[New look at starch degradation in Arabidopsis thaliana L. chloroplasts].

Transitory starch is accumulated during the day and is the main source of energy for the cell metabolism during the night. The observed periodical starch degradation has become a model often used by scientist in their experiments. Starch granule degradation could be divided into 2 periods: initiation of degradation and digestion of amylopectin and amylose into maltooligosaccharide and their derivative. Key meaning is attributed in this process to beta-amylaze, product of its activity beta-maltose is transported to the cytosole and there it subjects farthest conversions. It has been demonstrated that a number of enzymes take part in the starch degradation process. However, the way of regulating their activity is still not fully explained. There is most important elements effecting rate of starch decomposition: day cycle, starch phosphorylation and regulation of enzyme activity. It proceeds through redox potential, pH changes and phosphorylation of protein involved in starch degradation due specific phosphatases. The purpose of the current work is to systematize the knowledge of the Arabidopsis thaliana L. leaf starch degradation. The results of the recent research cast a new light on the starch degradation process as well as on its control.