Step seven of glycolysis is the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate, which is catalyzed by the enzyme phosphoglycerate kinase. This step is considered reversible because it operates near equilibrium under physiological conditions.
The reaction can go in both directions depending on the concentration of reactants and products. If there is a high concentration of 1,3-bisphosphoglycerate and ADP, the reaction will proceed forward, producing more 3-phosphoglycerate and ATP. Conversely, if the concentrations shift, the reverse reaction can occur, which allows the system to maintain metabolic balance and respond to the cellular energy demands.
Moreover, the reversible nature of this step is crucial for regulating the glycolytic pathway, allowing the flow of metabolites to be adjusted based on the needs of the cell. This flexibility helps optimize energy production and substrate utilization in response to changing conditions.