Cammue B, Stinissen H M, Peumans W J
Eur J Biochem. 1985 Apr 15;148(2):315-22. doi: 10.1111/j.1432-1033.1985.tb08841.x.
Extracts from couch grass (Agropyrum repens) leaves contain relatively high lectin concentrations. Preliminary experiments with crude extracts indicated that the leaf lectin differs from the embryo lectin of the same species and other Gramineae embryo lectins with respect to its sugar and blood group specificity, and serological properties. A comparison of the biochemical, physicochemical and biological properties of purified lectins from couch grass leaves and embryos, and wheat germ agglutinin revealed that the leaf lectin has the same molecular structure as the embryo lectins. It is a dimer composed of two identical subunits, which, however, are slightly larger than embryo lectin subunits. Structural differences between both couch grass lectins were further inferred from in vitro subunit exchange experiments and serological analyses. Whereas the embryo lectin readily forms heterodimers with embryo lectins from other cereal species and also is serologically indistinguishable from them, the leaf lectin does not exchange subunits with the same embryo lectins and is serologically different. In addition, couch grass leaf lectin exhibits specificity for N-acetylgalactosamine and agglutinates preferentially blood-group-A erythrocytes whereas the embryo lectin is not inhibited by N-acetylgalactosamine and exhibits no blood-group specificity. It was observed also that the lectin content of couch grass leaves varies enormously during the seasons.
匍匐冰草（Agropyrum repens）叶片提取物中凝集素浓度相对较高。对粗提物进行的初步实验表明，叶片凝集素在糖和血型特异性以及血清学特性方面，与同一物种的胚凝集素和其他禾本科植物的胚凝集素不同。对匍匐冰草叶片和胚中的纯化凝集素以及麦胚凝集素的生化、物理化学和生物学特性进行比较后发现，叶片凝集素与胚凝集素具有相同的分子结构。它是由两个相同亚基组成的二聚体，不过这两个亚基比胚凝集素的亚基略大。通过体外亚基交换实验和血清学分析进一步推断出两种匍匐冰草凝集素之间的结构差异。胚凝集素很容易与其他谷类物种的胚凝集素形成异源二聚体，并且在血清学上与它们无法区分，而叶片凝集素不会与相同的胚凝集素进行亚基交换，并且在血清学上有所不同。此外，匍匐冰草叶片凝集素对N - 乙酰半乳糖胺具有特异性，优先凝集A型血红细胞，而胚凝集素不受N - 乙酰半乳糖胺抑制，且不表现出血型特异性。还观察到，匍匐冰草叶片中的凝集素含量在不同季节变化极大。
