Con A recognizes α-linked mannose present as part of a “core oligosaccharide” in many serum and membrane glycoproteins. Fluorescein labeled Con A 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 495 nm and the emission maximum is at 515 nm.