Complex dynamics have been become increasingly important in biochemical and physiological contexts in recent years. A good example for studying the nonlinear and non-equilibrium dynamics is the peroxidase-oxidase (PO) reaction. The PO reaction involves the oxidation of reduced nicotinamide adenine dinucleotide (NADH) by molecular oxygen and overall reaction catalyzed by horseradish peroxidase (HRP). The non-linear behavior of this reaction is usually realized in a reactor containing the HRP, methylene blue (MB), and 2,4- dichlorophenol (DCP). NADH and O_2 are supplied continuously to this reaction mixture from external sources. In this paper, the experimental system and methods of the Peroxidase-Oxidase biochemical oscillator has been set up successfully. Different kinds of oscillating waves such as simple periodic, quad-periodic, chaos and damped oscillation have been found based on this experimental system and methods. To protect the cells and organ systems of the body against reactive oxygen species, humans have evolved a highly sophisticated and complex antioxidant protection system. It involves a verify of components such as glutathione (GSH) to neutralize free radicals. The antioxidation effect of glutathione is determined by the "probe" of this biochemical oscillator. Experiment indicates that it can be as a base of quantitative analysis. The method relies on the linear relationship between the changes in the amplitude of the biochemical oscillating and the concentration of GSH in the range 9.38 * 10~(-7) ～ 7.50 * 10~(-5) mol·L~(-1). Some possible mechanism of this reaction is discussed.

Key words: ENZYME, OSCILLATOR, GLUTATHIONE, REACTION MECHANISM