Glucuronidation (WP1276)

Rattus norvegicus

Metabolism of xenobiotic compounds consists of phase I and a phase II biotransformation reactions, being compound modification and conjugation reactions respectively. In phase I biotransformation, the compound is modificated via oxidation, reduction, hydrolysis, or other minor reactions, to reveal a reactive group to which a conjugation molecule can react to. In phase II, a small conjugation molecule reacts with the phase I modified molecule, producing a much more water-soluble molecule that can be excreted more easily. Glucuronidation is a phase II biotransformation reaction in which glucuronide acts as a conjugation molecule and binds to a substrate via the catalysis of glucuronosyltransferases. First, in a series of reactions the cosubstrate uridine diphosphate glucuronic acid (UDPGA) is formed. The glucuronosyltransferases (UGTs) then catalyze the transfer of glucuronic acid from UDPGA to a substrate resulting in a glucuronidated substrate and leaving uridine 5'-diphosphate. UGTs are a very broad and divers group of enzymes and count as the most significant group of conjugation enzymes in xenobiotic metabolism, qualitatively because glucuronic acid can be coupled to a large diversity of functional groups and quantitatively because of the large and divers number of substrates that are formed.


Christine Chichester and Egon Willighagen


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Rattus norvegicus



Pathway Ontology

glucuronidation conjugation pathway


Label Type Compact URI Comment
Adenosine 3',5'-diphosphate Metabolite hmdb:HMDB0000061
2H+ Metabolite chebi:15378
Glucose 6-phosphate Metabolite hmdb:HMDB0001401
Uridine 5'-diphosphate Metabolite hmdb:HMDB0000295
NAD Metabolite hmdb:HMDB0000902
Water Metabolite hmdb:HMDB0002111
Adenosine triphosphate Metabolite hmdb:HMDB0000538
NADH Metabolite hmdb:HMDB0001487
Uridine diphosphate glucose Metabolite hmdb:HMDB0000286
Phosphate Metabolite hmdb:HMDB0001429
Glucose 1-phosphate Metabolite hmdb:HMDB0001586
Uridine diphosphate glucuronic acid Metabolite hmdb:HMDB0000935
Phosphate Metabolite hmdb:HMDB0001429
Uridine triphosphate Metabolite hmdb:HMDB0000285
D-Glucose Metabolite hmdb:HMDB0000122
Ugp2 GeneProduct ensembl:ENSRNOG00000008079
NP_001102242.1 GeneProduct ensembl:ENSRNOG00000009515
PGM5 GeneProduct ncbigene:679990
Pgm2 GeneProduct ensembl:ENSRNOG00000002185
HK1 GeneProduct ncbigene:25058
Ugdh GeneProduct ensembl:ENSRNOG00000002643
Pgm1 GeneProduct ensembl:ENSRNOG00000009889
UGT2B17 GeneProduct ncbigene:286954
Ugt1a5 GeneProduct ncbigene:574523
UGT1A8 GeneProduct ncbigene:301595
Ugt2a3 GeneProduct ncbigene:289533
Ugt1a6 GeneProduct ncbigene:113992
Ugt2b36 GeneProduct ncbigene:83808
Ugt2b17 GeneProduct ncbigene:286954
Ugt2b34 GeneProduct ncbigene:305264
Ugt1a3 GeneProduct ncbigene:396551
Ugt2a1 GeneProduct ncbigene:63867
Ugt1a1 GeneProduct ncbigene:24861
UGT1A9 GeneProduct ncbigene:396552
LOC286989 GeneProduct ncbigene:286989
Ugt1a2 GeneProduct ncbigene:396527


  1. The biochemistry of drug metabolism--an introduction: part 4. reactions of conjugation and their enzymes. Testa B, Krämer SD. Chem Biodivers. 2008 Nov;5(11):2171–336. PubMed Europe PMC Scholia
  2. Androgen-stimulated UDP-glucose dehydrogenase expression limits prostate androgen availability without impacting hyaluronan levels. Wei Q, Galbenus R, Raza A, Cerny RL, Simpson MA. Cancer Res. 2009 Mar 15;69(6):2332–9. PubMed Europe PMC Scholia