Galacto-N-biose, a component of the galacto-N-biose/lacto-N-biose metabolic pathway, is used as a substrate to identify, differentiate and characterize enzymes such as N-acetylglucosaminyltransferase(s), fucosyl- and sialyltransferase(s), galactosidase(s) and galacto-N-biose/lacto-N-biose I phosphorylase(s) (GLNBP). Galacto-N-biose is used in lectin inhibition studies.