The recombinant YFP (Yellow Fluorescent Protein) is expressed and purified from transformed E. coli using a method that ensures high purity and maximal YFP fluorescence. Endotoxin has been removed, so the protein is suitable for in vivo injection or cell culture applications. The protein is a 26.4 kDa monomer with 238 amino acids, Ex./Em. = 525/538 nm, extinction coefficient 27390. MW: 26.4 kDa. Purity ≥97%