Nature Chem. Biol. doi:10.1038/nchembio.117 (2008)

'Promiscuous' chemicals that can inhibit two different classes of enzymes could aid in the design of new cancer therapies.

Kevan Shokat of the University of California, San Francisco, and his colleagues screened a library of substances, hunting for any that block both tyrosine kinases and phosphatidylinositol-3-OH kinases — enzymes that cancer drugs in development often target.

Two inhibitors fitted the bill. They belong to a category of chemicals called pyrazolopyrimidines and seem to work by interacting chemically with several amino acids that are conserved across the two enzyme classes. Variations in a 'gatekeeper' amino acid apparently prevented the inhibitors acting on other kinds of kinase.