Abstract
It has been shown that carbon monoxide (CO) in low concentration may be an active biochemical and physiological regulator of cell function. The bases of CO toxicity and cell protection are not clearly understood. To provide insights into these mechanisms, we measured superoxide production by D. desulfuricans Bโ1388 incubated anaerobically in Postgate medium with or without 5% CO. D. desulfuricans Bโ1388 growing with CO in the gas phase produced more superoxide radicals then control cells growing in Ar. When the cells were pregrown with CO, NADH oxidase and peroxidase activities were increased. The increase in peroxidase activities of cells growing under CO (particularly NADH peroxidase) suggested that H~2~O~2~ was accumulated in cells. Superoxide dismutase (SOD) activity of cells decreased in exponential growth phase and increased in stationary phase. This may be due to CO concentration fall during CO oxidation by CO dehydrogenase. Altogether, our data suggest that superoxide production is a possible mechanism of CO toxicity. ยฉ 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:87โ91, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20011