Membrane lateral pressure as a modulator of glycerol-3-phosphate dehydrogenase activity

Michaelis-Menten kinetics of glycerol-3-phosphate dehydrogenase activity in proteoliposomes from brown adipose tissue mitochondria with exogenously added phospholipids or cholesterol was measured. It was shown that changes in membrane lipid composition affected the membrane lateral pressure and therefore modulated the enzyme activity, namely Vmax value. Contrarily, changes in surface charge caused by minute amounts of phosphatidylserine or charged organic substances influenced only the apparent Km value. The role of bulk phospholipids in regulation of glycerol-3-phosphate dehydrogenase is discussed.