Site-specific spin trapping of tyrosine radicals in the oxidation of metmyoglobin by hydrogen peroxide
The reaction between metmyoglobin and hydrogen peroxide produces both a ferryl-oxo heme and a globin-centred radical(s) from the two oxidizing equivalents of the hydrogen peroxide. Evidence has been presented for localization of the globin-centred radical on one tryptophan residue and tyrosines 103...
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Portland Press Ltd.
1998
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Online Access: | http://dx.doi.org/10.1042/bj3301293 https://portlandpress.com/biochemj/article-pdf/330/3/1293/632371/bj3301293.pdf |
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crportlandpress:10.1042/bj3301293 2024-09-15T18:37:35+00:00 Site-specific spin trapping of tyrosine radicals in the oxidation of metmyoglobin by hydrogen peroxide GUNTHER, R. Michael TSCHIRRET-GUTH, Richard A. WITKOWSKA, H. Ewa FANN, C. Yang BARR, P. David ORTIZ DE MONTELLANO, Paul R. MASON, P. Ronald 1998 http://dx.doi.org/10.1042/bj3301293 https://portlandpress.com/biochemj/article-pdf/330/3/1293/632371/bj3301293.pdf en eng Portland Press Ltd. Biochemical Journal volume 330, issue 3, page 1293-1299 ISSN 0264-6021 1470-8728 journal-article 1998 crportlandpress https://doi.org/10.1042/bj3301293 2024-06-27T04:18:27Z The reaction between metmyoglobin and hydrogen peroxide produces both a ferryl-oxo heme and a globin-centred radical(s) from the two oxidizing equivalents of the hydrogen peroxide. Evidence has been presented for localization of the globin-centred radical on one tryptophan residue and tyrosines 103 and 151. When the spin-trapping agent 5,5-dimethyl-1-pyrroline N-oxide (DMPO) is included in the reaction mixture, a radical adduct has been detected, but the residue at which that adduct is formed has not been determined. Replacement of either tryptophans 7 and 14 or tyrosines 146 and 151 with phenylalanine has no effect on the formation of DMPO adduct in the reaction with hydrogen peroxide. When tyrosine 103 is replaced with phenylalanine, however, only DMPOX, a product of the oxidation of the spin-trap, is detected. Tyrosine-103 is, therefore, the site of radical adduct formation with DMPO. The spin trap 2-methyl-2-nitrosopropane (MNP), however, forms radical adducts with any recombinant sperm whale metmyoglobin that contains either tyrosine 103 or 151. Detailed spectral analysis of the DMPO and MNP radical adducts of isotopically substituted tyrosine radical yield complete structural determinations. The multiple sites of trapping support a model in which the unpaired electron density is spread over a number of residues in the population of metmyoglobin molecules, at least some of which are in equilibrium with each other. Article in Journal/Newspaper Sperm whale Portland Press Biochemical Journal 330 3 1293 1299 |
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Portland Press |
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English |
description |
The reaction between metmyoglobin and hydrogen peroxide produces both a ferryl-oxo heme and a globin-centred radical(s) from the two oxidizing equivalents of the hydrogen peroxide. Evidence has been presented for localization of the globin-centred radical on one tryptophan residue and tyrosines 103 and 151. When the spin-trapping agent 5,5-dimethyl-1-pyrroline N-oxide (DMPO) is included in the reaction mixture, a radical adduct has been detected, but the residue at which that adduct is formed has not been determined. Replacement of either tryptophans 7 and 14 or tyrosines 146 and 151 with phenylalanine has no effect on the formation of DMPO adduct in the reaction with hydrogen peroxide. When tyrosine 103 is replaced with phenylalanine, however, only DMPOX, a product of the oxidation of the spin-trap, is detected. Tyrosine-103 is, therefore, the site of radical adduct formation with DMPO. The spin trap 2-methyl-2-nitrosopropane (MNP), however, forms radical adducts with any recombinant sperm whale metmyoglobin that contains either tyrosine 103 or 151. Detailed spectral analysis of the DMPO and MNP radical adducts of isotopically substituted tyrosine radical yield complete structural determinations. The multiple sites of trapping support a model in which the unpaired electron density is spread over a number of residues in the population of metmyoglobin molecules, at least some of which are in equilibrium with each other. |
format |
Article in Journal/Newspaper |
author |
GUNTHER, R. Michael TSCHIRRET-GUTH, Richard A. WITKOWSKA, H. Ewa FANN, C. Yang BARR, P. David ORTIZ DE MONTELLANO, Paul R. MASON, P. Ronald |
spellingShingle |
GUNTHER, R. Michael TSCHIRRET-GUTH, Richard A. WITKOWSKA, H. Ewa FANN, C. Yang BARR, P. David ORTIZ DE MONTELLANO, Paul R. MASON, P. Ronald Site-specific spin trapping of tyrosine radicals in the oxidation of metmyoglobin by hydrogen peroxide |
author_facet |
GUNTHER, R. Michael TSCHIRRET-GUTH, Richard A. WITKOWSKA, H. Ewa FANN, C. Yang BARR, P. David ORTIZ DE MONTELLANO, Paul R. MASON, P. Ronald |
author_sort |
GUNTHER, R. Michael |
title |
Site-specific spin trapping of tyrosine radicals in the oxidation of metmyoglobin by hydrogen peroxide |
title_short |
Site-specific spin trapping of tyrosine radicals in the oxidation of metmyoglobin by hydrogen peroxide |
title_full |
Site-specific spin trapping of tyrosine radicals in the oxidation of metmyoglobin by hydrogen peroxide |
title_fullStr |
Site-specific spin trapping of tyrosine radicals in the oxidation of metmyoglobin by hydrogen peroxide |
title_full_unstemmed |
Site-specific spin trapping of tyrosine radicals in the oxidation of metmyoglobin by hydrogen peroxide |
title_sort |
site-specific spin trapping of tyrosine radicals in the oxidation of metmyoglobin by hydrogen peroxide |
publisher |
Portland Press Ltd. |
publishDate |
1998 |
url |
http://dx.doi.org/10.1042/bj3301293 https://portlandpress.com/biochemj/article-pdf/330/3/1293/632371/bj3301293.pdf |
genre |
Sperm whale |
genre_facet |
Sperm whale |
op_source |
Biochemical Journal volume 330, issue 3, page 1293-1299 ISSN 0264-6021 1470-8728 |
op_doi |
https://doi.org/10.1042/bj3301293 |
container_title |
Biochemical Journal |
container_volume |
330 |
container_issue |
3 |
container_start_page |
1293 |
op_container_end_page |
1299 |
_version_ |
1810481946986283008 |