Maackia Amurensis Lectin I (MAL I), Biotinylated, 2 mg, binds gal (beta-1,4) glcNAc but tolerates substitution of N-acetyllactosamine with sialic acid at the 3 position of galactose. However, MAL I does not appear to bind this structure when substitution with sialic acid is on the 6 position of galactose. Biotinylated Maackia amurensis lectin has an appropriate number of biotins bound to provide the optimum staining characteristics for this lectin. This conjugate is supplied essentially free of unconjugated biotins and is preserved with sodium azide.