Fig.19. Schematic illustration of a non-radioactive glycosyl-transferase assay, using sialyltransferase as an example. The appropriate biotinylated neoglycoconjugate (a) is exposed to a solution with an unknown quantity of enzymatic activity and the activated sugar as substrate (b). After termination of the reaction the mixture transferred to a matrix containing immobilised streptavidin that will bind the biotin-containing neoglycoconjugate (c). Addition of a labelled lectin such as the commercially available and well-characterised agglutinin from Limax flavus, Maackia amurensis or Sambucus nigra or an antibody with suitable specificity for the expected product, and performance of a routine ELISA-type assay will enable the determination of the extent of product formation.