PRENYLTRANSFERASE

The prenyltransferase reaction is reviewed with an emphasis on the enzyme farnesyl pyrophosphate synthetase. Substrate-binding studies have shown that this dimeric enzyme has two catalytic sites with identical substrate specificity. The product farnesyl pyrophosphate is associated with the allylic portion of the catalytic site and overlaps into the homoallylic site, thus interfering with the binding of isopentenyl pyrophosphate. The enzyme also catalyzes a pyrophosphate-stimulated solvolysis of the allylic substrate. This observation, along with studies of the reactivity of fluorine-containing substrate analogues, indicates an ionization-condensation-elimination mechanism for the prenyl transfer reaction. A model showing how the substrates are aligned in the catalytic site is presented. © 1979, Walter de Gruyter. All rights reserved.