Caltech engineers build mini drug-producing biofactorie...( PASADENA Calif.-- Researchers at the...)

PASADENA, Calif.-- Researchers at the California Institute of Technology have developed a novel way to churn out large quantities of drugs, including antiplaque toothpaste additives, antibiotics, nicotine, and even morphine, using mini biofactories--in yeast.

A paper describing the research, now available online, will be featured as the cover article of the September issue of Nature Chemical Biology.

Christina D. Smolke, an assistant professor of chemical engineering at Caltech, along with graduate student Kristy Hawkins, genetically modified common baker's yeast (Saccharomyces cerevisiae) so that it contained the genes for several plant enzymes. The enzymes allow the yeast to produce a chemical called reticuline, which is a precursor for many different classes of benzylisoquinoline alkaloid (BIA) molecules. The BIA molecules are a large group of chemically intricate compounds, such as morphine, nicotine, and codeine, which are naturally produced by plants.

BIA molecules exhibit a wide variety of pharmacological activities, including antispasmodic effects, pain relief, and hair growth acceleration. Other BIAs have shown anticancer, antioxidant, antimalarial, and anti-HIV potential.

"There are estimated to be thousands of members in the BIA family, and having a source for obtaining large quantities of specific BIA molecules is critical to gaining access to the diverse functional activities provided by these molecules," says Smolke, whose lab focuses on using biology as a technology for the synthesis of new chemicals, materials, and products. However, the natural plant sources of BIAs accumulate only a small number of the molecules, usually "end products" like morphine and codeine that, while valuable, can't be turned into other compounds, thus limiting the availability of useful new products.

To their reticuline-producing yeast, Smolke and Hawkins added the genes for other enzymes, from both plants and humans
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