3-Azi-1-methoxybutyl beta-D-galactopyranoside, a photoaffinity label for monoclonal antigalactan antibodies of the VH GAL 39.1/55.1 gene-family.
3-Azi-1-methoxybutyl beta-D-galactopyranoside, prepared from 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl bromide in four steps, had an affinity constant for antigalactans IgA (Fab') J539 and X24 of 1550 and 1730 M-1, respectively. 3-Azi-1-methoxybutyl beta-D-(4-3H)galactopyranoside, when photolysed in the presence of IgA X24, specifically labelled the galactan-binding area of the immunoglobulin.