Duncan R, Starling D, Rypácek F, Drobník J, Lloyd J B
Biochim Biophys Acta. 1982 Aug 6;717(2):248-54. doi: 10.1016/0304-4165(82)90176-3.
Incorporation of 20% tyramine residues into its structure greatly increased the rate of pinocytosis of poly(alpha, beta-(N-2-hydroxyethyl))-DL-aspartamide (PHEA) by rat visceral yolk sacs cultured in vitro. Both the parent macromolecule and the tyramine derivative (PHEA-tyramine) were captured by adsorptive pinocytosis, the higher affinity of the derivative for the yolk sac plasma membrane being responsible for its greater rate of capture. Using 125I-labelled PHEA-tyramine, the relationship between substrate concentration and rate of capture was determined, it was also shown that following internalization, the PHEA-tyramine linkage is resistant to intracellular hydrolysis. Fluorescence micrographs were consistent with capture of both substrates being by pinocytosis and illustrated the highly efficient concentration of the tyramine derivative by yolk sac endodermal cells.
将20%的酪胺残基引入其结构中，极大地提高了体外培养的大鼠内脏卵黄囊对聚（α，β-（N-2-羟乙基））-DL-天冬酰胺（PHEA）的胞饮速率。母体大分子和酪胺衍生物（PHEA-酪胺）均通过吸附性胞饮作用被摄取，衍生物对卵黄囊质膜的更高亲和力导致其摄取速率更高。使用125I标记的PHEA-酪胺，确定了底物浓度与摄取速率之间的关系，还表明内化后，PHEA-酪胺键对细胞内水解具有抗性。荧光显微照片与两种底物均通过胞饮作用摄取一致，并说明了卵黄囊内胚层细胞对酪胺衍生物的高效浓缩。
