Analytical utilization of phenylfluorone as a hydrogen donor substrate for peroxidase

Phenylfluorone (PF) is used as an efficient hydrogen donor substrate for peroxidase. Based on the horseradish peroxidase (HRP)-hydrogen peroxide-PF catalytic system, the spectrophotometric methods for the measurement of HRP activity and the determination of hydrogen peroxide are proposed. The quantitative assay of HRP is sensitive to 9.2 x 10(-12) mol/liter, and the calibration curve for hydrogen peroxide by a equilibrium procedure is linear in the range from 1.2 x 10(-7) to 1.6 x 10(-5) mol/liter. The system can be easily coupled with a glucose oxidase-catalyzed reaction, and glucose in human serum has been determined with the same results by a phenol-4-aminoantipyine method. Phenylfluorone offers advantages over some presently used chromogenic substrates in the sense of sensitivity and simplicity of the substrate system. (C) 1999 Academic Press.