Solanum tuberosum lectin/agglutinin (STA/STL) is isolated from potato. This lectin is a glycoprotein that contains 50% carbohydrates and consists of two subunits with a molecular weight of 50 kDa. Each subunit of the lectin contains three regions. The N-terminal domain with several proline residues is not glycosylated. The next domain has high content of hydroxyproline (all substituted with L-arabinose) and has some serine residues substituted with galactose. The third domain is not glycosylated, has a high content of cysteine and carries the carbohydrate binding site.

STA has an isoelectric point greater than pH 9 and has a specificity towards (GlcNAc)2-4, and elutes with the sugar chitin hydrolysate. STA binds oligomers of N-acetylglucosamine and some bacterial cell wall oligosaccharides containing N-acetylglucosamine and N-acetylmuramic acid. N-acetyllactosamine is a relatively weak inhibitor of hemagglutination induced by this lectin. STA does not have a blood group specificity.