Involved in the biosynthesis of ADP-glucose building block required in the biosynthesis of maltose-1-phosphate (M1P) and in the elongation reactions to produce linear alpha-1,4-glucans. 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 Glycan biosynthesis; glycogen biosynthesis. Capsule biogenesis; capsule polysaccharide biosynthesis. Inactivation of glgC reduces by half the extracellular (capsular) alpha-D-glucan and intracellular glycogen contents (PubMed:18808383, PubMed:27513637). Cells lacking this gene are not affected in their multiplication or persistence in the BALB/c mouse infection model (PubMed:18808383). Combined inactivation of both glgC and treS results in a complete absence of maltose-1-phosphate (M1P) and alpha-glucan, whereas combined inactivation of both glgC and otsA results only in a complete absence of alpha-glucan (PubMed:27513637). Maltose-1-phosphate (M1P) is generated by two alternative routes: the TreS-Pep2 branch and the GlgC-GlgM branch, however it seems that TreS-Pep2 branch provides most of M1P for the GlgE pathway in M.tuberculosis. Belongs to the bacterial/plant glucose-1-phosphate adenylyltransferase family.