Enkephalins Prouduced in Transgenic Plants Using Modified 2S Seed Storage Proteins

We have explored the possibility of producing large amounts of biologically active peptides as part of chimeric plant seed storage proteins, the 2S albumins. A portion of an Arabidopsis thaliana 2S albumin gene, encoding a region of the protein whose sequence is not highly conserved among different species, was replaced by sequences encoding the neuropeptide Leu-enkephalin, flanked by tryptic cleavage sites. Using Agrobacterium mediated transformation, the modified gene was transformed into Arabidopsis and oilseed rape and the 2S albumins isolated from the seeds of the regenerated transgenic plants. These were digested with trypsin and the enkephalin containing peptide isolated and treated to remove the extra lysine residue. Up to 200 nmol of peptide were recovered per gram of seed.