Tryptophan residues are targets in hypothiocyanous acid-mediated protein oxidation

Clare Louise Hawkins; David I Pattison; Naomi R Stanley; Michael Jonathan Davies

doi:10.1042/BJ20070941

Tryptophan residues are targets in hypothiocyanous acid-mediated protein oxidation

Clare Louise Hawkins, David I Pattison, Naomi R Stanley, Michael Jonathan Davies

41 Citationer (Scopus)

Abstract

Myeloperoxidase, released by activated phagocytes, forms reactive oxidants by catalysing the reaction of halide and pseudo-halide ions with H(2)O(2). These oxidants have been linked to tissue damage in a range of inflammatory diseases. With physiological levels of halide and pseudo-halide ions, similar amounts of HOCl (hypochlorous acid) and HOSCN (hypothiocyanous acid) are produced by myeloperoxidase. Although the importance of HOSCN in initiating cellular damage via thiol oxidation is becoming increasingly recognized, there are limited data on the reactions of HOSCN with other targets. In the present study, the products of the reaction of HOSCN with proteins has been studied. With albumin, thiols are oxidized preferentially forming unstable sulfenyl thiocyanate derivatives, as evidenced by the reversible incorporation of (14)C from HOS(14)CN. On consumption of the HSA (human serum albumin) free thiol group, the formation of stable (14)C-containing products and oxidation of tryptophan residues are observed. Oxidation of tryptophan residues is observed on reaction of HOSCN with other proteins (including myoglobin, lysozyme and trypsin inhibitor), but not free tryptophan, or tryptophan-containing peptides. Peptide mass mapping studies with HOSCN-treated myoglobin, showed the addition of two oxygen atoms on either Trp(7) or Trp(14) with equimolar or less oxidant, and the addition of a further two oxygen atoms to the other tryptophan with higher oxidant concentrations (> or = 2-fold). Tryptophan oxidation was observed on treating myoglobin with HOSCN in the presence of glutathione and ascorbate. Thus tryptophan residues are likely to be favourable targets for the reaction in biological systems, and the oxidation products formed may be useful biomarkers of HOSCN-mediated protein oxidation.

Originalsprog	Engelsk
Tidsskrift	Biochemical Journal
Vol/bind	416
Udgave nummer	3
Sider (fra-til)	441-52
Antal sider	12
ISSN	0264-6021
DOI	https://doi.org/10.1042/BJ20070941
Status	Udgivet - 15 dec. 2008
Udgivet eksternt	Ja

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@article{adffeb97568242db9ee57d88a8658023,

title = "Tryptophan residues are targets in hypothiocyanous acid-mediated protein oxidation",

abstract = "Myeloperoxidase, released by activated phagocytes, forms reactive oxidants by catalysing the reaction of halide and pseudo-halide ions with H(2)O(2). These oxidants have been linked to tissue damage in a range of inflammatory diseases. With physiological levels of halide and pseudo-halide ions, similar amounts of HOCl (hypochlorous acid) and HOSCN (hypothiocyanous acid) are produced by myeloperoxidase. Although the importance of HOSCN in initiating cellular damage via thiol oxidation is becoming increasingly recognized, there are limited data on the reactions of HOSCN with other targets. In the present study, the products of the reaction of HOSCN with proteins has been studied. With albumin, thiols are oxidized preferentially forming unstable sulfenyl thiocyanate derivatives, as evidenced by the reversible incorporation of (14)C from HOS(14)CN. On consumption of the HSA (human serum albumin) free thiol group, the formation of stable (14)C-containing products and oxidation of tryptophan residues are observed. Oxidation of tryptophan residues is observed on reaction of HOSCN with other proteins (including myoglobin, lysozyme and trypsin inhibitor), but not free tryptophan, or tryptophan-containing peptides. Peptide mass mapping studies with HOSCN-treated myoglobin, showed the addition of two oxygen atoms on either Trp(7) or Trp(14) with equimolar or less oxidant, and the addition of a further two oxygen atoms to the other tryptophan with higher oxidant concentrations (> or = 2-fold). Tryptophan oxidation was observed on treating myoglobin with HOSCN in the presence of glutathione and ascorbate. Thus tryptophan residues are likely to be favourable targets for the reaction in biological systems, and the oxidation products formed may be useful biomarkers of HOSCN-mediated protein oxidation.",

keywords = "Amino Acid Sequence, Antioxidants, Ascorbic Acid, Fluorescent Dyes, Glutathione, Humans, Hypochlorous Acid, Molecular Sequence Data, Molecular Structure, Myoglobin, Oxidation-Reduction, Peptide Fragments, Peptide Mapping, Protein Denaturation, Serum Albumin, Sulfhydryl Compounds, Thiocyanates, Tryptophan",

author = "Hawkins, {Clare Louise} and Pattison, {David I} and Stanley, {Naomi R} and Davies, {Michael Jonathan}",

year = "2008",

month = dec,

day = "15",

doi = "10.1042/BJ20070941",

language = "English",

volume = "416",

pages = "441--52",

journal = "Biochemical Journal",

issn = "0264-6021",

publisher = "Portland Press Ltd.",

number = "3",

}

TY - JOUR

T1 - Tryptophan residues are targets in hypothiocyanous acid-mediated protein oxidation

