Akt is a protein kinase that can be activated by insulin and various growth factors and functions in a pathway involving PI3 kinase. Recent evidence suggests that Akt functions to promote cell survival by actively inhibiting apoptosis. The Akt Activity Assay Kit utilizes an Akt-specific antibody to immunoprecipitate Akt from cell lysate. Activity of the Akt is then determined in a kinase reaction using recombinant GSK-3 as substrate. Phosphorylation of the GSK-3 can be analyzed by Western blot analysis using the phospho-GSK-3 specific antibody included in the kit. The kit specifically detects Akt activity; other kinase activities are not detected.