Dual role of free fatty acids in regulation of mitochondrial L-glycerol-3-phosphate dehydrogenase.

In brown adipose tissue mitochondria, the influence of free fatty acids on FAD-linked L-glycerol-3-phosphate dehydrogenase was investigated using either hydrophilic or hydrophobic electron acceptors. The apparent kinetic parameters were determined for substrate and electron acceptors in the presence of different concentrations of oleic acid. In contrast to the L-glycerol-3-phosphate dehydrogenase enzyme from mitochondrial hyperthyroid rat liver, the brown adipose tissue enzyme shows only a single detectable L-glycerol-3-phosphate binding site. The inhibition is of competitive type for L-glycerol-3-phosphate using either hydrophilic or hydrophobic electron acceptors, while for electron acceptors non-competitive or uncompetitive inhibition was determined, respectively.