Effects of some antibiotics on enzyme activity of glucose-6-phosphate dehydrogenase from human erythrocytes

Inhibitory effects of some antibiotics on glucose-6-phosphate dehydrogenase from the erythrocytes of human have been investigated. For this purpose, a t the beginning, erythrocyte glucose-6-phosphate dehydrogenase was purified 13.654 times in a yield of 28% by using ammonium sulphate precipitation an d 2',5'-ADP Sepharose 4B affinity gel. Temperature of +4 degrees C was main tained during the purification process. Enzyme activity was determined with the Beutler method by using a spectrophotometer at 340 nm. This method was utilized for all kinetic studies. Sodium ceftizoxime, sodium ampicillin, s odium cefuroxime, sodium cefazolin, sodium cefoperazone, streptomycin sulph ate, gentamicin sulphate, and netilmicin sulphate were used as antibiotics. All the antibiotics indicated the inhibitory effects on the enzyme. K-i co nstants for glucose-6-phosphate dehydrogenase were found by means of Linewe aver-Burk graphs. While sodium cefoperazone, gentamicin sulphate, and netil micin sulphate showed competitive inhibition, the others displayed non-comp etitive inhibition. In addition, I-50 values of the antibiotics were determ ined by plotting activity percent vs [I]. In addition, in vivo studies were done for sodium sefuroxime in Sprague-Dawley type rats. It was found that G6PD in erythrocyte was more inhibited by the drug in 2.5 h. (C) 2000 Acade mic Press.