title: A novel ISFET-type biosensor based on P450 monooxygenases.
abstract: We made a biosensor based on ion-sensitive field effect transistor (ISFET) using P450 monooxygenase. ISFETs are electrical devices and have been used as pH sensors. We used genetically engineered P450 monooxygenase for our research because of its high enzymatic activity. The fusion enzyme between rat CYP1A1P450 monooxygenase and yeast NADPH-cytochrome P450 oxidoreductase was expressed in yeast Saccharomyces cerevisiae strain AH22. Yeast microsomal membranes were immobilized in an agarose layer on the ISFET. o-Deethylation of 7-ethoxycoumarin to 7-hydroxycoumarin was catalyzed by the enzyme in the presence of nicotinamide adenine dinucleotide phosphate reduced form (NADPH). Formation of 7-hydroxycoumarin from 7-ethoxycoumarin was also measured by fluorescence. The difference of the voltage between the ISFET device and control device without enzymes showed a voltage increase along with the enzymatic reaction of P450 monooxygenases, and this voltage increase in the device was inhibited by addition of MnCl(2), an inhibitor of P450 monooxygenase. There was a positive correlation between the voltage increase in the ISFET device and the fluorescence intensity. This is the first electrochemical biosensing using P450 monooxygenases immobilized on the ISFET, and is applicable to the sensing of chlorophenol compounds.
authors.affiliation: National Institute of Bioscience and Human-technology (NIBH), Agency of Industrial Science and Technology (AIST), Ministry of International Trade and Industry (MITI), Tsukuba, Japan. masayuki-hara@aist.go.jp
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hara
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Yasuda
authors.forename: Hideki
authors.initials: H
authors.lastname: Toyotama
authors.forename: Hideo
authors.initials: H
authors.lastname: Ohkawa
authors.forename: Tsunenori
authors.initials: T
authors.lastname: Nozawa
authors.forename: Jun
authors.initials: J
authors.lastname: Miyake
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002733:Chlorophenols / Q000032:analysis; D019363:Cytochrome P-450 CYP1A1 / Q000037:antagonists & inhibitors*; D004563:Electrochemistry; D006863:Hydrogen-Ion Concentration; D008345:Manganese / Q000494:pharmacology
chemical_list: D002733:Chlorophenols; D008345:Manganese; D019363:Cytochrome P-450 CYP1A1; C116190:3,5-dichlorophenol