Kessels J M, Ousen H, van den Bosch H
Eur J Biochem. 1984 Feb 1;138(3):543-9. doi: 10.1111/j.1432-1033.1984.tb07949.x.
Solubilized glycerophosphate acyltransferase from Escherichia coli was reconstituted in small unilamellar vesicles consisting of phosphatidylcholine/phosphatidylglycerol in a molar ratio of 4:1. Glycerol 3-phosphate, trapped inside these vesicles, cannot be acylated by the enzyme upon addition of extra-vesicular palmitoyl-CoA. Thus, substrate-binding sites and active sites are asymmetrically oriented in the model membrane. When up to 10 mol/100 mol lysophosphatidic acid was incorporated in the vesicles a decrease in glycerophosphate acyltransferase activity is observed at amounts exceeding 1 mol% lysophosphatidate. Similar experiments, using lysophosphatidylcholine and phosphatidic acid, suggest the decrease to result from an increase in negative surface charge. Reconstituted glycerophosphate acyltransferase exhibits a preference for palmitoyl-CoA over oleoyl-CoA. This preference increases considerably at elevated temperatures. The glycerophosphate acyltransferase could, therefore, participate in the temperature-dependent changes in the fatty acid composition of the phospholipids in E. coli.
将来自大肠杆菌的可溶性甘油磷酸酰基转移酶重组到由摩尔比为4:1的磷脂酰胆碱/磷脂酰甘油组成的小单层囊泡中。被困在这些囊泡内的甘油3-磷酸，在添加囊泡外的棕榈酰辅酶A时不能被该酶酰化。因此，底物结合位点和活性位点在模型膜中呈不对称取向。当向囊泡中掺入高达10 mol/100 mol的溶血磷脂酸时，在溶血磷脂酸含量超过1 mol%时观察到甘油磷酸酰基转移酶活性降低。使用溶血磷脂酰胆碱和磷脂酸进行的类似实验表明，这种降低是由于表面负电荷增加所致。重组的甘油磷酸酰基转移酶对棕榈酰辅酶A的偏好超过油酰辅酶A。在升高的温度下，这种偏好会显著增加。因此，甘油磷酸酰基转移酶可能参与大肠杆菌中磷脂脂肪酸组成的温度依赖性变化。
