Involved in synthesis of starch. Catalyzes the synthesis of ADP-glucose, a molecule that serves as an activated glycosyl donor for alpha-1,4-glucan synthesis. Essential for starch synthesis in leaf chloroplasts and endosperm amyloplasts. alpha-D-glucose 1-phosphate + ATP + H(+) = ADP-alpha-D-glucose + diphosphate Activated by 3'phosphoglycerate, inhibited by orthophosphate. Allosteric regulation. Glycan biosynthesis; starch biosynthesis. Heterotetramer composed of two small and two large subunits. Expressed in leaves. Expressed in developing seeds from 10 to 20 days after flowering (DAF). Induced by sucrose, glucose and abscisic acid (ABA). Belongs to the bacterial/plant glucose-1-phosphate adenylyltransferase family.