Experimental and theoretical studies of the peroxidase-NADH biochemical oscillator: An enzyme-mediated chemical switch.

摘要

The peroxidase-NADH system is one of the few biochemical examples among known in vitro chemical oscillators. This system functions as a model for the development of methods and principles to study the nonlinear dynamics of cyclic, biochemical reactions. Experiments are conducted on a standard oscillator, which consists of a well-mixed, aqueous solution of the enzyme horseradish peroxidase and the common electron transfer dye, methylene blue (MB;A multidimensional approach to data acquisition is used to provide an improved experimental basis for more realistic modeling. Oscillatory dynamics were investigated, including oxygen mass transport, the role of MB;To simulate experimental results, a minimal model is developed which incorporates chemically realistic parameters. The model consists of thirteen reactions and rate constants, and fifteen species. Nine of the rate constants are from the published literature, and four originate from experimental measurements described here. In the model, two reactions of superoxide perform a key function as an enzyme-mediated chemical switch. In oscillatory simulations, the oxidation of Per;The success of the straightforward approach used to build the model demonstrates that chemical knowledge can be applied to create an oscillatory system without invoking abstract models as a starting point. The postulated kinetic scheme presented here has its greatest potential as a chemically realistic bridge between experiment and theory.