Geranyltranstransferase
![Crystal structure of the FPPS homodimer with IPP and DMAPP analogue, DMSPP (PDB ID: 1RQI). Monomers are shown in magenta and dark blue. Residues in hydrophobic pocket are highlighted in yellow. The base of the pocket is formed by the residue in green (a phenylalanine). A 90 degree rotated monomer structure is shown in Inset 1 to highlight the hydrophobic pocket. A top view of the active site is shown in Inset 2 along with the aspartate mediated trinuclear Mg2+ (silver spheres) catalytic center.[2] Images generated in PyMOL.](/Images/godic/202501/15/Structure_of_FPPS2352.jpg")
![FPPS, a geranyltranstransferase, catalyzes reactions (shown with red arrows) central to many biosynthetic pathways.[6]](/Images/godic/202501/15/FPPS_Biosynthetic_Pathways_Version_22353.png")
In enzymology, a geranyltranstransferase (EC2.5.1.10) is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are geranyl diphosphate (a 10 carbon precursor) and isopentenyl diphosphate (a 5 carbon precursor) whereas its two products are diphosphate and trans,trans-farnesyl diphosphate (a 15 carbon product).