The recombinant CFP (Cyan Fluorescent Protein) is expressed and purified from transformed E. coli using a method that ensures high purity and maximal CFP fluorescence. Endotoxin has been removed, so the protein is suitable for in vivo injection or cell culture applications. The protein is a 31.3 kDa monomer with 284 amino acids and an N-terminal His-tag, Ex./Em. = 458/480 nm, extinction coefficient 26000M^-1CM^-1.Fluorescent protein ideal for subcellular labeling/visualization.