The design and function of A synthetic "chemical transducer" that can generate an unnatural communication channel between two proteins is described. Specifically, we show how this transducer enables platelet-derived growth factor to trigger (in vitro) the catalytic activity of glutathione-s-transferase (GST), which is not Its natural enzyme partner. GST activity can be further controlled by adding specific oligonucleotides that switch the enzymatic reaction: on and off: We also demonstrate that a molecular machine, which can regulate the function of an enzyme, could be used to change the way a prodrug is activated in a "programmable" manner.