Azidowarfarin photoaffinity probes of purified rat liver cytochrome P4501A1

Obach, R.; Spink, David C.; Chen, Norman; Kaminsky, Laurence S.

doi:10.1016/0003-9861(92)90160-x

Cited by 13 publications

(10 citation statements)

References 25 publications

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“…The 4'-, 6-and 7-azido derivatives of warfarin were gifts from Michael Fasco at the Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany. Synthesis and characterization of these phororeactive compounds are described by Obach et al (17). Synthesis of 4'-azido-warfarin-3 H-alcohol was carried by reducing 4'-azido-warfarin with 3 Hsodium borohydride (50 Ci/mmol; New England Nuclear, Boston, MA).…”

Section: Azido-warfarin Labelingmentioning

confidence: 99%

“…Labeling of calumenin by 4'-azido-warfarin-3 H-alcohol would suggest that calumenin is a warfarin binding protein. To find out whether calumenin indeed binds warfarin, as has been shown for fatty acid binding protein (35), cytochrome P450 (17), and albumin (25), we compared warfarin binding of r-calumenin with rat albumin (see Materials and Methods). As shown in Figure 9, the radioactivity associated with r-calumenin (r-calumenin ab.+ r-cal.)…”

Section: Calumenin Is Not a Warfarin Binding Proteinmentioning

confidence: 99%

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A molecular mechanism for genetic warfarin resistance in the rat

Wallin¹,

Hutson

Cain³

et al. 2001

FASEB j.

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Warfarin targets vitamin K 2,3-epoxide reductase (VKOR), the enzyme that produces reduced vitamin K, a required cofactor for g-carboxylation of vitamin K-dependent proteins. To identify VKOR, we used 4'-azido-warfarin-3H-alcohol as an affinity label. When added to a partially purified preparation of VKOR, two proteins were identified by mass spectrometry as calumenin and cytochrome B5. Rat calumenin was cloned and sequenced and the recombinant protein was produced. When added to an in vitro test system, the 47 kDa recombinant protein was found to inhibit VKOR activity and to protect the enzyme from warfarin inhibition. Calumenin was also shown to inhibit the overall activity of the complete vitamin K-dependent g-carboxylation system. The results were repeated in COS-1 cells overexpressing recombinant calumenin. By comparing calumenin mRNA levels in various tissues from normal rats and warfarin-resistant rats, only the livers from resistant rats were different from normal rats by showing increased levels. Partially purified VKOR from resistant and normal rat livers showed no differences in Km-values, specific activity, and sensitivity to warfarin. A novel model for genetic warfarin resistance in the rat is proposed, whereby the concentration of calumenin in liver determines resistance.

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Section: Azido-warfarin Labelingmentioning

confidence: 99%

Section: Calumenin Is Not a Warfarin Binding Proteinmentioning

confidence: 99%

A molecular mechanism for genetic warfarin resistance in the rat

Wallin¹,

Hutson

Cain³

et al. 2001

FASEB j.

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“…They also prepared various radiolabeled 3-substituted 4-hydroxycoumarin derivatives using commercially available [U- 14 C] phenol or [U- 3 H] in order to elucidate the binding photoaffinity. Compounds 62-64 serve as effective competitive inhibitors of the dicoumarol sensitive NADPH quinone reductase from rat liver [28,29]. …”

Section: Resultsmentioning

confidence: 99%

Synthetic Approaches and Biological Activities of 4-Hydroxycoumarin Derivatives

2009

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“…3-azido coumarins have been employed to generate strongly fluorescent 1, 2, 3-triazolyl coumarins [9] and recently this reaction has been used in non-destructive verification of PNA immobilization [10]. Azidowarfarins have been found to be useful photo affinity probes for rat liver cytochrome P450 [11]. Huisgen 1, 3-dipolar cycloadditions of 4-azidomethyl coumarins have lead to angularly oriented triazoles [12].…”

Section: Introductionmentioning

confidence: 99%