Formation of methyl radicals during the catalase-mediated oxidation of formaldehyde hydrazone.
It has been suggested that formaldehyde hydrazone, a condensation product of hydrazine with formaldehyde, plays an important role in hydrazine-promoted DNA methylation in vivo. The present study demonstrated by spin-trapping experiments with 5,5-dimethyl-1-pyrroline-N-oxide and tert-nitrosobutane that catalase-mediated oxidation of formaldehyde hydrazone generates methyl radicals. Both the use of two spin-traps and parallel studies of oxygen consumption were important for excluding possible artefacts of spin-trapping experiments with tert-nitrosobutane. Hydrazine was also oxidized by catalase but only hydroxyl radicals were detected. Metabolic activation of formaldehyde hydrazone to methyl radicals may be of importance in regard to hydrazine-mediated toxicity and carcinogenicity.
Gomes
L F
LF
School of Pharmaceutical Sciences, Universidade de São Paulo, Brazil.
Augusto
O
O
D002374:Catalase / Q000494:pharmacology*; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy; D005557:Formaldehyde / Q000031:analogs & derivatives* / Q000378:metabolism; D005609:Free Radicals; D006835:Hydrazones / Q000378:metabolism*; D010084:Oxidation-Reduction
D003497:Cyclic N-Oxides; D005609:Free Radicals; D006835:Hydrazones; D005557:Formaldehyde; C054526:formaldehyde hydrazone; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D002374:Catalase