Beta 1,4-galactosyltransferase (beta 4GalT)-IV is specific for GlcNAc 6-O-sulfate. Beta 4GalT-IV acts on keratan sulfate-related glycans and a precursor glycan of 6-sulfosialyl-Lewis X.
The Galbeta1-->4(SO(3)(-)-->6)GlcNAc moiety is present in various N-linked and O-linked glycans including kera