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''''''Uridin 5'-difosfo-glukuronosyltransferase'''''' ([[Uridin difosfat|UDP]]-glukuronosiltransferase, UGT)<ref>{{en}}{{cite web
'''Glusuronosiltransferase''' ({{lang-en|1-naphthol glucuronyltransferase; 1-naphthol-UDP-glucuronosyltransferase; 17β-hydroxysteroid UDP-glucuronosyltransferase; 3α-hydroxysteroid UDP-glucuronosyltransferase; 4-hydroxybiphenyl UDP-glucuronosyltransferase; 4-methylumbelliferone UDP-glucuronosyltransferase; 4-nitrophenol UDP-glucuronyltransferase; 4-nitrophenol UDPGT; 17-OH steroid UDPGT; 3-OH androgenic UDPGT; bilirubin uridine diphosphoglucuronyltransferase; bilirubin UDP-glucuronosyltransferase; bilirubin monoglucuronide glucuronyltransferase; bilirubin UDPGT; bilirubin glucuronyltransferase; ciramadol UDP-glucuronyltransferase; estriol UDP-glucuronosyltransferase; estrone UDP-glucuronosyltransferase; uridine diphosphoglucuronosyltransferase; uridine diphosphoglucuronate-bilirubin glucuronoside glucuronosyltransferase; uridine diphosphoglucuronate-bilirubin glucuronosyltransferase; uridine diphosphoglucuronate-estriol glucuronosyltransferase; uridine diphosphoglucuronate-estradiol glucuronosyltransferase; uridine diphosphoglucuronate-4-hydroxybiphenyl glucuronosyltransferase; uridine diphosphoglucuronate-1,2-diacylglycerol glucuronosyltransferase; uridine diphosphoglucuronate-estriol 16α-glucuronosyltransferase; uridine diphosphoglucuronosyltransferase; GT; morphine glucuronyltransferase; p-hydroxybiphenyl UDP glucuronyltransferase; p-nitrophenol UDP-glucuronosyltransferase; p-nitrophenol UDP-glucuronyltransferase; p-nitrophenylglucuronosyltransferase; p-phenylphenol glucuronyltransferase; phenyl-UDP-glucuronosyltransferase; PNP-UDPGT; UDP glucuronate-estradiol-glucuronosyltransferase; UDP glucuronosyltransferase; UDP glucuronate-estriol glucuronosyltransferase; UDP glucuronic acid transferase; UDP glucuronyltransferase; UDP-glucuronate-4-hydroxybiphenyl glucuronosyltransferase; UDP-glucuronate-bilirubin glucuronyltransferase; UDP-glucuronosyltransferase; UDP-glucuronyltransferase; UDPGA transferase; UDPGA-glucuronyltransferase; UDPGT; uridine diphosphoglucuronyltransferase; uridine diphosphoglucuronate-bilirubin glucuronosyltransferase; uridine diphosphate glucuronyltransferase; uridine 5'-diphosphoglucuronyltransferase; uridine diphosphoglucuronosyltransferase, UDP-glucuronate β-D-glucuronosyltransferase (acceptor-unspecific), UGT, EC 2.4.1.17}})<ref>{{en}}{{cite web
| url = http://www.chem.qmul.ac.uk/iubmb/enzyme/EC2/4/1/17.html
| title = EC 2.4.1.17
| accessdate = 2011-05-18
| work = Queen Mary University of London
}}</ref> adalah [[enzim]] [[fase]] II yang meng[[katalis]] reaksi [[konjugasi]] [[gugus fungsional|gugus]] [[glusuronilglukuronil]] dari [[asam glusuronat|''uridineuridin 5'-diphosphoglucuronicasam aciddifosfoglukuronat'']] ke berbagai [[substrat]] [[nukleofilik]] eksogenus dan endogenus untuk menghasilkan [[senyawa organik|senyawa]] [[glusuronidaglukuronida]] yang mempunyai kadar toksin lebih rendah dan lebih ''polar'' sehingga lebih mudah untuk di[[ekskresi]].<ref>{{en}}{{cite web
| url = http://jn.nutrition.org/content/137/4/890.full
| title = UGT1A1 Polymorphism Is Associated with Serum Bilirubin Concentrations in a Randomized, Controlled, Fruit and Vegetable Feeding Trial
}}</ref> khususnya senyawa [[karsinogen]]ik seperti [[fenolik]], [[hidrokarbon]] [[poliaromatik]], [[amina]] [[aromatik]].
Reaksi konjugasi UGT disebut reaksi [[glusuronidasiglukuronidasi]], yang biasa terjadi pada [[lintasan metabolisme|lintasan]] [[detoksifikasi]] dengan variasi enzim detoks lain seperti [[sitokrom P450]] dan [[glutathion]] S-[[transferase]]. Glusuronidasi mencegah terjadinya oksidasi terus-menerus pada ''electrophile'' yang lebih lanjut dapat menimbulkan reaksi kimiawi antara [[toksin]] dengan [[DNA]], [[RNA]] dan [[protein]] [[inti sel|inti]] lainnya.<ref>{{en}}{{cite web
| url = http://www.ncbi.nlm.nih.gov/pubmed/1914494
| title = Roles of UDP-glucuronosyltransferases in chemical carcinogenesis
| accessdate = 2011-05-18
| work = Department of Biology and Center for Cancer Research, Massachusetts Institute of Technology, Department of Epidemiology and Lineberger Comprehensive Cancer Center, University of North Carolina, School of Public Health, Queensland University of Technology; Chantal Guillemette, Robert C. Millikan, Beth Newman, dan David E. Housman
}}</ref> dan senyawa endogenus lain seperti bilirubin, steroid seks, [[estriol]] dan 17ß-estradiol, serta senyawa xenobiotik yang berasal dari asupan makanan seperti fenol, ''[[anthraquinonesanthrakuinon]]'', dan [[flavon]]. Senyawa karsinogen dari asupan makanan seperti ''[[2-amino-1-methylmetil-6-phenylimidaxofenilimidakso(4,5-b)pyridinepiridin]]'' dan [[benzoapirena]] juga ikut terkonjugasi. Aktivitas UGT-1A1 terutama meningkat pada [[kanker payudara]] dan [[hepatokarsinoma]].
[[Ekspresi gen|Ekspresi]] UGT-1A1 dapat diinduksi oleh senyawa organik yang terdapat pada [[sayur|sayur-mayur]]. [[Sulforafana]], produk hasil reaksi [[hidrolisis]] dari senyawa [[glukorafanin]] yang terdapat pada sayur [[Brasicca]], dapat meningkatkan [[transkripsi]] [[mRNA]] UGT-1A1 dan kandungan protein seluler pada HepG2, HT29, dan Caco-2.
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