Purity ≥97% (reverse phase HPLC). Because of an alanine for serine substitution, this peptide is not a substrate for glycogen synthase kinase 3, but instead serves as a negative control. The peptide is similar to skeletal muscle glycogen synthase; it contains sites 3b and 3c. Site 4, however, is replaced with alanine. This peptide is a negative control for assay of G8170-46 activity. G8170-26, but not this lot of GS-2 (Ala21) peptides Sequence: YRRAAVPPSPSLSRHSSPHQAEDEEE. Applications: Suitable for use in Protein Phosphorylation Assays. Other applications have not been tested.