Table 3.
Characterization of the nonenzymatic reduction of nitrotyrosine
| Compounds added | Nitrotyrosine conversion, % |
|---|---|
| Hemoglobin, 25 μM | |
| +9.0 mM DTT | 100% |
| +7.2 mM DTT | 40% |
| +3.6 mM DTT | 5% |
| +1.8 mM DTT | 0% |
| +0.9 mM DTT | 0% |
| Hemoglobin, 25 μM | |
| +100 mM cysteine | 0% |
| +100 mM glutathione | 0% |
| +10 mM β-mercaptoethanol | 0% |
| +350 mM β-mercaptoethanol | 100% |
| +100 mM ascorbic acid | 12% |
| Hemoglobin, 25 μM with 10 mM DTT | |
| +100 mM cystamine | 5% |
| +20 mM diamide | 0% |
| +20 mM mercuric chloride | 0% |
| Hemoglobin, 25 μM with 10 mM DTT | |
| +0.1 mM KCN | 100% |
| +0.1 mM SNP | 100% |
| +0.1 mM SNAP | 100% |
| +0.1 mM GSNO | 100% |
| +0.1 mM DETA-NO | 0% |
| Hemoglobin, 25 μM with 10 mM DTT | |
| pH 10 Glycine buffer | 70% |
| Borate buffer (10) | 87% |
| pH 7 Tricine buffer (7.0) | 100% |
| Phosphate buffer (7.2) | 100% |
| pH 4 Acetate buffer (4.0) | 10% |
| Citrate buffer (4.5) | 31% |
Nitrotyrosine (100 nmol) was incubated with indicated amounts of tested compounds. An equivalent of 180 pmol of nitrotyrosine was applied on the HPLC and analyzed by ECD. The percentage of conversion was calculated by the comparison with amount of detected nitrotyrosine in the sample lacking DTT and hemoglobin. Data from a representative experiment are presented. SNP, sodium nitroprusside; SNAP, S-nitroso-N-acetyl-d, l-penicillamine; DETA-NO, (z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl)amino] diazen-1-ium-1, 2-diolate; GSNO, S-nitrosoglutathione.