Bistability and reaction thresholds in the phenol-inhibited peroxidase-catalyzed oxidation of indole-3-acetic acid.
A model mechanism for the phenol-inhibited peroxidase-catalyzed oxidation of indole-3-acetic acid (IAA) is proposed and analyzed. The model involves an autocatalytic free radical species that sustains IAA oxidation and the phenolic inhibitor acting as a free radical scavenger. Under a fixed set of parameter values, the model exhibits a coexistence of two stable steady states. This bistability phenomenon explains the origin of the experimentally observed threshold inhibitor concentrations above which IAA oxidation stops. The variation of the inhibitor threshold level with enzyme and substrate concentrations are reproduced by the model almost quantitatively.
Krylov
S N
SN
Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada P3E 2C6.
Aguda
B D
BD
Ljubimova
M L
ML