Committed step
In enzymology, the committed step (also known as the first committed step) is an effectively irreversible enzymatic reaction that occurs at a branch point during the biosynthesis of some molecules. As the name implies, after this step, the molecules are "committed" to the pathway and will ultimately end up in the pathway's final product. The first committed step should not be confused with the rate-determining step, which is the slowest step in a reaction or pathway. However, it is sometimes the case that the first committed step is in fact the rate-determining step as well. Regulation Metabolic pathways require tight regulation so that the proper compounds get produced in the proper amounts. Often, the first committed step is regulated by processes such as feedback inhibition and activation. Such regulation ensures that pathway intermediates do not accumulate, a situation that can be wasteful or even harmful to the cell. Examples of enzymes that catalyze the first committed steps of metabolic pathways Phosphofructokinase 1 catalyzes the first committed step of glycolysis. LpxC catalyzes the first committed step of lipid A biosynthesis. 8-amino-7-oxononanoate synthase catalyzes the first committed step in plant biotin synthesis. MurA catalyzes the first committed step of peptidoglycan biosynthesis. Aspartate