How much medicine can a GM plant make?
Not a lot. That’s why researchers this week outlined plans to grow entire fields of plants that have been genetically modified to produce pharmaceuticals. The process, known as pharming, exploits plants’ ability to manufacture complex molecules. Insert the right genes, and the plant will produce proteins and antibodies that can be turned into medicines. According to Julian Ma, the St George’s Hospital researcher coordinating the project, the technique could provide a cheap way of treating HIV, rabies, diabetes and TB. To make an impact, you need a lot of plants though. If you extracted all of the soluble protein from a GM plant, only 1-2% of it would be the drug compound you are after. Studies by the biotech giant Monsanto have shown that a kilogram of GM maize seed contained just 0.5-1.5g of the antibody it was trying to manufacture. But this is in raw form. More is lost during extraction and purification. Monsanto, which was aiming to produce 500kg of antibodies each year, calculated
