Isomerase is an enzyme that catalyzes the conversion of a molecule into one of its isomers, which are compounds with the same molecular formula but different structural arrangements. This process is essential in various biological pathways, as it helps in the rearrangement of atoms within a molecule, allowing for the formation of different functional groups or structures. Isomerases play a crucial role in metabolism, particularly in the breakdown and synthesis of carbohydrates, amino acids, and nucleotides. By facilitating these transformations, isomerases contribute to the overall efficiency of biochemical reactions, ensuring that cells can adapt to changing conditions and maintain homeostasis.