Biomaterial Database

Pulse-radiolytic investigations of catechols and catecholamines. II. Reactions of Tiron with oxygen radical species. 1979

W Bors, and M Saran, and C Michel

Transient spectra and kinetic data of Tiron (1,2-dihydroxybenzene-3,5-disulphonic acid) are reported, obtained after pulse-radiolytic oxidation by hydroxyl radicals (.OH), superoxide anions (O-2) or a combination of both oxygen radicals. The rate constant with .OH radicals was determined at 1.0.10(9) M-1.s-1. Contrary to a previous report (Greenstock, C.L. and Miller, R.W. (1975) Biochim. Biophys. Acta 396, 11--16), the rate constant with O-2 of 1.0.10(7) M-1.s-1 is lower by one order of magnitude; also the semiquinone absorbs at 300 nm rather than at 400 nm. The ratio of the rate constants with .OH and O-2 of 100 again demonstrates that any oxidation reaction by the latter radical is unspecific due to the more efficient reaction of .OH radicals, leading to the same products with catechol compounds.

UI	MeSH Term	Description	Entries
D010100	Oxygen	An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.	Dioxygen,Oxygen-16,Oxygen 16
D011675	Pulse Radiolysis	Use of a pulse of X-rays or fast electrons to generate free radicals for spectroscopic examination.	Radiolysis, Pulse
D002625	Chemistry, Organic	The study of the structure, preparation, properties, and reactions of carbon compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Organic Chemistry
D006878	Hydroxides	Inorganic compounds that contain the OH- group.
D001557	Benzenesulfonates	Organic salts and esters of benzenesulfonic acid.
D013057	Spectrum Analysis	The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Spectroscopy,Analysis, Spectrum,Spectrometry
D013481	Superoxides	Highly reactive compounds produced when oxygen is reduced by a single electron. In biological systems, they may be generated during the normal catalytic function of a number of enzymes and during the oxidation of hemoglobin to METHEMOGLOBIN. In living organisms, SUPEROXIDE DISMUTASE protects the cell from the deleterious effects of superoxides.	Superoxide Radical,Superoxide,Superoxide Anion
D014013	1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt	A colorimetric reagent for iron, manganese, titanium, molybdenum, and complexes of zirconium. (From Merck Index, 11th ed)	Tiron
D055601	Organic Chemistry Phenomena	The conformation, properties, reaction processes, and the properties of the reactions of organic carbon compounds.	Organic Chemistry Concepts,Organic Chemistry Processes,Organic Chemistry Phenomenon,Organic Chemistry Process,Chemistry Process, Organic,Chemistry Processes, Organic,Concept, Organic Chemistry,Concepts, Organic Chemistry,Organic Chemistry Concept,Phenomena, Organic Chemistry,Phenomenon, Organic Chemistry,Process, Organic Chemistry,Processes, Organic Chemistry