This invention relates in part to synthesizing high value pharmaceutical proteins in transgenic plants by chloroplast expression for pharmaceutical protein production. We use poly(GVGVP), for example, as a fusion protein to enable hyper-expression of insulin and to accomplish rapid one step purification of fusion peptides utilizing the inverse temperature transition properties of this polymer. We also use insulin-CTB fusion protein in chloroplasts of nicotine free edible tobacco (LAMD 605) for oral delivery. This invention includes expression of native cholera toxin B subunit gene as oligomers in transgenic tobacco chloroplasts which may be utilized in connection with large-scale production of purified CTB, as well as an edible vaccine if expressed in an edible plant, as a transmucosal carrier of peptides to which it is fused to enhance mucosal immunity, and/or to induce oral tolerance of the products of these peptides. The present invention also relates in part to recombinant DNA vectors for enhanced expression of human serum albumin, insulin-like growth factor I, and interferon-α 2 and 5, via chloroplast genomes.
