Cell membranes and multilamellar vesicles: Influence of pH on solvent induced damage
Cell membranes and multilamellar vesicles: Influence of pH on solvent induced damage
复制标题
细胞膜和多层囊泡：pH 对溶剂诱导损伤的影响
作者：
M. K. Jacobsohn;M. Lehman;G. Jacobsohn
从绵羊和马的红细胞和红甜菜组织诱导的非极性溶剂的色素泄漏被确定为pH值的函数。结果进行了比较，以破坏的多层囊泡（MLV）组成的磷脂与等摩尔的胆固醇在相同的条件下的溶剂暴露和pH值。MLV由1，2-二油酰磷脂酰乙醇胺鞘磷脂（SP）和各种磷脂酰胆碱制成，以模拟膜的主要脂质组分。石油烃（沸点60-80°C）引起的红细胞色素渗漏在pH 2-4和pH 10时最大，但在pH 6.8时最小;酒精引起的色素渗漏比石油烃少。石油烃诱导的甜菜组织中甜菜花青苷渗漏在pH 2时最大，在pH 4、6.6和pH 10时渗漏非常小。酒精对甜菜组织的损害最小，pH值高于2。石油烃从混合脂质组合物的MLV中去除胆固醇在pH 2-4时最大，在pH 6.8时降低，在pH 10时最小。其中一种磷脂的脂肪酰基侧链具有不同长度的脂质混合物比其中酰基侧链具有相同链长的混合物损失更多的甾醇。MLV与超过25%的SP失去了更多的甾醇比那些少或没有SP。结果表明，在磷脂的混合物中，SP暴露的烃相的双层溶剂萃取，也观察到在原生膜的属性。含有SP的红细胞膜比没有SP的甜菜细胞受到石油烃更严重的破坏。从红细胞膜更容易在pH值10比MLV溶剂破坏，但他们更耐在生理pH值。这表明，由于在pH值的变化引起的膜蛋白的构象变化暴露周围脂质的疏水部分的环境。在中性pH下，预期蛋白质的天然构象稳定膜的双层。
Pigment leakage from sheep and horse erythrocytes and from red beet tissue induced by non-polar solvents was determined as a function of pH. The results were compared to disruption of multilamellar vesicles (MLV) composed of phospholipids with equimolar cholesterol under identical conditions of solvent exposure and pH. Solvent access to cholesterol was used to measure vesicle disruption. MLV were made from 1,2-dioleoyl phosphatidylethanolamine sphingomyelin (SP) and various phosphatidylcholines to simulate the major lipid components of membranes. Pigment leakage from erythrocytes caused by petroleum hydrocarbon (b.p. 60–80°C) was maximal at pH 2–4 and at pH 10, but minimal at pH 6.8; alcohols caused less pigment leakage than petroleum hydrocarbon. Betacyanin leakage from beet tissue induced by petroleum hydrocarbon was maximal at pH 2, with very little leakage at pH 4, 6.6 and pH 10. Alcohols caused minimal damage to beet tissue above pH 2. Cholesterol removal by petroleum hydrocarbon from MLV of mixed lipid composition was maximal at pH 2–4, reduced at pH 6.8 and minimal at pH 10. Lipid mixtures in which fatty acyl side chains of one phospholipid were of a different length than the other lost more sterol than mixtures in which the acyl side chains were of identical chain length. MLV with more than 25% SP lost more sterol than those with less or no SP. Results show that in mixtures of phospholipids, SP exposes the hydrocarbon phase of a bilayer to solvent extraction, a property that was also observed in native membranes. Erythrocyte membranes, which contain SP, were more severely damaged by petroleum hydrocarbon than beet cells, which have none. Membranes from erythrocytes were more prone to solvent disruption at pH 10 than MLV, but they were more resistant at physiological pH. It is suggested that conformational changes in membrane proteins due to shifts in pH cause exposure of hydrophobic portions of surrounding lipids to the environment. At neutral pH, the native conformation of proteins is expected to stabilize the bilayer of membranes.
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由二油酰磷脂酰乙醇胺和油酸组成的血浆稳定脂质体的表征[已发表的错误出现在 Biochem Biophys Res Commun 1989 Sep 29;163(3):1539]。
DOI：
10.1016/0006-291x(89)91999-2
发表时间：
1989
影响因子：
3.1
作者：
Liu,DX;Zhou,F;Huang,L
通讯作者：
Huang,L
DOI：
10.1073/pnas.86.15.5825
发表时间：
1989-08
影响因子：
11.1
作者：
S. Hui;Arindam Sen
通讯作者：
S. Hui;Arindam Sen
影响因子：
2.9
作者：
M. Sankaram;T. E. Thompson
通讯作者：
M. Sankaram;T. E. Thompson
影响因子：
2.9
作者：
RAND, RP;FULLER, NL;PARSEGIAN, VA
通讯作者：
PARSEGIAN, VA
鞘磷脂和磷脂酰胆碱与荧光脱氢麦角甾醇的相互作用。
影响因子：
2.9
作者：
Schroeder,F;Nemecz,G
通讯作者：
Nemecz,G