Sambucus nigra lectin (SNL) is isolated from elderberry bark and binds preferentially to sialic acid attached to terminal galactose in a-2,6 and to a lesser degree, a-2,3 linkage. Also called SNA (Sambucus nigra agglutinin) and EBL (elderberry lectin), SNL can inhibit cell-free protein synthesis. Binding is also inhibited to some extent by lactose or galactose. This lectin does not appear to bind sialic acid linked to N-acetylgalactosamine. SNA has been reported to inhibit cell-free protein synthesis. This fluorescein-labeled SNL features a ratio of fluorophores to lectin protein that provides optimal staining (excitation 495 nm, emission 515 nm). Supplied as a solution essentially free of unconjugated fluorophores, it is preserved with sodium azide. The recommended inhibiting/eluting sugar is 500 mM lactose in buffered saline followed by 500 mM lactose in acetic acid.