Substrate specificities of farnesyl diphosphate synthases of Bacillus stearothermophilus and porcine liver with allylic substrate homologs having vinyl or ethynyl group

Abstract

To investigate substrate specificities of farnesyl diphosphate synthases from porcine liver and Bacillus stearothermophilus, we have examined the reactivities of vinyldimethylallyl and ethynyldimethylallyl diphosphates as allylic substrate homologs. The reaction of vinyldimethylallyl diphosphate with isopentenyl diphosphate by farnesyl diphosphate synthase of porcine liver gave vinylgeranyl and vinylfarnesyl diphosphates, which shows that the reaction stopped at the single or double condensation of isopentenyl diphosphate, respectively. However, the similar reaction by the use of wild-type farnesyl diphosphate synthase of B. stearothermophilus gave vinylfarnesyl diphosphate, exclusively. On the other hand, the reaction of Z-ethynyldimethylallyl diphosphates with isopentenyl diphosphate by the use of wild-type of farnesyl diphosphate synthase of B. stearothermophilus gave Z-ethynylfarnesyl diphosphate, as the sole product. Moreover, a mutated farnesyl diphosphate synthase (Y81D) reaction of Z-ethynyldimethylallyl diphosphates with isopentenyl diphosphate gave three kinds of products: ethynylgeranyl, ethynylfarnesyl, and ethynylgeranylgeranyl diphosphates. Using wild-type of farnesyl diphosphate synthase of B. stearothermophilus, the reaction of E-ethynyldimethylallyl diphosphate with isopentenyl diphosphate gave only E-ethynylfarnesyl diphosphate as double condensation product.