TY - JOUR
T1 - Peroxynitrite-mediated modification of proteins at physiological carbon dioxide concentration
T2 - pH dependence of carbonyl formation, tyrosine nitration, and methionine oxidation
AU - Tien, Ming
AU - Berlett, Barbara S.
AU - Levine, Rodney L.
AU - Chock, P. Boon
AU - Stadtman, Earl R.
PY - 1999/7/6
Y1 - 1999/7/6
N2 - The ability of peroxynitrite to modify amino acid residues in glutamine synthetase (GS) and BSA is greatly influenced by pH and CO2. At physiological concentrations of CO2 (1.3 mM), the generation of carbonyl groups (0.2-0.4 equivalents/subunit) is little affected by pH over the range of 7.2-9.0, but, in the absence of CO2, carbonyl formation increases (from 0.1- 1.2 equivalents/subunit) as the pH is raised from 7.2 to 10.5. This increase is attributable, in part but not entirely, to the increase in peroxynitrite (PN) stability with increasing pH. Of several amino acid polymers tested, only those containing lysine residues yielded carbonyl derivatives. In contrast, the nitration of tyrosine residues of both GS and BSA at pH 7.5 almost completely depends on the presence of CO2. However, the pH profiles of tyrosine nitration in GS and BSA are not the same. With both proteins, nitration decreases ≃65% with increasing pH over the range of 7.2- 8.4, but, then in the case of GS only, there is a 3.4-fold increase in the level of nitration over the range pH 8.4-8.8. The oxidation of methionine residues in both proteins and in the tripeptide Ala-Met-Ala was inhibited by CO2 at both high and low pH values. These results emphasize the importance of controlling the pH and CO2 concentrations in studies involving PN and indicate that PN is not likely to contribute appreciably to carbonyl formation or oxidation of methionine residues of proteins at physiological pH and CO2 concentrations.
AB - The ability of peroxynitrite to modify amino acid residues in glutamine synthetase (GS) and BSA is greatly influenced by pH and CO2. At physiological concentrations of CO2 (1.3 mM), the generation of carbonyl groups (0.2-0.4 equivalents/subunit) is little affected by pH over the range of 7.2-9.0, but, in the absence of CO2, carbonyl formation increases (from 0.1- 1.2 equivalents/subunit) as the pH is raised from 7.2 to 10.5. This increase is attributable, in part but not entirely, to the increase in peroxynitrite (PN) stability with increasing pH. Of several amino acid polymers tested, only those containing lysine residues yielded carbonyl derivatives. In contrast, the nitration of tyrosine residues of both GS and BSA at pH 7.5 almost completely depends on the presence of CO2. However, the pH profiles of tyrosine nitration in GS and BSA are not the same. With both proteins, nitration decreases ≃65% with increasing pH over the range of 7.2- 8.4, but, then in the case of GS only, there is a 3.4-fold increase in the level of nitration over the range pH 8.4-8.8. The oxidation of methionine residues in both proteins and in the tripeptide Ala-Met-Ala was inhibited by CO2 at both high and low pH values. These results emphasize the importance of controlling the pH and CO2 concentrations in studies involving PN and indicate that PN is not likely to contribute appreciably to carbonyl formation or oxidation of methionine residues of proteins at physiological pH and CO2 concentrations.
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U2 - 10.1073/pnas.96.14.7809
DO - 10.1073/pnas.96.14.7809
M3 - Article
C2 - 10393903
AN - SCOPUS:0033529262
SN - 0027-8424
VL - 96
SP - 7809
EP - 7814
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 14
ER -