Effects of some antibiotics on activity of glucose-6-phosphate dehydrogenase from human erythrocytes in vitro and effect of isepamicin sulfate on activities of antioxidant enzymes in rat erythrocytes

The purpose of this study was to investigate effects of some antibiotics on glucose-6-phosphate dehydrogenase (G6PD), antioxidant enzymes, and malondialdehyde (AIDA). Initially, for in vitro studies, G6PD was purified from human erythrocyte, 9811-fold in a yield of 42.4% by using ammonium sulfate precipitation and 2',5'ADP-Sepharose 4B affinity gel. The purified enzyme showed a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The effects of four different antibiotics (isepamicin sulfate, meropenem, chloramphenicol, and thiamphenicol glisinat hydrochloride) were investigated on the purified enzyme. K-i value and type of inhibition were determined by means of Lineweaver-Burk graphs and regression analysis graphs. Isepamicin sulfate inhibited the enzyme activity (I-50 value, 2.1 mM; K-i value, 1.7 mM), whereas thiamphenicol glisinat hydrochloride activated the G6PD dose dependently. Other drugs showed no inhibition and activation effect. In addition, the effects of isepamicin sulfate on the activities of G6PD, glutathione reductase (GR), superoxide dismutases (SOD), glutathione peroxidase (GPx), catalase (CAT), and glutathione S-transferase (GST) and MDA contentrations were examined in Sprague-Dawley rat erythrocytes in vivo. A marked alteration in the activities of these enzymes and MDA levels may be the result of oxidative stress in the rats receiving isepamicin sulfate.