Evidence for superoxide generation from the autoxidation of the favism-inducing aglycone divicine

• Published in: Biochimica et biophysica acta Vol. 926; no. 3; pp. 369 - 372
• Main Authors: Musci, Giovanni, Mavelli, Irene, Rotilio, Giuseppe
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 07.12.1987; Elsevier; North-Holland
• Subjects: Aglycone; Analytical, structural and metabolic biochemistry; Autoxidation; Biological and medical sciences; Cyclic N-Oxides; Divicine; Electron Spin Resonance Spectroscopy; Enzymes and enzyme inhibitors; Favism; Fundamental and applied biological sciences. Psychology; Oxidation-Reduction; Oxidoreductases; Pentetic Acid; Pyrimidinones - metabolism; Superoxide production; Superoxides - metabolism; Autoxidation; DETAPAC; Divicine; Superoxide production; Aglycone; DMPO; Favism; TEMPO; Enzyme; Vicia faba; Glucose dehydrogenase; Hyperoxides; Reduction; Leguminosae; Dicotyledones; Angiospermae; Spermatophyta; Kinetics; EPR spectrum
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/0304-4165(87)90224-8

The formation of the superoxide anion radical (O 2 −) during the autoxidation of divicine, an unstable aglycone involved in the hemolytic anemia occuring in favism, has been demonstrated by EPR with two different procedures. In the first case (chemical method) an O 2 −-mediated reduction of a nitroxide by cysteine was shown to occur when divicine was allowed to cycle between the oxidized and the reduced form. In the second case (enzymatic method) the specific reaction between superoxide and superoxide dismutase was used as superoxide detector. It was shown that the enzyme attained a steady-state condition when mixed with divicine in the presence of air, as monitored by EPR evaluation of the oxidation state of the catalytic copper: this result is a direct, specific indicator of an O 2 − flux.