May transfer sialic acid through alpha-2,8-linkages to the alpha-2,3-linked and alpha-2,6-linked sialic acid of N-linked oligosaccharides of glycoproteins and may be involved in PSA (polysialic acid) expression.
Subcellular locations: Golgi apparatus membrane
Highly expressed in fetal brain, kidney and heart and to a much lesser extent in adult heart and thymus.