title: Semiquinone anion radicals of catechol(amine)s, catechol estrogens, and their metal ion complexes.
abstract: The characterization and identification of semiquinone radicals from catechol(amine)s and catechol estrogens by electron spin resonance spectroscopy is addressed. The use of diamagnetic metal ions, especially Mg2+ and Zn2+ ions, to detect transient semiquinone radicals in biological systems and to monitor their reactions, is discussed. A brief account of the identification and reactions of quinones is also presented.
mesh_terms: D000818:Animals; D016227:Benzoquinones; D002395:Catecholamines; D002396:Catechols; D055598:Chemical Phenomena; D002621:Chemistry; D004578:Electron Spin Resonance Spectroscopy; D002393:Estrogens, Catechol; D005609:Free Radicals; D007700:Kinetics; D008670:Metals; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D010777:Photochemistry; D011809:Quinones / Q000633:toxicity; D013329:Structure-Activity Relationship
chemical_list: D016227:Benzoquinones; D002395:Catecholamines; D002396:Catechols; D002393:Estrogens, Catechol; D005609:Free Radicals; D008670:Metals; D011809:Quinones; C025232:semiquinone radicals; D010088:Oxidoreductases