Successful development of affordable molecular therapies will require fundamentally new approaches to simultaneous production and bioprocessing of recombinant proteins. For example, metabolic storage disorders are the most common group of hereditary abnormalities and many of these conditions are likely to be treatable by supplementation with exogenously produced enzymes. Yet for any particular molecular defect, small numbers of individuals are affected and therefore projected treatment costs are very high. Fabry disease is a recessive X-linked deficiency in the catabolic activity of the lysosomal hydrolase alpha-galactosidase A (Ga1-A) and is the second most common hereditary metabolic storage disorder of man. The overall objective of this proposal is to determine the feasibility of economically producing custom-designed recombinant Ga1-A for therapeutic treatment of Fabry disease. Ga1-A from human sources has a homodimeric glycoprotein structure with a subunit molecular weight of approximately 50 kDa. In initial experiments, we cloned the Gal-A gene into a viral vector and established technical feasibility for the production and purification of this enzyme from transfected plant leaves. The yield, purity and quality of the enzyme warrant further biochemical and structural analyses to evaluate its suitability for transfusions into human subjects.
This technology will establish plants as an important and economical source of the large quantities of recombinant proteins necessary to advance modern molecular therapies. Cost advantages are based on the rapidity of the viral transfection, the favorable levels of product enrichment in crude extracts, and the high yield of product obtained from plant biomass, a renewable and low-input and easily scalable source.
