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| Names | |
|---|---|
| IUPAC name Guanosine 5′-(tetrahydrogen triphosphate) | |
| Systematic IUPAC name O1-{[(2R,3S,4R,5R)-5-(2-Amino-6-oxo-1,6-dihydro-9H-purin-9-yl)-3,4-dihydroxyoxolan-2-yl]methyl} tetrahydrogen triphosphate | |
| Other names guanosine triphosphate, 9-β-D-ribofuranosylguanine-5'-triphosphate, 9-β-D-ribofuranosyl-2-amino-6-oxo-purine-5'-triphosphate | |
| Identifiers | |
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3D model (JSmol) | |
| ChEBI | |
| ChemSpider |
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| ECHA InfoCard | 100.001.498 |
| KEGG |
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| MeSH | Guanosine+triphosphate |
| UNII | |
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| Properties | |
| C10H16N5O14P3 | |
| Molar mass | 523.180 g·mol−1 |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Guanosine-5'-triphosphate (GTP) is apurinenucleoside triphosphate. It is one of the building blocks needed for the synthesis ofRNA during thetranscription process. Its structure is similar to that of theguanosinenucleoside, the only difference being thatnucleotides like GTP havephosphates on theirribose sugar. GTP has theguaninenucleobase attached to the 1' carbon of the ribose and it has the triphosphate moiety attached to ribose's 5' carbon.
It also has roles as a source of energy and as an activator ofsubstrates in metabolic reactions, similar to the roles ofATP, but it is more specific. It is used as a source of energy forprotein synthesis andgluconeogenesis.
GTP is essential tosignal transduction, in particular withG-proteins, in second-messenger mechanisms where it is converted toguanosine diphosphate (GDP) through the action ofGTPases.
GTP is involved in energy transfer within the cell. For instance, a GTP molecule is generated by one of the enzymes in thecitric acid cycle. This is tantamount to the generation of one molecule ofATP, since GTP is readily converted to ATP withnucleoside-diphosphate kinase (NDK).[1]
During the elongation stage oftranslation, GTP is used as an energy source for the binding of a new amino-boundtRNA to the A site of theribosome. GTP is also used as an energy source for the translocation of the ribosome towards the 3' end of themRNA.[2]
Duringmicrotubule polymerization, each heterodimer formed by an alpha and a betatubulin molecule carries two GTP molecules, and the GTP is hydrolyzed to GDP when the tubulin dimers are added to the plus end of the growing microtubule. Such GTP hydrolysis is not mandatory for microtubule formation, but it appears that only GDP-bound tubulin molecules are able to depolymerize. Thus, a GTP-bound tubulin serves as a cap at the tip of a microtubule to protect it from depolymerization; and, once the GTP is hydrolyzed, the microtubule begins to depolymerize and shrink rapidly.[3]
The translocation of proteins into themitochondrial matrix involves the interactions of both GTP and ATP. The importing of these proteins plays an important role in several pathways regulated within mitochondria,[4] such as convertingoxaloacetate tophosphoenolpyruvate (PEP) in gluconeogenesis.[citation needed]
GTP, in combination withribulose 5-phosphate, are the precursor compounds for the synthesis ofriboflavin (vitamin B2).[5]
In the cell, GTP is synthesized through many processes including:
