Figure 1

Cellular glycolysis and oxidative phosphorylation. Glycolysis and oxidative phosphorylation are two major energy-yielding pathways. Glucose is converted into pyruvate in the glycolytic pathway. The fate of pyruvate is dependent on many factors, of which oxygen availability is important. In anaerobic conditions, pyruvate is converted into lactate by LDH-A in the cytoplasm. LDH-B converts lactate into pyruvate. ECAR is a measure of lactic acid levels, generated by anaerobic glycolysis. In aerobic conditions, pyruvate enters the citric acid cycle via the PDH complex, and is catabolized by oxidative phosphorylation, producing electrons that pass through the electron transport chain to pump protons across the inner mitochondrial membrane. Protons are accumulated in the mitochondrial intermembrane space, and generates an electrochemical gradient across the inner mitochondrial membrane that is used for ATP production by ATP synthase (complex Ѵ). OCR is a measure of oxygen utilization in cells and is an indicator of mitochondrial function. The conversion of glucose into lactate generates 2 ATP per glucose molecule as compared to 36 ATP per glucose molecule when the oxidative phosphorylation is used. 2-NBDG; 2-[N-(7-nitobenz-2-oxa-1,3-diazol-4-yl)-amino]-2-deoxy-D glucose. 2-DG; 2-deoxyglucose. Glut; glucose transporters. G-6-P; glucose-6-phosphate. F-6-P; fructose-6-phosphate. PFKFB3; 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3. F-2,6-BP; fructose-2,6-biphosphate. F-1,6-P; fructose-1,6-phosphate. PEP; phosphoenolpyruvate. LDH-A; lactate dehydrogenase A. LDH-B; lactate dehydrogenase B. PDH; pyruvate dehydrogenase. NADH; nicotinamide adenine dinucleotide. FADH₂; Flavin adenine dinucleotide. H⁺; proton. OxPhos; oxidative phosphorylation. BPTES; bis-2-2(5-phenylacetamido-1,3,4-thiadiazol-2-yl) ethyl sulfide. POCA; sodium 2-[5-(4-chlorophenyl)pentyl]-oxirane-2-carboxylate. ECAR; extracellular acidification rates. OCR; oxygen consumption rates. ADP; adenosine 5’-diphosphate. ATP; adenosine 5’-triphosphate. FCCP; carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone.