Pyruvate is then decarboxylated to acetaldehyde in a reaction involving the enzyme pyruvate decarboxylase. These liver enzymes included lactate dehydrogenase and glutamate pyruvate transaminase. Pyruvate is oxidized to acetyl-CoA and CO by the pyruvate dehydrogenase complex (PDC). Insulin stimulates the activity of pyruvate dehydrogenase phosphatase. It activates pyruvate dehydrogenase phosphatase which in turn activates the pyruvate dehydrogenase complex. These both serve to inhibit pyruvate dehydrogenase activity. Alanine and lactate are major gluconeogenic precursors that enter gluconeogenesis as pyruvate. The reaction catalyzed by pyruvate kinase is the final step of glycolysis. This protein kinase phosphorylates liver pyruvate kinase to deactivate it. There are two steps in the pyruvate kinase reaction in glycolysis. Lewisite is a suicide inhibitor of the E3 component of pyruvate dehydrogenase. Alanine and aspartate are synthesized by the transamination of pyruvate and oxaloacetate, respectively. Therefore, it is phosphorylation at site 1 that is responsible for pyruvate dehydrogenase deactivation. Serine is then converted to pyruvate by serine dehydratase. For example, serine dehydratase converts serine to pyruvate and ammonia.