This lectin is a family of tetrameric glycoproteins consisting of combinations of A and B subunits similar in structure to PHA and GSL I. The dominant isolectins in our preparations appear to be B subunit-rich. VVL recognizes preferentially alpha- or beta-linked terminal N-acetylgalactosamine, especially a single alpha N-acetylgalactosamine residue linked to serine or threonine in a polypeptide (the “Tn antigen”). Evidence suggests that this lectin also may require specific amino acid sequences at the receptor site of glycosylation. The disaccharide galactosyl (a-1,3) N-acetylgalactosamine is also a potent inhibitor of this lectin.Fluorescein labeled Vicia Villosa Lectin is produced by using the highest quality fluorescein isothiocyanate, our affinity-purified lectin, and special conjugation procedures. Fluorescein labeled Vicia Villosa Lectin 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 Vicia Villosa Lectin has an excitation at 495 nm and an emission at about 515 nm.Accompanying each fluorescent lectin is an analysis data sheet summarizing the results of our quality control tests and providing pertinent information on the product. All of these reagents are supplied as solutions perserved with sodium azide.