title: Kinetics of barley FA hydroperoxide lyase are modulated by salts and detergents.
abstract: The cDNA from barley coding FA hydroperoxide lyase (HPL) was cloned. A recombinant protein derived from the cDNA was expressed in Escherichia coli as an active enzyme. Thus far, there have been no reports on HPL in monocotyledonous plants. The recombinant protein was shown to be most active to linolenic acid 13-hydroperoxide, followed by linoleic acid 13-hydroperoxide. 9-Hydroperoxides of the FA could not be substrates for the recombinant HPL. The activity was dramatically enhanced in the presence of a detergent and/or a salt in the reaction mixture. At the same time, the kinetics of the reaction, including inactivation and the Vmax value of the HPL, were also greatly modulated, depending on the concentration of a monovalent cation and/or a detergent in the reaction mixture. These results suggest that these effectors induced a conformational change in barley HPL, resulting in an improvement in substrate binding and in enzyme activity.
authors.affiliation: Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yoshida 1677-1, Yamaguchi, 753-8515, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Koeduka
authors.forename: Michael
authors.initials: M
authors.lastname: Stumpe
authors.forename: Kenji
authors.initials: K
authors.lastname: Matsui
authors.forename: Tadahiko
authors.initials: T
authors.lastname: Kajiwara
authors.forename: Ivo
authors.initials: I
authors.lastname: Feussner
mesh_terms: D000446:Aldehyde-Lyases / Q000235:genetics / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D003902:Detergents / Q000378:metabolism*; D001467:Hordeum / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012492:Salts / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D003902:Detergents; D012492:Salts; D003577:Cytochrome P-450 Enzyme System; D000446:Aldehyde-Lyases; C054540:hydroperoxide lyase