Cytidine deaminase is an enzyme that plays a crucial role in the metabolism of nucleotides, specifically by converting cytidine into uridine. This process involves the removal of an amino group from cytidine, which is essential for the proper functioning of various biological processes, including RNA synthesis and the regulation of nucleotide pools in cells. In addition to its metabolic functions, cytidine deaminase is also important in the context of pharmacology. It can influence the effectiveness of certain antiviral and anticancer drugs by altering their chemical structure, which can affect how these medications are processed in the body. Understanding this enzyme is vital for developing more effective treatments.