Effect of fatty acid binding proteins on developing human placental malate dehydrogenase activity

Role of fatty acid binding proteins (FABPs) in modulating inhibition of human placental malate dehydrogenase by palmitoyl-CoA and oleate has been studied. Activity of human placental cytosolic malate dehydrogenase is detected throughout the gestation, showing a peak at midgestation (20-25 weeks). Inhibition (50%) of the enzyme activity is obtained by 20 microM palmitoyl-CoA or 35 microM oleate. FABPs enhance the activity of malate dehydrogenase in absence of palmitoyl-CoA or oleate and also protect against palmitoyl-CoA or oleate inhibition. Such a modulatory effect of FABP may be due to the binding of long chain fatty acyl-CoA or fatty acid rather than a direct effect of FABPs on the enzyme.