Background: Lectins are proteins or glycoproteins of non-immune origin which bind specifically but reversibly to carbohydrates or glycoconjugates. They play a crucial role in various biological processes including host defense mechanism, inflammation and metastasis. Therefore, there is an expanding scientific emphasis on purification and characterization of novel lectins possessing different useful biological properties.

Objective: The present investigation is concerned with purification and characterization of a novel lectin from the hemolymph of oak tasar (Antheraea proylei J.) silkworm.

Methods: The lectin was purified from the hemolymph by a procedure involving successive steps of hemocyte-free hemolymph preparation, ammonium sulfate (0-40%) fractionation and affinity chromatography on a column of Sephadex G-50 covalently coupled with L-rhamnose. It was then characterized by various physico-chemical methods including SDS-PAGE, gel filtration, hemagglutination assay, hemagglutination inhibition assay and tandem mass spectrometry (LCMS/ MS) coupled with Mascot sequence matching software (Matrix Science).

Results: The lectin was purified to electrophoretic homogeneity from the silkworm hemolymph and was found to be a monomeric protein with a native molecular weight of 39.5 kDa. It was specifically inhibited by L-rhamnose and D-fucose, the former being sixteen times more inhibitory than the latter. The hemagglutinating activity was further characterized by independency of metal ion, optimum at pH 7-7.5 and thermal stability with t1/2 of 60°C. Analysis with tandem mass spectrometry coupled with Mascot sequence matching software confirmed the purified lectin to be a protein not purified and characterized earlier.

Conclusion: A novel rhamnose/fucose-specific lectin was purified to electrophoretic homogeneity from the hemolymph of oak tasar (Antheraea proylei J.) silkworm. The lectin was found to be a monomeric protein with a native molecular weight of 39.5 kDa. Its activity was found to be independent of metal ion, optimum at pH 7-7.5 and characterized by thermal stability with t1/2 of 60°C. Analysis with tandem mass spectrometry coupled with Mascot sequence matching software confirmed the purified lectin to be a protein not characterized earlier.

背景：凝集素是非免疫起源的蛋白质或糖蛋白，可特异性但可逆地与碳水化合物或糖缀合物结合。它们在包括宿主防御机制，炎症和转移在内的各种生物学过程中起着至关重要的作用。因此，对具有不同有用生物学特性的新型凝集素的纯化和表征的科学关注日益扩大。

目的：本研究涉及从橡树oak（Antheraea proylei J.）家蚕的血淋巴中提炼出一种新型凝集素。

方法：通过以下步骤从血淋巴中纯化凝集素：该步骤包括无血细胞血淋巴制备，硫酸铵（0-40％）分馏和亲和色谱法在Sephadex G-50与L-鼠李糖共价色谱柱上的连续步骤。然后通过多种物理化学方法对其进行表征，包括SDS-PAGE，凝胶过滤，血凝测定，血凝抑制测定和串联质谱分析（LCMS / MS），以及Mascot序列匹配软件（Matrix Science）。

结果：从家蚕的血淋巴中纯化出的凝集素具有电泳均一性，被发现是天然分子量为39.5 kDa的单体蛋白。它被L-鼠李糖和D-岩藻糖特异性抑制，前者的抑制作用是后者的十六倍。血凝活性的特征还在于金属离子的独立性，最适pH 7-7.5，热稳定性，t1 / 2为60°C。串联质谱结合Mascot序列匹配软件进行的分析证实，纯化的凝集素是未纯化和较早表征的蛋白质。

结论：从橡树tasar（Antheraea proylei J.）家蚕的血淋巴中纯化了一种新的鼠李糖/岩藻糖特异性凝集素，以实现电泳均质。发现该凝集素是天然分子量为39.5kDa的单体蛋白。发现其活性与金属离子无关，最适于pH 7-7.5，并且具有t1 / 2为60°C的热稳定性。串联质谱联用Mascot序列匹配软件进行分析，证实纯化的凝集素是一种较早未鉴定的蛋白质。