The delivery of reporter genes into cells has become the primary means by which researchers study gene function and gene expression regulation. LacZ is a commonly used reporter gene in transfection experiments because the gene product, β-galactosidase, is very stable and resistant to proteolytic degradation and easily assayed. Cell Biolabs' β-galactosidase Staining Kit provides an easy-to-use and efficient method to determine the transfection efficiency and expression of LacZ gene. β-galactosidase catalyzes the hydrolysis of X-gal, which produces a blue color in cells expressing the transfected gene. Each kit provides sufficient quantities to perform up to 75 assays in 35 mm dishes.