Albumin Can Be Grown in Rice

Scientists in China have successfully grown human serum albumin (HSA) in rice, which has been successfully used to grow other human proteins. Using a species of rice called Oryza sativa, the scientists used a bacterium to deliver the gene for making HSA into the rice plants, and after a few generations of breeding, the plants were making HSA reliably. The research team, based mainly in Wuhan, China, ran several tests to compare the rice and human versions of HSA, and both types had the same molecular mass, amino acid sequence and overall shape, among other similarities. Both versions were able to bind to the blood-thinning drug warfarin and to the painkiller naproxen. In rats with liver cirrhosis, the rice-derived HSA helped the animals eliminate excess abdominal fluid. The researchers also were able to extract the protein from rice in an efficient manner. Their twoday purification process captured about 46 percent of the protein in the plant, resulting in a yield of 2.75 grams of HSA from every kilogram of rice, enough to make commercial production feasible.

HSA is a protein that helps transport certain hormones, steroids and fatty acids in the bloodstream, and it is used to treat people with hemorrhagic shock, patients with serious burns and other medical conditions. It is also hoped that HSA can be put to use in other ways,such as delivering drugs or oxygen within the body. The worldwide demand for HSA exceeds 500 tons per year. The study was reported on October 31 in the Proceedings of the National Academy of Science.