小麦凝集素（Wheat Germ Agglutinin，WGA）从普通小麦（Triticum vulgaris）中分离并经亲和层析纯化得到。该凝集素由两个亚基组成，分子量为36kDa。WGA可选择性结合糖蛋白和糖脂上的N-乙酰葡糖胺（GlcNAc）及N-乙酰神经氨酸（唾液酸）残基，这些结构常存在于细胞膜表面。WGA的受体糖是N-乙酰葡糖胺，优先与这种糖的二聚体和三聚体结合。WGA可以结合含有末端N-乙酰葡糖胺或壳二糖的低聚糖，这些结构在许多血清和膜糖蛋白中很常见。细菌细胞壁肽聚糖、几丁质、软骨糖胺聚糖和糖脂也可以结合WGA。
AF555标记的WGA结合了适当数量的荧光染料，且通过纯化去除未反应的染料，降低其在免疫荧光染色中的背景，为这种凝集素提供了最佳的染色特性。AF555染料激发最大值位于 553 nm，发射最大值位于 568 nm。荧光 WGA 偶联物可对多种细胞类型的质膜进行选择性标记，背景极低；且在经甲醛固定及 Triton X-100 透膜处理后，信号依然保留。
Triticum vulgaris lectin or Wheat germ agglutinin (WGA) is isolated from Triticum vulgaris (Wheat germ) and purified by affinity chromatography. The lectin has two subunits and a molecular weight of 36 kDa. WGA selectively binds to N-Acetyl glucosamine (GlcNAc) and to N-acetylneuraminic acid (sialic acid) residues of glycoproteins and glycolipids, which are often found on cell membranes.
WGA is commonly used to label glycoproteins for imaging of the plasma membrane in live or fixed cells, for staining of tissue sections, or for western blotting. WGA can be used as a gram stain to fluorescently label gram bacteria but not gram- bacteria. WGA also binds to the bud scars on budding yeast such as Saccharomyces cerevisiae.
AF555 labeled WGA has an appropriate number of fluorochromes bound to provide the optimum staining characteristics for this lectin. This conjugate is supplied essentially free of unconjugated fluorochromes.
The excitation maximum is at 553 nm and the emission maximum is at 568 nm. Fluorescent WGA conjugates provide selective labeling of the plasma membrane with minimal background in many cell types that is retained after formaldehyde fixation and permeabilization with Triton X-100.
危险品化学品经营许可证（带存储）