Phosphoinositide-specific phospholipase C-delta 1: effect of monolayer surface pressure and electrostatic surface potentials on activity.
Phosphoinositide-specific phospholipase C-delta 1: effect of monolayer surface pressure and electrostatic surface potentials on activity.
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磷酸肌醇特异性磷脂酶 C-delta 1：单层表面压力和静电表面电位对活性的影响。
DOI：
10.1021/bi00166a006
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发表时间：
1992
期刊：
影响因子：
2.9
通讯作者：
McLaughlin,S
中科院分区：
文献类型：
--
作者：
Rebecchi,M;Boguslavsky,V;Boguslavsky,L;McLaughlin,S
摘要：我们将磷脂酶C-(PLC-)加入到由磷脂酰肌醇4,5 -二磷酸（2% PIP2）、磷脂酰丝氨酸（33% PS）和磷脂酰胆碱（65% PC）混合物组成的单层水亚相中，然后在加入10µ游离钙后测量PIP2的初始水解速率。增加单分子膜的表面压力，从20 ~ 40 mN/m使水解速率降低200倍。水解速率指数取决于表面压力：速率exp （-Tv4p/k T）其中k为玻尔兹曼常数，T为温度，Ap为1nm2 ***。不同（1µ和100µ）的游离[Ca2+]和不同的PIP2摩尔分数得到了类似的结果。结果与一个模型一致，即在没有钙离子的情况下，plc以高亲和力（ATa= 106 M”1）与PIP2结合[Rebecchi， M. J., Peterson, a ., & McLaughlin， S.(1993) Biochemistry（本期之前的论文）]，并且部分plc -面积Ap插入到单层中，在PIP2水解之前做work= irAp。从单层中去除单价酸性脂质PS会使plc -活性降低4倍，这种PS对活性的影响与单层囊泡中单价酸性脂质对plc与PIP2结合的影响相似。
Revised Manuscript Received October 15, 1992 abstract: We added phospholipase C-(PLC-) to the aqueoussubphase beneath monolayers formed from mixtures of phosphatidylinositol 4, 5-bisphosphate (2% PIP2), phosphatidylserine (33% PS), and phosphatidylcholine (65% PC) and then measured the initial rate of hydrolysis of PIP2 after addition of 10 µ free calcium. Increasing the surface pressure of the monolayer,, from 20 to 40 mN/m decreased the rate of hydrolysis 200-fold. The rate of hydrolysis depends exponentially on the surface pressure: rate a exp (-Tv4p/k T) where k is the Boltzmann constant, T is the temperature, and Ap 1 nm2***.Similar results were obtained with different (1 and 100 µ) free [Ca2+] and with different mole fractions of PIP2. The results are consistent with a model in which PLC-binds to PIP2 with high affinity (ATa= 106 M" 1) in the absence of calcium ions [Rebecchi, M. J., Peterson, A., & McLaughlin, S.(1993) Biochemistry (preceding paper in this issue)], and a portion of PLC-of area Ap inserts into the monolayer doing work= irAp prior to hydrolysis of PIP2. Removing the monovalent acidic lipid PS from the monolayer decreases the activity of PLC-4-fold, this effect of PS on activity is similar to the effect of monovalent acidic lipids on the binding of PLC-to PIP2 in bilayer vesicles.