title: [Flavonoids: efficient protectors of glucose-6-phosphate dehydrogenase from ultrasonic cavitation-induced inactivation].
abstract: Seven structurally diverse flavonoids have been shown to decrease glucose-6-phosphate dehydrogenase (G6PDH) inactivation in 0.1 M phosphate buffer (pH 7.4), induced by exposure to a high temperature (44 degrees C), or by a low-frequency ultrasound (27 kHz, 60 Wt/cm2). The activity of the compounds was assessed by their ability to change effective first-order rate constants characterizing the total (thermal and ultrasonic), thermal, and ultrasonic inactivation of 2.5 nM G6PDH (k(in), k(in)* [Russian characters: see text] kin(us), respectively). The value dependences of these constants on flavonoid concentrations (0.01-50 microM) were obtained. Rank order of potency exhibited by the compounds in protecting G6PDH appeared as follows: hesperidin > morin > silibin > naringin = quercetin > kampferol >> astragalin. The data obtained confirm the crucial role of free radicals formed in the field of ultrasonic cavitation (HO* and O2*-) in G6PDH inactivation in solutions.
authors.forename: E I
authors.initials: EI
authors.lastname: Karaseva
authors.forename: V P
authors.initials: VP
authors.lastname: Kurchenko
authors.forename: D I
authors.initials: DI
authors.lastname: Metelitsa
mesh_terms: D004795:Enzyme Stability; D005419:Flavonoids / Q000737:chemistry*; D005954:Glucosephosphate Dehydrogenase / Q000737:chemistry*; D006358:Hot Temperature; D017665:Hydroxyl Radical / Q000737:chemistry*; D007700:Kinetics; D013010:Sonication; D013481:Superoxides / Q000737:chemistry*
chemical_list: D005419:Flavonoids; D013481:Superoxides; D017665:Hydroxyl Radical; D005954:Glucosephosphate Dehydrogenase