Evans W H, Hardison W G
Biochem J. 1985 Nov 15;232(1):33-6. doi: 10.1042/bj2320033.
The composition of hepatic endosome subfractions was compared directly with that of plasma membranes and Golgi-apparatus fractions. The neutral lipid and phospholipid composition of two endosome subfractions separated on Nycodenz gradients from a parent endosome fraction was similar to that of plasma membranes. The phospholipid/cholesterol ratios and the sphingomyelin contents were high, as in plasma membranes. However, the phosphatidylserine content was low. Endosomal subfractions contained a simpler polypeptide profile than did plasma membranes. However, a large number of glycoproteins were common to both fractions. Two endosome-specific glycoproteins, of Mr 59 000 and 38 000, were identified. Sialic acid was present at concentrations higher than in plasma membranes. The results indicate that endosomal membranes have a similar composition to plasma membranes that probably reflects their functional interaction during endocytosis and receptor recycling.
将肝内体亚组分的组成与质膜和高尔基体组分的组成直接进行了比较。从母本内体组分通过 Nycodenz 梯度分离得到的两个内体亚组分的中性脂质和磷脂组成与质膜相似。磷脂/胆固醇比率和鞘磷脂含量较高，与质膜情况相同。然而，磷脂酰丝氨酸含量较低。内体亚组分的多肽谱比质膜的更简单。不过，两个组分都有大量糖蛋白。鉴定出两种内体特异性糖蛋白，分子量分别为 59000 和 38000。唾液酸的浓度高于质膜。结果表明，内体膜的组成与质膜相似，这可能反映了它们在胞吞作用和受体循环过程中的功能相互作用。
