||Green Fluorescent Protein (GFP) is a spontaneously fluorescent protein originally isolated from the jellyfish Aequorea Victoria (Chalfie et al, 1994). GFP has been recombinant modified and enhanced (called EGFP). GFP and EGFP have been widely used as a valuable reporter molecule for in vivo visualization of gene expression events in a variety of cell types and organisms. Since GFP requires no additional substrates or cofactors, GFP fluorescence can be easily detected under fluorescence microscope. However, most imaging studies of GFP are only qualitative. Since quantitative analysis of GFP expression level in cells or tissues are more informative and have wide applications. We has developed the GFP Quantification Kit which quantifies GFP in 96 micro-plate format. Cells or tissues can be homogenized directly in the GFP Assay Buffer. The quantity of GFP is determined by comparing its fluorescence with that of GFP standard. The kit can detect a wide range of GFP concentration (0.01-10 µg/ml). A GFP quench solution is also provided for determining auto-fluorescence of cell or tissue extracts. Each kit provides sufficient reagents to perform up to 100 assays, Ex/Em = 488nm/507nm.