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[[Ficheiro:Guanosintriphosphat protoniert.svg|thumb|right|Guanosín trifosfato.]]
O '''guanosín trifosfato''', '''trifosfato de guanosina''' ou '''guanosín-5'-trifosfato''' (abreviadamente '''GTP''') é un [[nucleótido]] de base [[purina|purínica]]. Está formado por un azucre [[ribosa]], unido por enlace N-glicosídico á [[base nitroxenada]] [[adenina]], que se establece entre o carbono 1 da ribosa e o nitróxeno 9 da base, e tres grupos [[fosfato]] unidos por [[enlace fosfodiéster]] co carbono 5' do azucre e por [[enlace anhidro]] entre si.
{{chembox
| verifiedrevid = 443850784
| ImageFile = Guanosintriphosphat protoniert.svg
| ImageSize = 200px
| IUPACName = [(2''R'',3''S'',4''R'',5''R'')-5-(2-amino-6-oxo-3''H''-purin-9-yl)-3,4- dihydroxyoxolan-2-yl]methyl (hydroxy-phosphonooxyphosphoryl) hydrogen phosphate
| OtherNames = guanosine triphosphate, 9-β-<small>D</small>-ribofuranosylguanine-5'-triphosphate, 9-β-<small>D</small>-ribofuranosyl-2-amino-6-oxo-purine-5'-triphosphate
| Section1 = {{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 6569
| InChI = 1/C10H16N5O14P3/c11-10-13-7-4(8(18)14-10)12-2-15(7)9-6(17)5(16)3(27-9)1-26-31(22,23)29-32(24,25)28-30(19,20)21/h2-3,5-6,9,16-17H,1H2,(H,22,23)(H,24,25)(H2,19,20,21)(H3,11,13,14,18)/t3-,5-,6-,9-/m1/s1
| InChIKey = XKMLYUALXHKNFT-UUOKFMHZBF
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C10H16N5O14P3/c11-10-13-7-4(8(18)14-10)12-2-15(7)9-6(17)5(16)3(27-9)1-26-31(22,23)29-32(24,25)28-30(19,20)21/h2-3,5-6,9,16-17H,1H2,(H,22,23)(H,24,25)(H2,19,20,21)(H3,11,13,14,18)/t3-,5-,6-,9-/m1/s1
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = XKMLYUALXHKNFT-UUOKFMHZSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 86-01-1
| PubChem = 6830
| IUPHAR_ligand = 1742
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 15996
| SMILES = c1nc2c(n1[C@H]3[C@@H]([C@@H]([C@H](O3)CO[P@@](=O)(O)O[P@](=O)(O)OP(=O)(O)O)O)O)[nH]c(nc2=O)N
| MeSHName = Guanosine+triphosphate
}}
| Section2 = {{Chembox Properties
| C=10|H=16|N=5|O=14|P=3
| Appearance =
| Density =
| MeltingPt =
| BoilingPt =
}}
| Section3 = {{Chembox Hazards
| Solubility =
| MainHazards =
| FlashPt =
| Autoignition =
}}
}}
Os enlaces entre os seus fosfatos poden liberar moita enerxía cando rompen, polo que exerce un papel como fonte de enerxía libre e activador de substratos en moitas reaccións metabólicas, pero, a diferenza do ATP, actúa en reaccións máis específicas. Úsase como fuonte de enrxía na síntese proteica.
'''Guanosine-5'-triphosphate''' ('''GTP''') is a [[purine]] [[nucleotide]]. It can act as a substrate for the synthesis of [[RNA]] during the [[transcription (genetics)|transcription]] process. Its structure is similar to that of the [[guanine]] [[nucleobase]], the only difference being that nucleotides like GTP have a [[ribose]] sugar and three [[phosphate]]s, with the nucleobase attached to the 1' and the triphosphate moiety attached to the 5' carbons of the ribose.
O GTP é moi importante na [[transdución de sinais]] na célula, especialmente coas [[proteína G|proteínas G]], en procesos nos que intervén un segundo mensaxeiro nos que se converte en [[GDP]] (guanosín difosfato) pola acción dunha [[GTPase]].
It also has the role of a source of energy or an activator of substrates in metabolic reactions, like that of [[adenosine triphosphate|ATP]], but more specific. It is used as a source of energy for [[protein biosynthesis|protein synthesis]].
GTP is essential to [[signal transduction]], particularly with [[G-proteins]], in second-messenger mechanisms where it is converted to [[Guanosine diphosphate|GDP]] (guanosine diphosphate) through the action of [[GTPase]]s.
===Transferencia de enerxía===
===Energy Transfer===
GTP is involved in energy transfer within the cell. For instance, a GTP molecule is generated by one of the enzymes in the [[citric acid cycle]]. This is tantamount to the generation of one molecule of [[Adenosine triphosphate|ATP]], since GTP is readily converted to ATP.<ref name=[[Stryer]]>{{cite book |last= Berg |first=JM |coauthors= JL Tymoczko, L Stryer |title= Biochemistry|edition=5th |pages =476|publisher= WH Freeman and Company |year=2002 |isbn= 0-7167-4684-0}}</ref>
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