Menghi G, Materazzi G
Department of Biology, University of Camerino, Italy.
Histol Histopathol. 1994 Jan;9(1):173-83.
This review was focused on the salivary gland oligosaccharide chains studied by lectin histochemistry combined with exoglycosidase digestion. Glycoconjugates play an important role in many biofunctions and, generally, salivary mucins, which consist of numerous oligosaccharide chains attached at closely spaced intervals to a peptide backbone, serve as lubricants and protective agents, but in many instances we are ignorant about the role of biochemically identified oligosaccharides. Lectin histochemistry represents the greatest analytic tool to study carbohydrates in situ; in addition, there is availability of selective enzymes, so glycosidase degradation is useful to both investigate the structure of a given oligosaccharide and verify the influence of neighbouring sugars on the affinity towards the respective specific lectins. Using stepwise digestion of samples, followed by lectin labelling, the structure of terminal short oligosaccharides with blood-group activity was also elucidated. Additional histochemical methodologies were developed to establish the presence of acetylated groups in sialic acid residues, and the position of the linkage to the underlying monosaccharide. Sequencing approaches by exoglycosidases and lectins were also seen to be particularly useful when substantial differences did not emerge in lectin affinity, glycoconjugate composition and complex carbohydrate cytochemistry.
本综述聚焦于通过凝集素组织化学结合外切糖苷酶消化研究的唾液腺寡糖链。糖缀合物在许多生物功能中发挥着重要作用，一般来说，唾液粘蛋白由众多以紧密间隔连接到肽主链上的寡糖链组成，充当润滑剂和保护剂，但在许多情况下，我们对生物化学鉴定的寡糖的作用并不了解。凝集素组织化学是研究原位碳水化合物的最强大分析工具；此外，有选择性酶可用，因此糖苷酶降解对于研究给定寡糖的结构以及验证相邻糖对各自特异性凝集素亲和力的影响都很有用。通过对样品进行逐步消化，然后进行凝集素标记，还阐明了具有血型活性的末端短寡糖的结构。还开发了其他组织化学方法来确定唾液酸残基中乙酰化基团的存在以及与潜在单糖的连接位置。当凝集素亲和力、糖缀合物组成和复合碳水化合物细胞化学没有出现实质性差异时，外切糖苷酶和凝集素的测序方法也特别有用。
