Researchers at the University of Calgary have discovered the
unique genes that allow the opium poppy to make codeine and
morphine, thus opening doors to alternate methods of producing
these effective painkillers either by manufacturing them in a lab
or controlling the production of these compounds in the plant.
"The enzymes encoded by these two genes have eluded plant
biochemists for a half-century," says Peter Facchini, professor in
the Department of Biological Sciences, who has dedicated his career
to studying the unique properties of the opium poppy. "In finding
not only the enzymes but also the genes, we've made a major step
forward. It's equivalent in finding a gene involved in cancer or
other genetic disorders."
The researchers' findings will be published in a paper entitled
Dioxygenases catalyze the O-demethylation steps of morphine
biosynthesis in opium poppy, appearing in the on-line edition of
Nature Chemical Biology (http://www.nature.com/nchembio/index.html)
on Sun., Mar. 14 at 2 pm ET / 6 pm London time.
Codeine is by far the most widely used opiate in the world and
one of the most commonly used painkillers. Codeine can be extracted
directly from the plant, most codeine is synthesized from the much
more abundant morphine found in opium poppy. Codeine is converted
by an enzyme in the liver to morphine, which is the active
analgesic and a naturally occurring compound in humans. Canadians
spend more than $100 million every year on codeine-containing
pharmaceutical products and are among the world's top consumers of
the drug per capita. Despite this, Canada imports all of its
opiates from other countries.
"With this discovery, we can potentially create plants that will
stop production at codeine. We are also working toward the
synthesis of codeine and other opiate drugs more efficiently and
economically in controlled
bioprocessing facilities," says Facchini. "Our discovery now makes
it possible to use microorganisms to produce opiate drugs and other
important pharmaceuticals." One of the next steps for the research
team is using the codeine gene to produce pharmaceuticals in yeast
or bacteria.
Jillian Hagel, a post-doctoral scientist in Facchini's lab, was
assigned the task of finding these key genes as part of her Ph.D.
research. She succeeded using leading-edge genomics techniques that
helped her sort through up to 23,000 different genes and ultimately
find a gene called codeine O-dementhylase (CODM) that produces the
plant enzyme converting codeine into morphine.
"That was an exciting day," Hagel says of her moment of
discovery. "We have found the missing pieces that were needed to
understand how the opium poppy makes morphine."
Facchini adds: "The evolution of these two genes in a single
plant species has had such a huge impact on humanity over the past
several thousand years. Our discovery allows this unique genetic
power to be harnessed in many important ways."
SOURCE
