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Model compounds for the active site selenocysteine of glutathione peroxidase: A 77 Se NMR study
Author(s) -
Dowd Diane,
Gettins Peter
Publication year - 1988
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260260102
Subject(s) - chemistry , selenide , selenocysteine , selenium , sulfide , hydrogen peroxide , proton nmr , peroxidase , nmr spectra database , hydrogen sulfide , glutathione peroxidase , carbon 13 nmr , fluorine 19 nmr , nuclear magnetic resonance spectroscopy , glutathione , stereochemistry , organic chemistry , enzyme , spectral line , sulfur , cysteine , physics , astronomy
To test the feasibility of using 77 Se NMR to distinguish between different proposed mechanisms of action of the selenoenzyme glutathione peroxidase, model compounds containing the proposed selenium moieties have been synthesized and their 77 Se NMR spectra recorded. It was found that the difference in chemical shift between the two proposed resting states, selenol or selenenic acid, is approximately 1300 ppm. For the next step, oxidation by hydrogen peroxide, a much smaller difference of about 100 ppm was found between selenenic and seleninic acid species. The products of the second reaction step, selenide sulfide vs selenoxide sulfide, differed in chemical shift by about 470 ppm. It was concluded that, for two of the three states of the enzyme, 77 Se NMR could, in principle, be used unambiguously to distinguish between the two proposed mechanisms.