Dabrowska A, Terlecki G, Czapińska E, Gutowicz J
Department of Biochemistry, Wrocław University of Medicine, Poland.
Biochim Biophys Acta. 1995 Jun 14;1236(2):299-305. doi: 10.1016/0005-2736(95)00061-7.
The interaction between bovine heart pyruvate kinase and liposomes was investigated for various phospholipids as function of pH, and salt concentration using steady-state kinetics and ultracentrifugation. Liposomes made from erythrocyte total lipid fraction and individual phospholipids were used. Pyruvate kinase specific activity increases upon the interaction with the phospholipids. The activation is specifically sensitive to presence of phosphatidylserine in liposomes. L-serine, and phospho-L-serine which are main components of phosphatidylserine head group show also some activation effect. Efficient adsorption of pyruvate kinase to phosphatidylserine liposomes occurs in the pH range 6.0-8.0 and at low ionic strength. Interaction with phosphatidylserine liposomes results in the change of Vmax and Km values for phospho enol pyruvate without marked effect on Km value for ADP, and Hill coefficients for both substrates. The interaction does not seem to influence the cooperativity between binding sites.
利用稳态动力学和超速离心法,研究了牛心丙酮酸激酶与脂质体之间的相互作用,该相互作用是多种磷脂在不同pH值和盐浓度下的函数关系。使用了由红细胞总脂质组分和单个磷脂制成的脂质体。丙酮酸激酶与磷脂相互作用后,其比活性增加。这种激活对脂质体中磷脂酰丝氨酸的存在特别敏感。磷脂酰丝氨酸头部基团的主要成分L-丝氨酸和磷酸-L-丝氨酸也显示出一定的激活作用。丙酮酸激酶在pH值6.0 - 8.0范围内和低离子强度下能有效吸附到磷脂酰丝氨酸脂质体上。与磷脂酰丝氨酸脂质体相互作用会导致磷酸烯醇丙酮酸的Vmax和Km值发生变化,而对ADP的Km值和两种底物的希尔系数没有显著影响。这种相互作用似乎不影响结合位点之间的协同性。