Abstract
Sinapinic acid (3,5-dimethoxy-4-hydroxycinnamic acid, SA) reacted with peroxynitrous acid at neutral pH with a second-order rate constant of 812M-1s-1, to yield a red product (λmax, 532nm). The identical colored product could be formed with acidified decomposed peroxynitrous acid solutions or nitrite at slower rates (0.1M HCl, 8.32M-1s-1; 10% acetic acid, 0.0004M-1s-1). The red compound is thought to be O-nitrososinapinic acid (3,5-dimethoxy-4-nitrosooxycinnamic acid) which can be formed by reaction with either peroxynitrous acid or nitrous acid. The extinction coefficient of O-nitrososinapinic acid (ONSA) was estimated to be 8419M-1cm-1 at 510nm in 10% acetic acid and 90% acetonitrile. ONSA was also formed via NO+ transfer from S-nitrosoglutathione (GSNO). ONSA in turn can S-nitrosate low molecular weight thiols and protein thiols. SA was also shown to act as a peroxynitrite sink as it effectively prevented the oxidation of dihydrorhodamine under physiological conditions. The fact that O-nitrososinapinic acid is stable and can be used to S-nitrosate thiol containing amino acids, peptides, and proteins makes it a potentially useful reagent in the study of S-nitrosothiol biochemistry and physiology. In addition, the relatively high extinction coefficient of O-nitrososinapinic acid means that it could be utilized as an analyte for the spectroscopic detection of peroxynitrite or NO+-donors in the submicromolar range.
Original language | English (US) |
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Pages (from-to) | 214-221 |
Number of pages | 8 |
Journal | Nitric Oxide - Biology and Chemistry |
Volume | 8 |
Issue number | 4 |
DOIs | |
State | Published - Jun 2003 |
Externally published | Yes |
Keywords
- NO donors
- O-Nitrososinapinic acid
- Peroxynitrite
- S-Nitrosation
- SIN-1
- Sinapinic acid
ASJC Scopus subject areas
- Biochemistry
- Physiology
- Clinical Biochemistry
- Cancer Research