The invention provides an expression cassette comprising a DNA sequence encoding amino acids 1-99 of human preproenkephalin, a DNA sequence encoding a precursor of a carboxy-amidated peptide flanked by dibasic cleavage sites and optionally a DNA sequence encoding a marker protein (such as Enhanced Green...http://www.google.fr/patents/US8003622?utm_source=gb-gplus-shareBrevet US8003622 - Peptide biosynthesis and pain therapy
