||The recombinant EGFP is expressed and purified from transformed E. coli using a method that ensures high purity and maximal GFP fluorescence. Endotoxin has been removed, so the protein is suitable for in vivo injection or cell culture applications. The recombinant EGFP (Gene Bank Accession no. U57607) is a 32.7 kDa monomer with 293 amino acids tagged with 6XHis on both N- and C-terminus. Therefore, the EGFP can be detected by both His-tag antibody and GFP antibody on Western Blot analysis. The excitation and emmission spectra for the recombinant EGFP is identical to GFP purified from Aequorea Victoria (Chalfie et al, 1994), with Ex/Em = 488/507 nm (ε489 nm = 55,000 M?? Cm??; ε280 nm = 21980 M?? Cm??).