flavin-adenine-dinucleotide and 10-hydroxy-12-octadecenoic-acid

Linoleic acid Δ9 hydratase, which is involved in linoleic acid saturation metabolism of Lactobacillus plantarum AKU 1009a, was cloned, expressed as a his-tagged recombinant enzyme, purified with an affinity column, and characterized. The enzyme required FAD as a cofactor and its activity was enhanced by NADH. The maximal activities for the hydration of linoleic acid and for the dehydration of 10-hydroxy-cis-12-octadecenoic acid (HYA) were observed at 37 °C in buffer at pH 5.5 containing 0.5 M NaCl. Free C16 and C18 fatty acids with cis-9 double bonds and 10-hydroxy fatty acids served as substrates for the hydration and dehydration reactions, respectively. The apparent Km value for linoleic acid was estimated to be 92 μM, with a kcat of 2.6∙10(-2) s(-1) and a Hill factor of 3.3. The apparent Km value for HYA was estimated to be 98 μM, with a kcat of 1.2∙10(-3) s(-1).

Topics: Biocatalysis; Flavin-Adenine Dinucleotide; Hydrogen-Ion Concentration; Hydrolases; Kinetics; Lactobacillus plantarum; Linoleic Acid; Lipid Metabolism; NAD; Oleic Acids; Substrate Specificity; Temperature