Lunney J, Ashwell G
Proc Natl Acad Sci U S A. 1976 Feb;73(2):341-3. doi: 10.1073/pnas.73.2.341.
Evidence is reported to support the following conclusions: (i) The presence of a specific hepatic receptor capable of recognizing and binding galactose-terminated glycoproteins is responsible for maintaining near zero levels of circulating asialoglycoproteins in mammalian serum. (ii) The absence of this galactose-specific binding protein in avian, and presumably reptilian, liver is correlated with high levels of circulating asialoglycoproteins in the serum of these species. (iii) The evolutionary significance of these observations is reinforced by the recognition of an avian hepatic binding protein specific for terminal, N-acetyl-glucosamine residues on glycoproteins.
(i)存在一种能够识别并结合半乳糖末端糖蛋白的特异性肝受体,这使得哺乳动物血清中循环的去唾液酸糖蛋白水平维持在接近零的水平。(ii)禽类以及可能还有爬行类动物的肝脏中缺乏这种半乳糖特异性结合蛋白,这与这些物种血清中高水平的循环去唾液酸糖蛋白相关。(iii)对一种特异性识别糖蛋白上末端N - 乙酰葡糖胺残基的禽类肝结合蛋白的认识,进一步强化了这些观察结果在进化上的意义。