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Updated: May 25, 2026
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Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds
Published on: February 16, 2022
Is S-nitrosocysteine a true surrogate for nitric oxide?
Jason R Hickok1, Divya Vasudevan, Gregory R J Thatcher
1Department of Medicinal Chemistry & Pharmacognosy, University of Illinois at Chicago, 60612-7231, USA.
Antioxidants & Redox Signaling
|February 7, 2012
Summary
S-Nitrosothiol (RSNO) and dinitrosyliron complexes (DNIC) are key nitric oxide (NO) products. CysNO is not a reliable NO surrogate, as it forms more RSNO than DNIC, unlike physiological NO.
Area of Science:
- Biochemistry
- Cellular Biology
- Nitric Oxide Signaling
Background:
- Nitric oxide (NO) mediates biological effects through S-nitrosothiol (RSNO) formation.
- RSNOs are formed via auto-oxidation, transnitrosation, oxidative nitrosylation, or dinitrosyliron complexes (DNIC).
- Free NO and S-nitrosocysteine (CysNO) are common tools to study NO biology, assuming analogous cellular effects.
Purpose of the Study:
- To quantitatively compare the formation of RSNO and DNIC from both free NO and CysNO.
- To evaluate the suitability of CysNO as a surrogate for studying physiological NO signaling.
- To investigate the role of chelatable iron in the formation of NO-derived products.
Main Methods:
- Incubation of RAW 264.7 cells with free NO (generated by NO donors) or CysNO.
- Quantitative analysis of intracellular RSNO and DNIC formation.
- Assessment of the requirement for chelatable iron in product formation.
Main Results:
- Both free NO and CysNO led to intracellular RSNO and DNIC formation.
- DNIC were the dominant products from physiological NO concentrations, while RSNO predominated from CysNO.
- Chelatable iron was essential for DNIC formation from both NO sources but not for RSNO formation.
Conclusions:
- Significant differences exist in RSNO and DNIC formation between free NO and CysNO.
- CysNO is not a reliable surrogate for physiological NO due to distinct product profiles.
- Researchers must consider these differences when designing experiments on NO signaling mechanisms.
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