Final answer:
The rate-limiting enzymes that control glycolysis are hexokinase and phosphofructokinase, with pyruvate kinase also playing a significant regulatory role. These enzymes are crucial for ensuring that glycolysis is responsive to the energy needs of the cell.
Step-by-step explanation:
Glycolysis and Rate-Limiting Enzymes
The enzymes that control glycolysis, often referred to as rate-limiting enzymes, are hexokinase and phosphofructokinase. Hexokinase catalyzes the first step in glycolysis by phosphorylating glucose, which then traps the glucose inside the cell and prepares it for subsequent steps in the pathway. Phosphofructokinase is another crucial control point and is highly regulated by levels of ATP, ADP, AMP and citrate. The regulation of these enzymes ensures that glycolysis responds to the energy needs of the cell and does not proceed when energy is abundant or when intermediates of the pathway are needed for other purposes.
Another important regulatory enzyme in glycolysis is pyruvate kinase, which catalyzes the final step of the pathway. Pyruvate kinase's activity is influenced by various factors, including the levels of its substrate fructose-1,6-bisphosphate and allosteric effectors such as ATP. Its regulation ensures that the energy yield from glycolysis is closely matched to the cell's energy requirements.