Linked Life Data

16985098

Source:http://linkedlifedata.com/resource/pubmed/id/16985098

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2006-11-30
pubmed:abstractText
The uricosuric agent sulfinpyrazone (SFZ) is metabolized via C-glucuronidation, an uncommon metabolic pathway, in humans. The present study aimed to characterize SFZ glucuronidation by human liver microsomes (HLMs) and identify the hepatic forms of UDP-glucuronosyltransferase responsible for this pathway. Incubations of SFZ with HLMs formed a single glucuronide that was resistant to beta-glucuronidase and acid hydrolysis, consistent with formation of a C-glucuronide. Mass spectral analysis confirmed the identity of the metabolite as SFZ glucuronide (sulfinpyrazone beta-D-glucuronide; SFZG). SFZ C-glucuronidation by HLMs exhibited Michaelis-Menten kinetics, with mean (+/- S.D.) Km and Vmax values of 51 +/- 21 microM and 2.6 +/- 0.6 pmol/min . mg, respectively. Fifteen recombinant human UDP-glucuronosyltransferases (UGTs), expressed in HEK293 cells, were screened for their capacity to catalyze SFZ C-glucuronidation. Of the hepatically expressed enzymes, only UGT1A9 formed SFZG. UGTs 1A7 and 1A10, which are expressed in the gastrointestinal tract, also metabolized SFZ, but rates of metabolism were low compared with UGT1A9. SFZ glucuronidation by UGT1A9 exhibited "weak" negative cooperative kinetics, which was modeled by the Hill equation (S50 16 microM). The data indicate that UGT1A9 is the enzyme responsible for hepatic SFZ C-glucuronidation and that SFZ may be used as a substrate "probe" for UGT1A9 activity in HLMs.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0090-9556
pubmed:author
pubmed:issnType
Print
pubmed:volume
34
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1950-3
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Sulfinpyrazone C-glucuronidation is catalyzed selectively by human UDP-glucuronosyltransferase 1A9.
pubmed:affiliation
Department of Clinical Pharmacology, Flinders University and Flinders Medical Centre, Bedford Park, Adelaide, Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't