Isoprenyldiphosphate synthases

Isoprenyldiphosphate synthases catalyze consecutive condensations of isopentenyldiphosphates with allylic primer substrates to form linear backbones for all isoprenoid compounds including cholesterol. These synthases are classified according to the final chain length of their end products and the stereochemistry of the newly formed double bonds. Mutagenesis and X-ray crystallography data have uncovered the basic catalytic and chain length determination mechanisms of E-isoprenyldiphosphate synthases and shed light on their possible evolutionary course. Although much less is known about the Z-isoprenyldiphosphate synthase family, successful cloning and subsequent crystallizations in the near future will no doubt bring more insight as researchers begin to unravel the essential components and precise reaction mechanisms of this cellular machinery.