Dandelion PPO-1/PPO-2 domain-swaps: The C-terminal domain modulates the pH optimum and the linker affects SDS-mediated activation and stability

We propose that the linker and C-terminal domain fine-tune the activation of plant PPOs. The C-terminal domain adjusts the pH optimum and the linker probably contains an SDS-binding/interaction site that influences inactivation and determines the SDS concentration required for activation. For the first time, we have determined the influence of the three PPO domains on enzyme activation and stability providing insight into the regulation and activation mechanisms of type-3 copper proteins in general.