The human enzymes produced in tobacco could someday provide low-cost treatment for Gaucher's disease and other genetic disorders
Blacksburg, Va., -- The U.S. Patent and Trademark Office yesterday issued patent 5,929,304 for "Production of Lysosomal Enzymes in Plant-based Expression Systems" to Carole Cramer, Virginia Tech professor of plant pathology, physiology, and weed sciences, Karen Oishi, vice president of research at CropTech,, David Radin, president of CropTech, and Deborah Weissenborn, director of regeneration and propagation at CropTech.
The researchers are using tobacco plants to produce human lysosomal enzymes. These enzymes are deficient in individuals with rare lysosomal storage diseases, such as Gaucher's disease. Replacement therapy with recombinant enzymes holds tremendous promise for correcting the severe abnormalities associated with these diseases, says Cramer.
One enzyme, glucocerebrosidase (hGC), is currently produced using a mammalian cell culture system. Patients usually receive the treatment every two weeks for life. Treatment costs currently average $160,000 a year, making this one of the most expensive drugs in the world, in large part due to manufacturing costs. CropTech researchers have put the gene for glucocerebrosidase into tobacco and shown that an enzymatically active enzyme is produced in tobacco leaves. In the plants making glucocerebrosidase at the highest levels, leaves from a single tobacco plant could make enough enzyme for one dose.
Many human proteins, like glucocerebrosidase, also contain sugars called glycans as well as amino acids. Tobacco puts glycans on the right spot on the human protein but the exact composition of the sugars may be different, making the enzyme potentially inappropriate for use in humans. Researchers at the Fralin Biotechnology Center at Virginia Tech are assessing the sugar composition of human glycoproteins made in plants and developing novel strategies to engineer tobacco to synthesized "human-compatible" glycans.
For more about Cramer and her research, see
www.biotech.vt.edu/Teaching/Faculty/Cramer.html
Also see a related news release at:
/www.vt.edu:10021/ur/news/Archives/May98/98223.html
For more information about this and other patents, contact Mike Martin at Virginia Tech Intellectual Properties, Inc., 540- 951-9376, email martinmj@vt.edu.
For more information about CropTech Corporation, contact Dr. Brandon Price, CEO at CropTech, 540-951-2888 X3003, email: bprice@croptech.com.