Abstrakt
Regulation of enzyme activities during stress conditions in plants is crucial for their survival. Due to their immobility plants cannot escape from unfavorable extrinsic environment.
Contrarily plants have to withstand stress by extensive intrinsic rearrangements of primary and secondary metabolism. In enzyme regulation pH, concentration of substrates, coenzymes, and cofactors and the presence of activators and inhibitors play a pivotal role.
Inhibition by excess of substrate is a possible regulation, too. Enzyme activity especially during stress could be regulated by synthesis de novo.
Furthermore, some chaperons can increase enzyme activity. Also enzyme oligomerization state and above all posttranslational modifications (PTMs) are the key modulators of enzyme activity.
The multiple levels of enzyme regulation are discussed using concrete examples.