# Nonlinear Chemical Dynamics: The Peroxidase-Oxidase Reaction

Nonlinear Chemical Dynamics: The Peroxidase-Oxidase Reaction

The peroxidase-oxidase (or PO) reaction is an enzyme-catalyzed chemical reaction that has been extensively studied in horseradish plants. The overall reaction can be modeled by a set of four first-order ODEs developed by Lars Olsen [2], which represent the reactants, products, and intermediates of the reaction. What makes this reaction so special is its nonlinear nature; with the right parameters, oscillatory behavior, period doubling, and chaos can be observed.

2NADH++22+2O

O

2

+

H

+

NAD

H

2

The equations in this Demonstration were taken directly from [1] and are as follows:

A'=(-A)-ABYB'=-BX-ABYX'=BX-2+3ABY-X+Y'=2-Y-ABY

k

7

A

0

k

3

k

8

k

1

k

3

k

1

k

2

2

X

k

3

k

4

k

6

k

2

2

X

k

5

k

3

Here to represent rate constants of the intermediate reactions; , , , and represent , , , and , respectively, with their differentials representing their intermediates.

k

1

k

8

A

B

X

Y

O

2

NADH

NAD+

CoIII

The suggested settings are =0.35, =250, =0.035, =20, =5.35, =, =0.1, =0.825, =8, , , , .

k

1

k

2

k

3

k

4

k

5

k

6

-6

10

k

7

k

8

a

0

A(0)=6

B(0)=58

X(0)=0

Y(0)=0