Light regulation of chloroplast enzymes

: The activity of various chloroplast enzymes is regulated by a covalent redox-modification cycle driven by photosynthetic electron flow and oxygen, and is fine-tuned by effectors specific for each target enzyme. The regulatory principle resembles the protein phosphorylation/dephosphorylation system. The primary structures of some redox-modulated enzymes reveal characteristic extra cysteine-carrying peptides in addition to very conserved sequences.