Zyagen tissue lysate (total protein) is extracted from freshly harvested tissues in protein lysis buffer supplemented with a cocktail of 7 mammalian protease inhibitors to minimize proteolysis. The extracted protein is precisely quantified and packed in 1.5-ml tubes at a concentration of 5mg/ml. Protein is stable for one year if stored properly at -80oC. The quality of protein is verified by denatured SDS-PAGE with Coomassie blue staining. The integrity of protein is tested by immunoblotting using specific beta-actin antibody. The extracted protein is ready for immediate use in reporter assays (e.g., luciferase, beta-galactosidase, chloramphenicol acetyl transferase), protein kinase assays (e.g., PKA, PKC, tyrosine kinase), immunoassays (e.g., Western blots, ELISAs, RIAs) and/or protein purification procedures, immunoprecipitation, SDS-PAGE, isoelectric focusing gels and SDS-capillary electrophoresis, enzymatic activity analysis, gel shifting assay, and protein-protein interaction.