We describe a method for the purification of farnesyl:protein transferase, an enzyme that transfers a farnesyl group from farnesyl pyrophosphate to a COOH-terminal cysteine in ras proteins, nuclear lamin B, and the γ subunit of bovine transducin. The enzyme is purified to homogeneity from rat brain cytosol through use of an affinity chromatography step based on the enzyme's ability to specifically bind to a hexapeptide containing the consensus sequence for farnesylation. The purification procedure is reproducible and enables the isolation of microgram amounts of purified enzyme from 50 rat brains. Two methods for assaying enzymatic activity are also described. One assay measures the transfer of [3H]farnesyl from [3H]farnesyl pyrophosphate to recombinant H-ras, and the other measures the transfer of [3H]farnesyl to a biotinylated peptide containing the Cys-AAX COOH-terminal sequence of K-rasB.
ASJC Scopus subject areas
- Molecular Biology
- Biochemistry, Genetics and Molecular Biology(all)