• Login
    View Item 
    •   Shocker Open Access Repository Home
    • Fairmount College of Liberal Arts and Sciences
    • Chemistry and Biochemistry
    • CHEM Faculty Scholarship
    • CHEM Faculty Publications
    • View Item
    •   Shocker Open Access Repository Home
    • Fairmount College of Liberal Arts and Sciences
    • Chemistry and Biochemistry
    • CHEM Faculty Scholarship
    • CHEM Faculty Publications
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    A slow-tight binding inhibitor of dopamine beta-monooxygenase: a transition state analogue for the product release step

    Date
    2002-10-15
    Author
    Dharmasena, Sanjeewa P.
    Wimalasena, D. Shyamali
    Wimalasena, Kandatege
    Metadata
    Show full item record
    Citation
    Biochemistry. 2002 Oct 15; 41(41): 12414-20.
    Abstract
    The steady-state kinetic data show that 3-hydroxy-4-phenylthiazole-2(3H)-thione (3H4PTT) is a potent tight-binding inhibitor for dopamine beta-monooxygenase (DbetaM) with a dissociation constant of 0.9 nM. Ackermann-Potter plots of the enzyme dependence of the inhibition revealed that the stoichiometry of the enzyme inhibition by 3H4PTT is 1:1. Pre-steady-state progress curves at varying inhibitor with fixed reductant and enzyme concentrations clearly show the slow binding behavior of the inhibitor. The observed kinetic behavior is consistent with the apparent direct formation of the tightly bound E x I* complex. The k(on) and k(off) for 3H4PTT which were determined under pre-steady-state conditions at variable inhibitor concentrations were found to be (1.85 +/- 0.07) x 10(6) M(-1) s(-1) and (1.9 +/- 0.6) x 10(-3) s(-1), respectively. The dissociation constant calculated from these rates was similar to that determined under steady-state conditions, confirming that 3H4PTT is a kinetically well-behaved inhibitor. The steady-state as well as pre-steady-state kinetic studies at variable DMPD concentrations show that the inhibition is competitive with respect to the reductant, demonstrating the exclusive interaction of 3H4PTT with the oxidized form of the enzyme. The kinetic behavior and the structural properties of 3H4PTT are consistent with the proposal that the E x 3H4PTT complex may mimic the transition state for the product (protonated) release step of the enzyme. Therefore, 3H4PTT could be used as a convenient probe to examine the properties of the E x P complex of the DbetaM reaction and also as an active site titrant for the oxidized enzyme.
    Description
    Full text of this article is not available in SOAR.
    URI
    http://hdl.handle.net/10057/4241
    Collections
    • CHEM Faculty Publications

    Browse

    All of Shocker Open Access RepositoryCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsBy TypeThis CollectionBy Issue DateAuthorsTitlesSubjectsBy Type

    My Account

    LoginRegister

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    DSpace software copyright © 2002-2022  DuraSpace
    DSpace Express is a service operated by 
    Atmire NV