Compartmentation of isopentenyl pyrophosphate isomerase and prenyl transferase in developing castor bean endosperm

Abstract

Isopentenyl pyrophosphate isomerase and prenyl transferase are present in the proplastid and mitochondrial fractions of developing castor bean endosperm. Three forms of prenyl transferase have also been separated in extracts of germinating seeds. One of these enzymes, farnesyl transferase, is present in the proplastid. The precise subcellular locations of the other two, geranyl transferases I and II, have not yet been determined. These results are consistent with the proposal that enzyme segregation plays an important role in governing the flow of carbon in isoprenoid pathways.