Luzio J P, Stanley K K
Biochem J. 1983 Oct 15;216(1):27-36. doi: 10.1042/bj2160027.
Intracellular 5'-nucleotidase involved in membrane circulation in rat hepatocytes is latent, and is protected from inhibition when whole cells are incubated with inhibiting antiserum at 2 degrees C [Stanley, Edwards & Luzio (1980) Biochem. J. 186, 59-69]. These two criteria were used to identify intracellular membrane vesicles containing 5'-nucleotidase on Ficoll density gradients. A sharply defined turbid band containing intracellular 5'-nucleotidase isolated on density gradients was further fractionated by immunoadsorption of plasma-membrane fragments derived from the cell surface of surface-inhibited cells on to an anti-(immunoglobulin G) immunoadsorbent. The resulting non-adsorbed membrane fraction consisted of vesicles of uniform size (approx. 65 nm diam.), but was not identifiable as any known organelle. This fraction could account for approx. 5% of the total cell 5'-nucleotidase activity, and the enzyme activity measured was 55% latent. The fraction had a restricted polypeptide composition but similar phospholipid composition compared with plasma membrane. We suggest that the vesicles observed in this fraction were derived from the endocytic pathway.
参与大鼠肝细胞内膜循环的细胞内5'-核苷酸酶是潜伏性的，当全细胞在2℃下与抑制性抗血清一起孵育时，该酶可免受抑制作用[斯坦利、爱德华兹和卢齐奥（1980年）《生物化学杂志》186卷，59 - 69页]。利用这两个标准在Ficoll密度梯度上鉴定含有5'-核苷酸酶的细胞内膜泡。通过将源自表面受抑制细胞表面的质膜片段免疫吸附到抗（免疫球蛋白G）免疫吸附剂上，对在密度梯度上分离得到的含有细胞内5'-核苷酸酶的清晰界定的浑浊带进行进一步分级分离。所得的未吸附膜部分由大小均匀（直径约65nm）的泡组成，但无法鉴定为任何已知的细胞器。该部分约占细胞总5'-核苷酸酶活性的5%，所测得的酶活性有55%是潜伏性的。与质膜相比，该部分的多肽组成有限，但磷脂组成相似。我们认为在该部分观察到的泡源自内吞途径。
