Starch biosynthesis fractionation

This conclusion was confirmed by kinetic measurements. Preparations of purified cytosolic and plastidic phosphorylase isozymes from Pisum sativum were adjusted to an approximately equal activity concentration (as determined at saturating levels of soluble starch). Using these isozyme preparations kinetic measurements were performed at varying levels of the polysaccharide fraction. Orthophosphate or glucose 1-phosphate levels were saturating. The initial rates of phosphorolysis (Fig. 2A) or of polysaccharide biosynthesis (Fig. 2B) were determined. 

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