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Interaction of nitric oxide with photoexcited rose bengal: evidence for one-electron reduction of nitric oxide to nitroxyl anion. Arch Biochem Biophys 1995 Dec 20;324(2):367-73

Date

12/20/1995

Pubmed ID

8554328

DOI

10.1006/abbi.1995.0049

Scopus ID

2-s2.0-0029584586 (requires institutional sign-in at Scopus site)   9 Citations

Abstract

The interaction of nitric oxide (.NO) with Rose Bengal (RB) in the presence of electron donors was investigated. Upon illumination of a mixture of RB and .NO with visible light, an enhancement in the rate of .NO consumption was observed that increased with increasing RB concentration. In the presence of electron donors (NADH, glutathione, or ascorbate), the rates of .NO depletion increased further. NADH enhanced .NO depletion to a greater extent than either glutathione or ascorbate. Photoactivated RB under anaerobic conditions reacts with NADH to form the RB anion radical (RB.-), which has a characteristic visible absorption band centered at 418 nm. Rose Bengal anion radical disporportionates to give RB and a colorless reduced form of RB, RBH-. The net result of this process is the photobleaching of RB. The presence of .NO during irradiation of RB and NADH introduced a lag time into the kinetics of RB photobleaching. The length of this lag time was proportional to the concentration of .NO. A similar lag time, which was also dependent on the .NO concentration, was observed in the kinetics of formation of RB.-. The three-line electron spin resonance (ESR) spectrum of RB.-, with an intensity ratio 1:2:1, was obtained during irradiation of RB and NADH under anaerobic conditions. .NO introduced a concentration-dependent lag time into the kinetics of the appearance of this ESR signal. We propose that .NO oxidizes RB.- to regenerate RB and thus inhibit photobleaching until .NO is consumed. This reaction predicts the formation of NO-, the one-electron reduced form of .NO. Nitrous oxide, a characteristic dimerization product of NO-, was detected by gas chromatography. This evidence indicates the occurrence of a Type I mechanism between photoactivated RB and .NO.

Author List

Singh RJ, Hogg N, Kalyanaraman B

Authors

Neil Hogg PhD Associate Dean, Professor in the Biophysics department at Medical College of Wisconsin
Balaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Anions
Ascorbic Acid
Electron Spin Resonance Spectroscopy
Free Radicals
Glutathione
Kinetics
Light
Models, Chemical
NAD
Nitric Oxide
Nitrogen Oxides
Nitrous Oxide
Oxidation-Reduction
Photochemistry
Rose Bengal
Spectrophotometry