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1 H nuclear relaxation study of the aniline‐binding site in human hemoglobin
Author(s) -
Sheridan Robert P.,
Gupta Raj K.
Publication year - 1981
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560200723
Subject(s) - aniline , chemistry , methemoglobin , hemoglobin , proton , histidine , photochemistry , hydroxylation , ferric , proton nmr , relaxation (psychology) , inorganic chemistry , stereochemistry , organic chemistry , enzyme , social psychology , psychology , physics , quantum mechanics
Hemoglobin‐catalyzed hydroxylation of aniline may be taken as a model for similar reactions catalyzed by cytochrome P‐450. Using ultraviolet‐difference spectroscopy and 1 H nuclear relaxation techniques, the binding of aniline to hemoglobin was examined. From the magnitude of paramagnetic effects of ferric iron on aniline protons, using the correlation time determined from the magnetic field dependence of water proton relaxation rates, aniline was found to bind to methemoglobins such that the aromatic protons are 8.5 ± 0.7 Å, away from the high‐spin Fe 3+ . A mode of binding is proposed where the aniline molecule is hydrogen bonded to the distal histidine of hemoglobin.