 ATP is used as a substrate in signal transduction pathways by kinases that phosphorylate proteins and lipids . It is also used by adenylate cyclase , which uses ATP to produce the second messenger molecule cyclic AMP . The ratio between ATP and AMP is used as a way for a cell to sense how much energy is available and control the metabolic pathways that produce and consume ATP . Apart from its roles in signaling and energy metabolism , ATP is also incorporated into nucleic acids by polymerases in the process of transcription . ATP is the neurotransmitter believed to signal the sense of taste . 
