Glycolysis, the initial stage of glucose metabolism, takes place in the cytosol and does not involve molecular O2. It produces a small amount of ATP and the three-carbon compound pyruvate A set of 10 enzymes catalyze the reactions, constituting the glycolytic pathway, that degrade one molecule of glucose to two molecules of pyruvate. A set of 12 oxidation and reduction reactions take place in the conversion of glucose to two pyruvates.