The calcineurin substrate peptide corresponds to a sequence from the regulatory RII subunit of cAMP-dependent protein kinase. Calcineurin substrate can be used for assaying protein phosphatase-2B (calcineurin) activity.H-Asp-Leu-Asp-Val-Pro-Ile-Pro-Gly-Arg-Phe-Asp-Arg-Arg-Val-Ser-Val-Ala-Ala-Glu-OH or H-DLDVPIPGRFDRRVSVAAE-OH