The glucoamylase inhibitor acarbose is a direct activator of phosphorylase kinase.
Nadeau OW, Liu W, Boulatnikov IG, Sage JM, Peters JL, Carlson GM. The glucoamylase inhibitor acarbose is a direct activator of phosphorylase kinase. Biochemistry. 2010 Aug 10; 49(31):6505-7.