title: An unusual isotope effect on substrate inhibition in the oxidation of arachidonic acid by lipoxygenase.
abstract: Soybean lipoxygenase catalyzes the oxidation of arachidonic acid to 15S-HPETE. The reaction displays strong substrate inhibition with unlabeled substrate but no discernible substrate inhibition with arachidonic acid labeled with deuterium at C13, the site of hydrogen/deuterium atom abstraction. The unusual behavior is due primarily to a large kinetic isotope effect on Km,O2 as a result of the strong selection against deuterium in the abstraction step.
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA.
authors.forename: Sheng
authors.initials: S
authors.lastname: Peng
authors.forename: Wilfred A
authors.initials: WA
authors.lastname: van der Donk
mesh_terms: D016718:Arachidonic Acid / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D003903:Deuterium; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism; D007700:Kinetics; D019787:Linoleic Acid / Q000737:chemistry / Q000378:metabolism; D008084:Lipoxygenase / Q000737:chemistry / Q000378:metabolism*; D016859:Lipoxygenase Inhibitors / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D013025:Glycine max / Q000201:enzymology / Q000378:metabolism
chemical_list: D006893:Hydroxyeicosatetraenoic Acids; D016859:Lipoxygenase Inhibitors; D016718:Arachidonic Acid; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid; D019787:Linoleic Acid; D003903:Deuterium; C101084:lipoxygenase L-1; D008084:Lipoxygenase