Guanosine triphosphate (GTP) is also known as guanosine-5'-triphosphate, G3P, and 9-ß-D-ribofuranosylguanine-5'-triphosphate. GTP is a purine nucleotide that is incorporated into the growing RNA chain during RNA synthesis, and used as a source of energy for protein synthesis.
GTP is also essential to signal transduction, where it is converted to GDP through the action of GTPases.
Energy transfer
GTP is involved in energy transfer within the cell. For instance, one GTP molecule is generated for every turn of the citric acid cycle. This is tantamount to the generation of one molecule of ATP since GTP is readilty converted to ATP.