The enzyme that catalyzes the conversion of glucose and oxygen into energy is called pyruvate kinase, primarily in the context of glycolysis. During glycolysis, glucose is broken down into pyruvate, generating ATP and NADH, essential for energy production. However, the process transitions to the Krebs cycle (or citric acid cycle) in the presence of oxygen, further breaking down the products to produce additional ATP. Enzymes like pyruvate kinase help regulate these pathways, ensuring efficient energy generation for cellular processes.