Methoxyresorufin as a substrate for the fluorometric assay of insect microsomal O-dealkylases

• Published in: Pesticide biochemistry and physiology Vol. 7; no. 4; pp. 349 - 354
• Main Authors: Mayer, Richard T., Jermyn, John W., Burke, M.Danny, Prough, Russell A.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.01.1977
• ISSN: 0048-3575; 1095-9939
• DOI: 10.1016/0048-3575(77)90038-4

Methoxy-, ethoxy-, propoxy-, and butoxyresorufin were prepared and tested as substrates for the fluorometric assay of O-dealkylation by the mixed-function oxidase system in house flies, Musca domestica L. Methoxyresorufin proved to be the most suitable substrate because of the favorable reaction rates. This sensitive assay can be performed with a minimum of microsomal protein (<0.3 mg/ml) in 5 min or less. The apparent K m and maximum velocity were calculated as 2.88 μ M and 0.27 nmol of resorufin produced/min/mg of microsomal protein, respectively. The O-dealkylation reaction required O 2 and NADPH and was inhibited by CO.