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Kinetic solvent isotope effect in steady‐state turnover by CYP19A1 suggests involvement of Compound 1 for both hydroxylation and aromatization steps
Author(s) -
Khatri Yogan,
Luthra Abhinav,
Duggal Ruchia,
Sligar Stephen G.
Publication year - 2014
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2014.06.050
Subject(s) - aromatization , hydroxylation , chemistry , kinetic isotope effect , aromatase , aldehyde , reaction intermediate , solvent , stereochemistry , deuterium , catalysis , enzyme , biochemistry , biology , genetics , physics , quantum mechanics , cancer , breast cancer
CYP19A1, or human aromatase catalyzes the conversion of androgens to estrogens in a three‐step reaction through the formation of 19‐hydroxy and 19‐aldehyde intermediates. While the first two steps of hydroxylation are thought to proceed through a high‐valent iron‐oxo species, controversy exists surrounding the identity of the reaction intermediate that catalyzes the lyase and aromatization reaction. We investigated the kinetic isotope effect on the steady‐state turnover of Nanodisc‐incorporated human CYP19A1 to explore the mechanisms of this reaction. Our experiments reveal a significant (∼2.5) kinetic solvent isotope effect for the C10–C19 lyase reaction, similar to that of the first two hydroxylation steps (2.7 and 1.2). These data implicate the involvement of Compound 1 as a reactive intermediate in the final aromatization step of CYP19A1.