Involved in the biosynthesis of ADP-glucose, a building block required for the elongation reactions to produce glycogen. Catalyzes the reaction between ATP and alpha-D-glucose 1-phosphate (G1P) to produce pyrophosphate and ADP-Glc. alpha-D-glucose 1-phosphate + ATP + H(+) = ADP-alpha-D-glucose + diphosphate Allosterically activated by fructose-1,6-bisphosphate (F16BP), hexanediol 1,6-bisphosphate, NADPH and pyridoxal phosphate. Inhibited by AMP and by high concentrations of MgCl(2). kcat is 111 sec(-1) for adenylyltransferase activity. kcat is 81 sec(-1) for pyrophosphorylase activity. Glycan biosynthesis; glycogen biosynthesis. Homotetramer; dimer of dimers. mRNA stability is at least partially under the control of CsrA; loss of csrA leads to higher transcript levels, possibly mediated by protein binding to the mRNA (PubMed:7751274). Displays cooperative behavior and a bibi mechanism with sequential binding of ATP and G1P, followed by ordered release of pyrophosphate and ADP-Glc. Belongs to the bacterial/plant glucose-1-phosphate adenylyltransferase family.