The end product of glycolysis, pyruvic acid is converted to acetyl-CoA by the process of oxidative decarboxylation in presence of pyruvate dehydrogenase enzyme. During alcoholic fermentation, pyruvic acid is first converted to acetaldehyde in presence of enzyme pyruvate decarboxylase. The acetaldehyde is then converted into ethyl alcohol by enzyme dehydrogenase. During Krebs cycle, oxalosuccinate undergoes decarboxylation in the presence of oxalosuccinate decarboxylase to form alpha-ketoglutarate.Thus decarboxylation occurs after glycolysis and is not a part of glycolysis.