Jacalin is a lectin composed of four subunits, two of approximately 10,000 daltons and two of 16,000 daltons each. This 50,000 dalton glycoprotein appears to bind only O-glycosidically linked oligosaccharides, preferring the structure galactosyl (b-1,3) N-acetylgalactosamine. This structure (the so-called “T-antigen”) is the oligosaccharide to which peanut agglutinin binds. However, unlike PNA, Jacalin will bind this structure even in a mono- or disialylated form. This lectin has been used to purify human IgA, since no other human immunoglobulin class binds Jacalin (references available upon request). The specificity of this lectin also affords the opportunity to localize or isolate glycoproteins with O-glycosidically linked oligosaccharide side chains. Fluorescein labeled Jacalin is produced by using the highest quality fluorescein isothiocyanate, our affinity-purified lectin, and special conjugation procedures. Fluorescein labeled Jacalin has an appropriate number of fluorochromes bound which provide the maximum fluorescence and optimum staining characteristics for this particular lectin. This lectin is supplied essentially free of unconjugated fluorochromes and inactive lectin. Fluorescein labeled Jacalin has an excitation at 495 nm and an emission at about 515 nm. |