Step aside, poppy. Biologists in California and Canada have created strains of yeast that can feast on sugar and make opiates – the key ingredients in pain relievers like morphine.
The new study, published today in the journal Nature Chemical Biology, represents a coup for scientists and drug companies that currently rely on extracting drugs like morphine and codeine directly from poppies and other plants, a process that’s expensive and can yield impurities that cause harmful side-effects. The discovery could mean cheaper medications — where biochemists brew large batches of pure opiates overnight rather than waiting months for poppy fields to grow. It could also have dangerous consequences if it falls into the wrong hands.
“This work is going to enable the production of novel [pain-relieving] analgesics that are safer and less addictive,” said MIT political scientist Kenneth Oye, who co-wrote an accompanying commentary for Nature Chemical Biology about possible regulations and was not involved with the research. “The other part of the equation is if those yeast strains work their way into broad circulation, then you’re talking about fundamental changes in illicit drug production and distribution.”
Yeast could streamline the drug-making process by bypassing plants, which grow slowly and produce only small amounts of chemicals, and moving the process instead to a beaker, where scientists could brew larger quantities of the drug.
To envision how researchers moved the opiate-making process from plants to yeast, picture a staircase with 15 steps. Glucose, a sugar compound, sits at the bottom, while the top level is filled with morphine, codeine and other members of a drug family known as benzylisoquinoline alkaloids (BIAs). At each step up, a different enzyme transforms sugar into a new compound, adding to the complexity of the chemical structure.
In the past, scientists relied on yeast for only the final steps, fabricating the opiates from the compounds created at the intermediate steps.
Scientists have known that yeast could also make the early stages of the process more efficient, but they’ve never isolated the right enzyme to make it work. At that stage, a compound is required called L-dopa, which is made by the enzyme tyrosine hydroxlase. Despite years of searching, scientists had never found a version of the tyrosine hydroxylase enzyme in plants, animals or bacteria that could work in yeast. And using yeast in both the early and late stages of the process would simplify the process.