Wheat Germ Agglutinin (WGA) Conjugates
Wheat germ agglutinin (WGA) is a carbohydrate-binding lectin originally derived from Triticum vulgare. Like other lectins, such as Concanavalin A (ConA), WGA exhibits a high binding affinity for distinct sugar residues commonly present on cell-surface and intracellular glycoconjugates (e.g., glycoproteins and glycolipids). This specificity is often exploited in fluorescence imaging and analysis techniques to label the plasma membranes of eukaryotic cells, gram-positive bacteria, and yeast bud scars, stain fibrotic scar tissue, and localize and detect glycosylated proteins in gels. Fluorescent WGA conjugates, including those labeled with bright, photostable iFluor® dyes, provide greater flexibility in designing colocalization and other multicolor experiments for imaging and flow cytometry.
Properties of Wheat Germ Agglutinin
Wheat germ agglutinin selectively binds to N-acetylglucosaminyl (GlcNAc) and N-acetylneuraminic acid (sialic acid) residues on glycoconjugates and oligosaccharides found throughout the cell surface. The presence and distribution of these residues can not only vary among cell and organelle types but can also be expressed abnormally in various pathologies, making WGA a useful marker in identifying and profiling These phenotypes. WGA is water-soluble and, in solution, exists primarily as a heterodimer with a molecular weight of ∼38 kDa. Under physiological conditions, WGA is cationic (pl > 9) and unable to penetrate live cells. Cell and tissue samples must be fixed before staining with fluorescent WGA conjugates to detect intracellular glycoconjugates and oligosaccharides.
When succinylated with succinic anhydride, the solubility of WGA increases 100-fold at neutral pH and can agglutinate rabbit and human erythrocytes (A, B, and O blood types) with a minimum concentration of 2 µg/mL. Like unmodified WGA, succinylated WGA is specific for GlcNAc residues. However, it loses its binding affinity for sialic acid residues suggesting the use of both lectins as a system for distinguishing between N-acetylglucosaminylated and sialylated glycoconjugates.
Fluorescent WGA conjugates are commonly used in imaging and flow cytometry to localize and detect cell-surface or intracellular glycoconjugates. They are useful at identifying cell types based on glycoprotein-makeup and for labeling eukaryotic cell walls, fibrotic scar tissue, yeast bud scars, chitin and bacterial cell wall peptidoglycans. The latter has been used to differentiate gram-positive and gram-negative bacteria.
Fluorescent iFluor®-WGA Conjugates

Live HeLa cells were stained with iFluor® 488-Wheat Germ Agglutinin (WGA) Conjugate at 5 µg/mL for 30 minutes followed by Hoechst 33342 (Cat No. 17535). Image was acquired using fluorescence microscopy using FITC and DAPI filter set.
Table 1. Fluorescent wheat germ agglutinin conjugates and their spectral properties
Product ▲ ▼ | Ex (nm) ▲ ▼ | Em (nm) ▲ ▼ | Unit Size ▲ ▼ | Cat. No. ▲ ▼ |
iFluor® 488-WGA Conjugate | 491 | 516 | 1 mg | 25530 |
iFluor® 555-WGA Conjugate | 557 | 570 | 1 mg | 25539 |
iFluor® 594-WGA Conjugate | 588 | 604 | 1 mg | 25550 |
iFluor® 647-WGA Conjugate | 656 | 670 | 1 mg | 25559 |
Wheat Germ Agglutinin, XFD488 Labeled *XFD488 Same Structure to Alexa Fluor™ 488* | 499 | 520 | 1 mg | 25500 |
Wheat Germ Agglutinin, XFD594 Labeled *XFD594 Same Structure to Alexa Fluor™ 594* | 590 | 618 | 1 mg | 25509 |