ABSTRACT
The even chain length and regular spacing of these clusters allows amylopectin to form a semi-crystalline structure, with regular layers within the starch granule. The even chain length and regular spacing of these clusters allows amylopectin to form a semi-crystalline structure, with regular layers within the starch granule. Net carbon fixation allows phosphorylated intermediates to be withdrawn from the Calvin-Benson cycle for synthesis of various products, of which sucrose and starch are usually the most abundant. Sucrose is synthesized in the cytosol using triose-phosphates exported from the chloroplast via the triose-phosphate translocator, while starch is made in the chloroplasts. Starch can be degraded hydrolytically by endo- and exo-amylases to produce malto-oligosaccharides of various sizes, or phosphorolytically by starch phosphorylase. Several additional enzymes are required for the complete degradation of glucan chains.
