Regulation of Starch Biosynthesis in Plant Leaves: Activation and Inhibition of ADPglucose Pyrophosphorylase

摘要: The ADPglucose pyrophosphorylases of 7 plant-leaf tissues were partially purified and characterized. In all cases the enzymes showed stability to heat treatment at 65° for 5 minutes in presence 0.02 m phosphate buffer, pH 7.0. leaf activated 15-fold by 3-phosphoglycerate. Fructose-6-phosphate fructose 1, 6-diphosphate stimulated pyrophosphorylase lesser extents. A 0.5 (conc activator required give 50% observed maximal activation) 3-phosphoglycerate barley enzyme was × 10 −6 while sorghum it 3.7 −4 m. Inorganic proved be an effective inhibitor synthesis. I that gave inhibition activity various varied from 2 −5 (barley) 1.9 (sorghum). This reversed or antagonized These results form basis hypothesis regulation starch biosynthesis.