Nucleoside metabolism involves the biochemical processes that break down and synthesize nucleosides, which are the building blocks of nucleic acids like DNA and RNA. Nucleosides consist of a nitrogenous base attached to a sugar molecule. The metabolism of nucleosides is crucial for cellular functions, including energy production and the regulation of genetic information. In the body, nucleosides can be salvaged from degraded nucleic acids or synthesized de novo. Enzymes such as nucleoside phosphorylases and nucleoside kinases play key roles in these pathways, converting nucleosides into nucleotides, which are essential for various cellular processes, including DNA replication and RNA transcription.