monophosphates

Monophosphates are compounds that contain a single phosphate group (PO4) attached to a molecule. They occur broadly as organophosphates—phosphate esters such as glycerol phosphate, glucose-1-phosphate, and other sugar phosphates—and as nucleoside monophosphates such as AMP, CMP, GMP, and UMP, which are the building blocks of RNA and DNA precursors. In aqueous solution, phosphate can exist in several protonation states, including dihydrogen phosphate (H2PO4−) and hydrogen phosphate (HPO4^2−); these species are typically referred to by their salts rather than as monophosphates.

In biochemistry and cell biology, monophosphates are key intermediates. Nucleoside monophosphates are phosphorylated to form diphosphates and triphosphates by kinases, enabling nucleotide synthesis and energy-related processes. Monophosphate esters participate in metabolic pathways as activated carriers or structural units, and some are converted to DNA and RNA nucleotides during replication and transcription.

Industrial and dietary uses include monophosphate salts, such as monosodium phosphate and monocalcium phosphate, which function as food additives, buffering agents, and leavening agents, and as components in fertilizers and water treatment.

Compared with diphosphates and triphosphates, monophosphates are distinct in containing a single phosphate moiety; many reactions involve further phosphorylation to higher-energy phosphate donors. The term encompasses diverse compounds from simple organophosphate esters to biologically essential nucleotide monophosphates.