• Login
    View Item 
    •   Home
    • Massey Documents by Type
    • Theses and Dissertations
    • View Item
    •   Home
    • Massey Documents by Type
    • Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Structural and mechanistic studies of sheep liver aldehyde dehydrogenase : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Chemistry at Massey University, New Zealand

    Icon
    View/Open Full Text
    02_whole.pdf (15.90Mb)
    01_front.pdf (796.0Kb)
    Export to EndNote
    Abstract
    Studies of NADH displacement in the presence of excess aldehyde dehydrogenase confirmed that a conformational change of the enzyme. NADH binary complex occurs as an essential step in the reaction mechanism. Modification of sulphydryl groups on the enzyme by the thiol reagent p-(chloromercuri) benzoate (PCMB) produced either activation or inhibition of the enzyme activity, depending upon the relative concentrations of PCMB and aldehyde dehydrogenase, the mixing conditions, and on the concentration of the aldehyde substrate. There was no direct evidence to support the widely held view that a sulphydryl group is catalytically essential. Studies of the pH dependence of the steady state and presteady state phases of the reaction indicated that there was a change in the rate limiting step as the pH was increased from acyl-enzyme hydrolysis at low pH to release of NADH from the enzyme at high pH. At low pH the release of NADH may occur before acyl-enzyme hydrolysis. Activation by high concentrations of propionaldehyde was shown to occur over the entire pH range (5 to 10). The reaction could be reversed when acid anhydrides were used to acylate the enzyme. NADH complex but the binding of the substrates for the reverse reaction did not appear to be ordered. Under these conditions other groups on the enzyme were acylated with resultant inhibition or activation of the dehydrogenase activity of the enzyme depending on the relative concentrations of the substrates and reactants, and on the mixing conditions. The enzyme catalysed the hydrolysis of p-nitrophenylacetate in the presence of NADH but with no significant production of acetaldehyde. It was conclude d that ester hydrolysis does not occur at the site of aldehyde oxidation. Preliminary studies on the reaction of the diethylpyrocarbonate indicated that the enzyme may catalytically essential histidine residue.
    Date
    1986
    Author
    Motion, Rosemary Lynne
    Rights
    The Author
    Publisher
    Massey University
    Description
    Irregular pagination: missing page 61. Content removed due to copyright restrictions: MacGibbon, A. K., Motion, R. L., Crow, K. E., Buckley, P. D., & Blackwell, L. F. (1979). Purification and properties of sheep-liver aldehyde dehydrogenases. European Journal Of Biochemistry, 96(3), 585-595. Motion, R. L., Blackwell, L. F., & Buckley, P. D. (1984). Activating effect of p-(chloromercuri)benzoate on the cytoplasmic aldehyde dehydrogenase from sheep liver. Biochemistry, 23(26), 6851-6857.
    URI
    http://hdl.handle.net/10179/4202
    Collections
    • Theses and Dissertations
    Metadata
    Show full item record

    Copyright © Massey University
    | Contact Us | Feedback | Copyright Take Down Request | Massey University Privacy Statement
    DSpace software copyright © Duraspace
    v5.7-2020.1-beta1
     

     

    Tweets by @Massey_Research
    Information PagesContent PolicyDepositing content to MROCopyright and Access InformationDeposit LicenseDeposit License SummaryTheses FAQFile FormatsDoctoral Thesis Deposit

    Browse

    All of MROCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    Copyright © Massey University
    | Contact Us | Feedback | Copyright Take Down Request | Massey University Privacy Statement
    DSpace software copyright © Duraspace
    v5.7-2020.1-beta1