.
    [Abstract] [Full Text] [Related] [New Search]