Sambucus nigra agglutinin (SNA) is a lectin isolated from elderberry bark that binds preferentially to sialic acid attached to terminal galactose in α-2,6 and to a lesser degree, α-2,3 linkage. 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 Cy5-labeled SNA features a ratio of fluorochrome to lectin that provides optimal staining (excitation 649 nm, emission 670 nm, color far red) and is supplied essentially free of unconjugated fluorochrome.