(ORDO NEWS) — For the first time, biologists have identified the natural pathway for the synthesis of cocaine and transferred the corresponding genes to tobacco plants, “teaching” them to produce small amounts of the drug.
Cocaine is a dangerous drug that is extracted from coca leaves. At the same time, the set of chemical reactions by which the plant produces it was still completely unknown.
A team of Chinese scientists from the Kunming Institute of Botany managed to determine the last steps in the biosynthesis of cocaine, and they were helped by other “natural producers” of drugs, tobacco plants.
Even in the distant past , the inhabitants of South America discovered that plants of the genus Erythroxylum produce alkaloids that have a stimulating and narcotic effect.
The key of these substances, cocaine, was isolated by scientists in the middle of the 19th century.
For a long time, it was widely used as a medicine and stimulant, but due to addiction and other negative health effects, it was added to the list of prohibited substances and became illegal.
Today, cocaine is legally produced in very limited quantities and under the strictest control, solely for medical and scientific purposes.
There are methods that allow you to synthesize the substance from scratch and, of course, extract it from the leaves of the coca bush.
However, the pathway of cocaine formation in the plants themselves has not yet been fully determined.
It had previously been traced back to an intermediate, the hydroxybutanoic acid derivative MPOA, but the final steps involved in converting MPOA to cocaine remained unclear. It is only now that they have been identified.
At the final stages, MPOA molecules must pass through the reactions of methylation and oxidative cyclization.
Therefore, scientists led by Sheng-Xiong Huang (Sheng-Xiong Huang) examined the DNA of the coca bush to determine the sites that encode proteins that catalyze the corresponding reactions: methylases and oxidases.
They transferred the most promising genes into Bentham’s tobacco ( Nicotiana benthamiana ), a popular model organism for studying plant physiology.
Evaluating the performance of various pairs of enzymes, the authors concluded that the most effective combination was EnCYP81AN15 oxidase and EnMT4 methylase.
Under the action of the first protein, MPOA is cyclized, under the action of the second, it adds a methyl group, leading to the appearance of cocaine.
The leaves of such GM tobacco contained up to 400 nanograms of the drug per milligram of dried mass, which is less than five percent of that contained in the leaves of the coca bush.
Now that the complete biosynthetic pathway for cocaine has been established, the appropriate genes can be transferred into bacteria to produce the substance in the quantities needed for medicine and science.
At the same time, scientists emphasize that their work will not bring any benefit to the illegal drug business.
According to them, the production of cocaine in the traditional way, from coca leaves, is much easier and cheaper, and GM bacteria are unlikely to be attractive to drug cartels.
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