摘要
用生物膜的拆离与重建方法将从牛脑皮层膜中纯化的激活型ＧＴＰ结合蛋白（Ｇｓ）和腺苷酸环化酶（ＡＣ）在含有不同极性头部或不同脂肪酸侧链的磷脂组成的脂质体上重建形成脂酶体，测定脂酶体中ＡＣ的基础活力及Ｇｓ激活ＡＣ的活力。实验结果表明，磷脂影响ＡＣ的基础活力和Ｇｓ激活ＡＣ活力的顺序依次为：ＰＥ＞ＰＳ＞ＰＣ；含不同脂肪酸侧链的混合磷脂对Ｇｓ的激活活力的影响大于含单一脂肪酸侧链的纯磷脂，如ＰＥＤＰＰＥ，ＰＳＤＰＰＳ，ＰＣＤＰＰＣ。含不同脂肪酸侧链的磷脂影响Ｇｓ的活力的顺序为ＤＬＰＣ＞ＤＭＰＣ＞ＤＰＰＣ。用反映磷脂分子的堆积程度的荧光探剂ＭＣ５４０和脂双层的流动性变化的ＤＰＨ以及专一性标记蛋白质巯基（－ＳＨ）基团的荧光探剂ａｃｒｙｌｏｄａｎ的测定结果表明，不同磷脂影响Ｇｓ的活力的差异主要是由于脂质物理状态的不同所致。
Stimulated GTP - binding protein (Q) and adenylyl cyclase (AC) from bovine brain conices were co - reconstituted into liposomes made of different headgroups or different acyl chain composition. The hasal activity of AC and Gs stimulated AC activity were measured. The order of effectiveness of headgroups of phospholipids on the hasal and Gs stimulated activity of adenylyl cyclase is: PE > PS > PC, and the order of the effectiveness for acyl chain composition is: DLPC > DMPC > DPPC. The results also show that phospholipids with mixed fatty acid chain have stronger effect on the activity of Gs stimulation than phospholipids with dipalmitoyl - chain, that is PE > DPPE, PS > DPPS, PC > DPPC. From the results of the measurements of fluorescent probes MC540, DPH and acrylodan, it is suggested that the physical state change of lipid bilayer may mediate the conformation of Gs with higher activity.
出处
《生物物理学报》
CAS
CSCD
北大核心
1996年第4期597-602,共6页
Acta Biophysica Sinica
关键词
生物膜
膜脂
物理状态
G-蛋白
腺苷酸环化酶
Stimulated GTP - binding protein (G_s) Reconstitution Physical state of membrane Conformation
