During the process of the tissues and cells lysis, they released a large number of endogenous protein phosphatases, the latter catalyze the phosphorylated proteins to dephosphorylation in various ways. This product contains 3 independent protein phosphatase inhibitors, each can specifically inhibit the activities of one or several protein phosphatases. With the optimized contents, this product can restrain the activities of alkaline phosphatase, and serine / threonine phosphatase (PP1, PP2A) etc. It is 100× concentrated solution, can be directly added into any tissues and cells lysis product, can effectively inhibit the phosphorylated proteins to dephosphorylation, so as to maintain the phosphorylated state of proteins. It is apply to detect phosphorylated proteins, protein kinase activity, etc in Western Blot and Co-Immunoprecipitation.?