Substrate specificity of recombinant Arabidopsis PGGT I. Quantitative filter assay data are shown for recombinant Arabidopsis PGGT I in the presence of [1-3H]FPP, [1-3H]GGPP, and 32 distinct CaaX substrates. The CaaX substrates are grouped with the variable amino acid indicated in red. Asterisks indicate PGGT1-catalyzed protein farnesylation detectable after 4 days by SDS-PAGE and fluorography. The red line indicates background. The standard error of the mean is shown.