The cycle Step 1. Oxidation of fuel molecules to acetyl CoA A major source of energy is glucose which is converted by glycolysis into pyruvate. Pyruvate dehydrogenase(a complex of three enzymes and five coenzymes)then oxidizes the pyruvate(using NAD which is reduced to NADH) to form acetyl CoA and Co. since the reaction involves both an oxidation and a loss of CO2, the process is called oxidative decarboxylationThe cycle • Step 1 .Oxidation of fuel molecules to acetyl CoA • A major source of energy is glucose which is converted by glycolysis into pyruvate. Pyruvate dehydrogenase (a complex of three enzymes and five coenzymes ) then oxidizes the pyruvate (using NAD+ which is reduced to NADH ) to form acetyl CoA and CO2 since the reaction involves both an oxidation and a loss of CO2 , the process is called oxidative decarboxylation