Primordial Path To Painkillers

Thanks to an enzyme from an ancient microbe, researchers have found new options for making optically pure precursors to familiar painkillers. Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are sold as racemic mixtures, even though their biological activity resides in the S enantiomers. The body can convert R versions of NSAIDs to their S forms, but the process isn't equally efficient for all drugs and may be responsible for some side effects. David B. Berkowitz, Paul Blum, and colleagues at the University of Nebraska, Lincoln, have isolated an alcohol dehydrogenase enzyme from a single-celled Archaea microorganism and used the enzyme to transform racemic aldehyde starting materials to S alcohol NSAID precursors (J. Am. Chem. Soc., DOI: 10.1021/ja910778p). Other routes to the chiral precursors exist, but because the archaeal enzyme is heat-stable, the team used higher temperatures and less solvent than is typically needed, with ethanol as a biorenewable reducing agent. The team collects crystallized products by filtration and recycles the enzyme. The work showcases how useful archaeal enzymes can be in asymmetric synthesis, the researchers point out.