Glucose and cAMP work in opposition with one another through covalent modifier regulation. While cAMP binds to Ser196 and Thr666 binding sites of ChREBP, causing the phosphorylation and inactivation of pyruvate kinase; glucose binds to Ser196 and Thr666 binding sites of ChREBP, causing the dephosphorylation and activation of pyruvate kinase. As a result, cAMP and excess carbohydrates are shown to play an indirect role in pyruvate kinase regulation.[16]