Stereoselective Glucuronidation of 5-(4′-Hydroxyphenyl)-5-phenylhydantoin by Human UDP-Glucuronosyltransferase (UGT) 1A1, UGT1A9, and UGT2B15: Effects of UGT-UGT Interactions

Nakajima, Miki; Yamanaka, Hidetoshi; Fujiwara, Ryoichi; Katoh, Miki; Yokoi, Tsuyoshi

doi:10.1124/dmd.107.015909

Cited by 32 publications

(24 citation statements)

References 21 publications

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“…Thereafter, the formation of various hetero-oligomers was described by means of several techniques. UGT1A1, UGT1A4, UGT1A6, and UGT1A9 have been found to form both homodimers and heterodimers (Fujiwara et al, 2007a,b;Nakajima et al, 2007). UGT1A1 was further demonstrated to interact with all members of the UGT1A family (Operaña and Tukey, 2007) and more recently with its i2 isoform, UGT1A1_i2 .…”

Section: Introductionmentioning

confidence: 99%

Alternatively Spliced Products of theUGT1AGene Interact with the Enzymatically Active Proteins to Inhibit Glucuronosyltransferase Activity In Vitro

Bellemare

Rouleau²,

Girard³

et al. 2010

Drug Metab Dispos

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ABSTRACT:UDP-glucuronosyltransferases (UGTs) are major mediators in conjugative metabolism. Current data suggest that UGTs, which are anchored in the endoplasmic reticulum membrane, can oligomerize with each other and/or with other metabolic enzymes, a process that may influence their enzymatic activities. We demonstrated previously that the UGT1A locus encodes previously unknown isoforms (denoted "i2"), by alternative usage of the terminal exon 5. Although i2 proteins lack transferase activity, we showed that knockdown of endogenous i2 levels enhanced cellular UGT1A-i1 activity. In this study, we explored the potential of multiple active UGT1A_i1 proteins (UGT1A1, UGT1A3, UGT1A4, UGT1A6, UGT1A7, UGT1A8, UGT1A9, and UGT1A10) to interact with all spliced i2s by coimmunoprecipitation. We further studied the functional consequences of coexpressing various combinations of spliced i1s and i2s from highly similar UGTs, namely UGT1A7, UGT1A8, and UGT1A9, based on expression profiles observed in human tissues. The i1 isoform of each UGT1A coimmunoprecipitated its respective i2 homolog as well as all other i2s, indicating that they can form heteromeric complexes. Functional data further support the fact that i2 splice species alter glucuronidation activity of i1s independently of the identity of the i2, although the degree of inhibition varied, suggesting that this phenomenon may occur in tissues expressing such combinations of splice forms. These results provide biochemical evidence to support the inhibitory effect of i2s on multiple active UGT1As, probably through formation of inactive heteromeric assemblies of i1s and inactive i2s. The relative abundance of active/inactive oligomeric complexes may thus determine transferase activity.

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Section: Introductionmentioning

confidence: 99%

Alternatively Spliced Products of theUGT1AGene Interact with the Enzymatically Active Proteins to Inhibit Glucuronosyltransferase Activity In Vitro

Bellemare

Rouleau²,

Girard³

et al. 2010

Drug Metab Dispos

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“…However, the binding affinities of substrates and catalytic efficiency are different between the four isoforms. Furthermore, some substrates are specific for certain UGT1A enzyme as follows: 5-(4Ј-hydroxyphenyl)-5-phenylhydantoin (UGT1A9) (Nakajima et al, 2007), phenylbutazone (UGT1A9) (Nishiyama et al, 2006), and 3-hydroxydesloratadine (UGT1A8) (Ghosal et al, 2004). By a sequence alignment analysis, 14 amino acid residues (Cys3, Arg42, Lys91, Ala92, Tyr106, Gly111, Tyr113, Asp115, Asn152, Leu173, Leu219, His221, Arg222, and Glu241) were found to be specific to UGT1A9 in comparison with UGT1A7, UGT1A8, and UGT1A10 ( Fig.…”

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confidence: 99%

Key Amino Acid Residues Responsible for the Differences in Substrate Specificity of Human UDP-Glucuronosyltransferase (UGT)1A9 and UGT1A8

Fujiwara¹,

Nakajima²,

Yamanaka³

et al. 2008

Drug Metab Dispos

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ABSTRACT:Human UDP-glucuronosyltransferase (UGT)1A9 is one of the major isoforms in liver and extrahepatic tissues, catalyzing the glucuronidation of a variety of drugs, dietary constituents, steroids, fatty acids, and bile acids. UGT1A9 shows high amino acid homology with UGT1A7, UGT1A8, and UGT1A10 with overlapping substrate specificity. However, the affinities for substrates are different among them. Amino acid alignment analysis revealed that 14 amino acids, Cys3, Arg42, Lys91, Ala92, Tyr106, Gly111, Tyr113, Asp115, Asn152, Leu173, Leu219, His221, Arg222, and Glu241, are unique to UGT1A9 compared with UGT1A7, UGT1A8, and UGT1A10. In this study, we constructed expression systems in human embryonic kidney 293 cells for seven mutants (

