Bhat, Santhoor G and Vaidyanathan, S Chelakara (1976) Purification and Properties of l-4-Hydroxymandelate Oxidase from Pseudomonas convexa. In: European Journal of Biochemistry, 68 (2). pp. 323-331.
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An inducible membrane-bound l-4-hydroxymandelate oxidase (decarboxylating) from Pseudomonas convexa has been solubilized and partially purified. It catalyzes the conversion of l-4-hydroxymandelic acid to 4-hydroxybenzaldehyde in a single step with the stoichiometric consumption of O2 and liberation of CO2. The enzyme is optimally active at pH 6.6 and at 55 oC. It requires FAD and Mn2+ for its activity. The membrane-bound enzyme is more stable than the solubilized and purified enzyme. After solubilization it gradually loses its activity when kept at 5 oC which can be fully reactivated by freezing and thawing. The Km values for DL-4-hydroxymandelate and FAD are 0.44 mM and 0.038 mM respectively. The enzyme is highly specific for DL-4-hydroxymandelic acid. DL-3,4-Dihydroxymandelic acid competitively inhibited the enzyme reaction. From the Dixon plot the Ki for DL-3,4-dihydroxymandelic acid was calculated to be 1.8 × 10−4 M. The enzyme is completely inactivated by thiol compounds and not affected by thiol inhibitors. The enzyme is also inhibited by denaturing agents, heavy metal ions and by chelating agents.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to John Wiley & Sons, Inc. 1999-2009.|
|Department/Centre:||Division of Biological Sciences > Biochemistry|
|Date Deposited:||10 Dec 2009 12:40|
|Last Modified:||19 Sep 2010 05:48|
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