Differential binding of proteins to peroxisomes in rat hepatoma cells: unique association of enzymes involved in isoprenoid metabolism
Sita D. Gupta; Ryan S. Mehan; Terese R. Tansey; Hua-Tang Chen; Gertrud Goping; Israel Goldberg; and Ishaiahu Shechter
11/30/2013
LIPD Research
Farnesyl diphosphate synthase (FPPS: EC2.5.1.10), a key enzyme in isoprenoid metabolic pathways, catalyzes the synthesis of farnesyl diphosphate (FPP) an intermediate in the biosynthesis of both sterol and non-sterol isoprenoid end products. The localization of FPPS to peroxisomes has been reported (Krisans, S. K., J. Ericsson, P. A. Edwards, and G. A. Keller. 1994. J. Biol. Chem. 269: 14165–14169). Using indirect immunofluorescence and immunoelectron microscopic techniques we show here that FPPS is localized predominantly in the peroxisomes of rat hepatoma H35 cells. However, the partial release of 60–70% of cellular FPPS activity is observed by selective permeabilization of these cells with digitonin. Under these conditions, lactate dehydrogenase, a cytosolic enzyme, is completely released whereas catalase, a known peroxisomal enzyme, is fully retained. Digitonin treatment of H35 cells differentially affects the release of other peroxisomal enzymes involved in isoprenoid metabolism.