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“…Moreover, it has been reported that protein interaction between UGT and UGT or CYP in microsomes might cause changes in its enzyme activity and stereoselectivity. [21][22][23] The remaining enzyme activity might reflect this interaction. However, more research is needed to clarify the reason for this phenomenon.…”

Section: Discussionmentioning

confidence: 99%

Mutual Inhibition between Carvedilol Enantiomers during Racemate Glucuronidation Mediated by Human Liver and Intestinal Microsomes

Takekuma

Yagisawa

Sugawara

2012

Biological & Pharmaceutical Bulletin

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Carvedilol is administered orally as a racemic mixture of R( )-and S( )-enantiomers for treatment of angina pectoris, hypertension and chronic heart failure. We have reported that enzyme kinetic parameters for carvedilol glucuronidation by human liver microsomes (HLM) differed greatly depending on the substrate form, namely, racemic carvedilol and each enantiomer. These phenomena were thought to be caused by mutual inhibition between carvedilol enantiomers during racemate glucuronidation. The aim of this study was to clarify the mechanism of these phenomena in HLM and human intestinal microsomes (HIM) and its relevance to uridine 5′-diphosphate (UDP)-glucuronosyl transferase (UGT) 1A1, UGT2B4 and UGT2B7, which mainly metabolize carvedilol directly in phase II enzymes. HLM apparently preferred metabolizing (S)-carvedilol to (R)-carvedilol in the racemate, but true activities of HLM for both glucuronidation were approximately equal. By determination of the inhibitory effects of (S)-carvedilol on (R)-carvedilol glucuronidation and vice versa, it was shown that (R)-carvedilol glucuronidation was more easily inhibited than was (S)-carvedilol glucuronidation. UGT2B7 was responsible for (S)-carvedilol glucuronidation in HLM. Ratios of contribution to (R)-carvedilol glucuronidation were approximately equal among UGT1A1, UGT2B4 and UGT2B7. However, enzyme kinetic parameters were different between the two lots of HLM used in this study, depending on the contribution ratio of UGT2B4, in which (R)-glucuronidation was much more easily inhibited by (S)-carvedilol than was (S)-glucuronidation by (R)-carvedilol. Meanwhile, HIM preferred metabolizing (R)-carvedilol, and this tendency was not different between the kinds of substrate form.Key words carvedilol; uridine 5′-diphosphate-glucuronosyl transferase; glucuronidation; enantiomer; interaction Many drugs are administered orally as racemic mixtures because of the difficulty or high cost of selective synthesis of one optical isomer. A pair of enantiomers has the same physicochemical properties including melting point, boiling point and solubility without optical rotation. Both enantiomers have been thought to be recognized by the same enzyme in a metabolic process because of the similarity of their chemical structures. However, these enantiomers are recognized as different chemical compounds in vivo, and pharmacological and pharmacokinetic properties often differ between enantiomers. 1)In fact, there have been several reports of interaction between enantiomers via a metabolic enzyme. 2,3)Carvedilol is an antihypertensive and antianginal drug that favorably combines β-adrenergic blocking and vasodilating activities as a result of α-blocking action. 4,5) Carvedilol is also administered orally as a racemic mixture of R(+)-and S(−)-enantiomers.It is known that carvedilol is metabolized through multiple pathways. The enzymes that are involved in its metabolism are cytochrome P450 (CYP) 2D6 and CYP2C9 as phase I enzymes and uridine 5′-diphosphate (UDP)-glucuronosyl transferase (UGT) ...

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Stereoselective Glucuronidation of 5-(4′-Hydroxyphenyl)-5-phenylhydantoin by Human UDP-Glucuronosyltransferase (UGT) 1A1, UGT1A9, and UGT2B15: Effects of UGT-UGT Interactions

Abstract: and UGT1A9. However, the interaction did not alter the stereoselectivity. In conclusion, we found that 4-HPPH O-glucuronide formation in human liver microsomes is catalyzed by UGT1A1, UGT1A9, and UGT2B15 in a stereoselective manner, being modulated by interaction with other UGT1A isoforms.

Cited by 32 publications

References 21 publications

Alternatively Spliced Products of theUGT1AGene Interact with the Enzymatically Active Proteins to Inhibit Glucuronosyltransferase Activity In Vitro

Alternatively Spliced Products of theUGT1AGene Interact with the Enzymatically Active Proteins to Inhibit Glucuronosyltransferase Activity In Vitro

Key Amino Acid Residues Responsible for the Differences in Substrate Specificity of Human UDP-Glucuronosyltransferase (UGT)1A9 and UGT1A8

Mutual Inhibition between Carvedilol Enantiomers during Racemate Glucuronidation Mediated by Human Liver and Intestinal Microsomes

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