57 Journal of Cell and Molecular Biology 5: 57-62, 2006. Haliç University, Printed in Turkey. The effect of magnetic field on the activity of superoxide dismutase Nihal Büyükuslu, Özge Çelik and Çimen Atak* Haliç University, Faculty of Arts and Sciences, Department of Molecular Biology and Genetics, F›nd›kzade 34280, ‹stanbul-Turkey (* author for correspondence) Received 6 December 2005; Accepted 20 December 2005 Abstract The effects of magnetic field on superoxide dismutase activity were investigated. All living systems are affected by magnetic field and electromagnetic field in a way of their response systems. Since magnetic field has an impact on biochemical reactions that involve more than one unpaired electron, in our study SOD activity, one of the enzyme responsible for antioxidant system, was measured under magnetic fields using an apparatus explained at material methods. There has been a significant increase of SOD activity when passed 0, 1, 9 and 15 times at 2.9-4.6 mT magnetic field density for 0, 2.2, 19.8 and 33.0 seconds respectively. Key words: Superoxide dismutase, magnetic field, enzyme activity Manyetik alan›n süperoksit dismutaz aktivitesi üzerine etkisi Özet Superoksit dismutaz aktivitesi üzerine manyetik alan etkileri araflt›r›lm›flt›r. Bütün yaflayan sistemler, yan›t sistemlerine ba¤l› olarak elektrik ve manyetik alan ve elektromanyetik alandan etkilenirler. Manyetik alan, ortaklamam›fl elektron içeren biyokimyasal reaksiyonlar üzerinde etkili oldu¤undan, çal›flmam›zda, antioksidan sistemlerinden biri olan, SOD aktivitesi manyetik alan alt›nda ölçüldü. 2.9-4.6 mT da 0, 1, 9 ve 15 kez, s›ras›yla 0, 2.2, 19.8 ve 33.0 sn lik zamanlarda geçirildi¤inde SOD aktivitesinde önemli bir art›fl tespit edildi. Anahtar sözcükler: Süperoksit dismutaz, manyetik alan, enzim aktivitesi Introduction Superoxide dismutase (SOD) is one of the most important antioxidant enzymes and present in all oxygen-metabolizing cells. Therefore, research on SOD activity will be important for the understanding of antioxidant mechanisms of life. Superoxide dismutases are divided in four classes considering their metal content. One of the classes is Cu 2+ -Zn 2+ enzyme which is found in the cytosol of eukaryotes, in chloroplasts, and in the periplasm of some prokaryotes; the second class is Mn 3+ protein which is found in bacteria, archaea, mitochondria and chloroplasts whereas Fe 3+ enzyme is present in both aerobic and anaerobic bacteria, archaea and plants (Parker and Blake, 1988; Beyer et al., 1989; Grace, 1990). The fourth type Ni-SOD has been discovered in several Streptomyces species (Cannio et al., 2000). In this study we used Cu-Zn superoxide dismutase that consists of two subunits of identical molecular weight joined by a disulfide bond with total molecular weight of 32,500 (Keele et al., 1971). In Cu-Zn SOD there are two Cu 2+ and two Zn 2+ atoms per molecule (Bannister et al., 1971). According to Forman and Fridovich (1973) Zn 2+ has a structural, stabilizing role, while Cu 2+ is directly involved in the catalytic activity. The mechanism of action of Cu-Zn SOD involves alternate reduction and reoxidation of the Cu 2+ at the active site