Carmel G, Rodrigue F, Carrière S, Le Grimellec C
Biochim Biophys Acta. 1985 Aug 27;818(2):149-57. doi: 10.1016/0005-2736(85)90557-7.
Lipid composition, physical state of major phospholipid classes and transbilayer migration of phosphatidylcholine have been determined in plasma membranes of the dog kidney. The lipid composition of brush-border membranes markedly differs from that of antiluminal membranes with respect to: (a) the total phospholipid content; (b) the cholesterol to phospholipid ratio (C/P); (c) the distribution of the major phospholipid classes. Sphingomyelin present in large amounts in both luminal and antiluminal membranes extracts exhibits a transition of phase between 20 and 44 degrees C approximately. In the range of temperature studied (5-55 degrees C) no phase transitions were detected for the other phospholipid species. Our data suggest that: (1) at physiological temperature the higher C/P ratio of brush-border membranes is in large part responsible for their lower fluidity; (2) both the relatively low cholesterol and high sphingomyelin contents contribute to the thermotropic transitions observed in intact membranes. Finally transbilayer migration of phosphatidylcholine in brush-border membranes is a very slow process with a half time of 6.5 h at 37 degrees C which compares with that of other biological membranes.
已对犬肾细胞膜中的脂质组成、主要磷脂类别的物理状态以及磷脂酰胆碱的跨膜迁移进行了测定。刷状缘膜的脂质组成在以下方面与抗腔面膜明显不同：(a) 总磷脂含量；(b) 胆固醇与磷脂的比率（C/P）；(c) 主要磷脂类别的分布。在管腔膜和抗腔膜提取物中大量存在的鞘磷脂在大约20至44摄氏度之间呈现相转变。在所研究的温度范围（5 - 55摄氏度）内，未检测到其他磷脂种类的相转变。我们的数据表明：(1) 在生理温度下，刷状缘膜较高的C/P比率在很大程度上导致其较低的流动性；(2) 相对较低的胆固醇含量和较高的鞘磷脂含量都有助于在完整膜中观察到的热致转变。最后，刷状缘膜中磷脂酰胆碱的跨膜迁移是一个非常缓慢的过程，在37摄氏度下半衰期为6.5小时，这与其他生物膜的情况相当。
