<p>Glucose-6-phosphate dehydrogenase (G6PD) plays a key function in various biochemical processes as they produce reducing power of the cell. Thus, metabolic reprogramming of nicotinamide adenine dinucleotide homeostasis is reported to be an important step in cancer progression as well as in combinational therapeutic approaches. In this study, the effects of the antibiotics, furosemide, cefazolin, cefuroxime, gentamicin and clindamycin on rat erythrocyte G6PD enzyme was studied in <i>in vitro</i> conditions. The enzyme was purified by 2', 5'-adenosine diphosphate Sepharose 4B affinity chromatography in a single purification step with 1825 fold and 83.7% yield. The specific activity of the enzyme was 29.2 EU/mg proteins. The inhibition studies of these antibiotics were carried out on the enzyme revealing that gentamicin, clindamycin and furosemide inhibited the activity of the G6PD with an IC<sub>50</sub> of 1.75, 34.65 and 0.526 mM, respectively with K<sub>i</sub> of 0.7, 39.8 and 0.860 mM, respectively. All inhibition types were analyzed by Lineweaver-Burk diagram showing noncompetitive inhibition for furosemide and gentamicin while clindamycin inhibited the activity competitively. On the other hand, cefazolin and cefuroxime increased the activity of the enzyme.</p
