α-D-Galactopyranosylphenyl isothiocyanate is a chemically activated form of galactose that has been used to prepare various neoglycoproteins, which consist of a glycosylated serum albumin substituted with either fluorescein or methotrexate.[1] Neoglycoproteins are used to identify the presence and sugar specificity of membrane lectins on the cell surface of mouse L1210 leukemia cells and to study membrane lectin-mediated endocytosis.

References
[1]. Monsigny, M., Roche, A.C., and Midoux, P. Uptake of neoglycoproteins via membrane lectin(s) of L1210 cells evidenced by quantitative flow cytofluorometry and drug targeting. Biol.Cell 51(2), 187-196 (1984).