This lectin consists of two subunits of 60 kDa which can be dissociated by reducing agents into closely related chains between 27 kDa and 33 kDa. One of the chains appears to be common to the “B” chain of another castor bean lectin, ricin, while the other chain is unique to RCA I. The B chain binds to galactose or N-acetylgalactosamine residues of membrane glycoconjugates.
Fluorescein labeled Ricinus communis agglutinin I has an appropriate number of fluorochromes bound to provide the optimum staining characteristics for this lectin. This conjugate is supplied essentially free of unconjugated fluorochromes. The excitation maximum is at 495 nm and the emission maximum is at 515 nm.