Photosynthesis ferredoxin/thioredoxin system

Both potato tuber and potato leaf ADP-Glc PPases are plas-tidic the leaf enzyme is in the chloroplast, and the tuber enzyme is in the amyloplast (74). The ferredoxin-thioredoxin system is located in the chloroplast and thus, with photosynthesis, reduced thioredoxin is formed and activated within the leaf ADP-Glc PPase. At night, oxidized thioredoxin is formed it oxidizes and inactivates the ADP-Glc PPase. This activation/inactivation process during the light/dark cycle allows a fine tuning and dynamic regulation of starch synthesis in the chloroplasts. Thioredoxin isoforms are present in many different subcellular locations of plant tissues cytosol, mitochondria, chloroplasts, and even nuclei (75) and are also present in amyloplasts (76). 

Evolution of Oxygen by an Aquatic Plant Light is the principal regulator of photosynthesis. Light affects the activities of regulatory enzymes in photosynthetic processes by indirect mechanisms, which include changes in pH, Mg2+ concentration, the ferredoxin-thioredoxin system, and phytochrome. 

Buchanan, B. B. 1991. Regulation of CO2 assimilation in oxygenic photosynthesis the ferredoxin/thioredoxin system. Perspective on its discovery, present status, and future development. Arch. Biochem. Biophys. 288 1 9. 

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