AU - Hawkins, Clare Louise

AU - Pattison, David I

AU - Stanley, Naomi R

AU - Davies, Michael Jonathan

PY - 2008/12/15

Y1 - 2008/12/15

N2 - Myeloperoxidase, released by activated phagocytes, forms reactive oxidants by catalysing the reaction of halide and pseudo-halide ions with H(2)O(2). These oxidants have been linked to tissue damage in a range of inflammatory diseases. With physiological levels of halide and pseudo-halide ions, similar amounts of HOCl (hypochlorous acid) and HOSCN (hypothiocyanous acid) are produced by myeloperoxidase. Although the importance of HOSCN in initiating cellular damage via thiol oxidation is becoming increasingly recognized, there are limited data on the reactions of HOSCN with other targets. In the present study, the products of the reaction of HOSCN with proteins has been studied. With albumin, thiols are oxidized preferentially forming unstable sulfenyl thiocyanate derivatives, as evidenced by the reversible incorporation of (14)C from HOS(14)CN. On consumption of the HSA (human serum albumin) free thiol group, the formation of stable (14)C-containing products and oxidation of tryptophan residues are observed. Oxidation of tryptophan residues is observed on reaction of HOSCN with other proteins (including myoglobin, lysozyme and trypsin inhibitor), but not free tryptophan, or tryptophan-containing peptides. Peptide mass mapping studies with HOSCN-treated myoglobin, showed the addition of two oxygen atoms on either Trp(7) or Trp(14) with equimolar or less oxidant, and the addition of a further two oxygen atoms to the other tryptophan with higher oxidant concentrations (> or = 2-fold). Tryptophan oxidation was observed on treating myoglobin with HOSCN in the presence of glutathione and ascorbate. Thus tryptophan residues are likely to be favourable targets for the reaction in biological systems, and the oxidation products formed may be useful biomarkers of HOSCN-mediated protein oxidation.

AB - Myeloperoxidase, released by activated phagocytes, forms reactive oxidants by catalysing the reaction of halide and pseudo-halide ions with H(2)O(2). These oxidants have been linked to tissue damage in a range of inflammatory diseases. With physiological levels of halide and pseudo-halide ions, similar amounts of HOCl (hypochlorous acid) and HOSCN (hypothiocyanous acid) are produced by myeloperoxidase. Although the importance of HOSCN in initiating cellular damage via thiol oxidation is becoming increasingly recognized, there are limited data on the reactions of HOSCN with other targets. In the present study, the products of the reaction of HOSCN with proteins has been studied. With albumin, thiols are oxidized preferentially forming unstable sulfenyl thiocyanate derivatives, as evidenced by the reversible incorporation of (14)C from HOS(14)CN. On consumption of the HSA (human serum albumin) free thiol group, the formation of stable (14)C-containing products and oxidation of tryptophan residues are observed. Oxidation of tryptophan residues is observed on reaction of HOSCN with other proteins (including myoglobin, lysozyme and trypsin inhibitor), but not free tryptophan, or tryptophan-containing peptides. Peptide mass mapping studies with HOSCN-treated myoglobin, showed the addition of two oxygen atoms on either Trp(7) or Trp(14) with equimolar or less oxidant, and the addition of a further two oxygen atoms to the other tryptophan with higher oxidant concentrations (> or = 2-fold). Tryptophan oxidation was observed on treating myoglobin with HOSCN in the presence of glutathione and ascorbate. Thus tryptophan residues are likely to be favourable targets for the reaction in biological systems, and the oxidation products formed may be useful biomarkers of HOSCN-mediated protein oxidation.

KW - Amino Acid Sequence

KW - Antioxidants

KW - Ascorbic Acid

KW - Fluorescent Dyes

KW - Glutathione

KW - Humans

KW - Hypochlorous Acid

KW - Molecular Sequence Data

KW - Molecular Structure

KW - Myoglobin

KW - Oxidation-Reduction

KW - Peptide Fragments

KW - Peptide Mapping

KW - Protein Denaturation

KW - Serum Albumin

KW - Sulfhydryl Compounds

KW - Thiocyanates

KW - Tryptophan

U2 - 10.1042/BJ20070941

DO - 10.1042/BJ20070941

M3 - Journal article

C2 - 18652572

SN - 0264-6021

VL - 416

SP - 441

EP - 452

JO - Biochemical Journal

JF - Biochemical Journal

IS - 3

ER -

Tryptophan residues are targets in hypothiocyanous acid-mediated protein oxidation

Abstract

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