N-Acetylgalactosamine (GalNAc)

N-Acetylgalactosamine (GalNAc), is an amino sugar derivative of galactose. In humans it is the terminal carbohydrate forming the antigen of blood group A. It is typically the first monosaccharide that connects serine or threonine in particular forms of protein O-glycosylation. N-Acetylgalactosamine is necessary for intercellular communication, and is concentrated in sensory nerve structures of both humans and animals. It was demonstrated recently that there is a system of general protein glycosylation in the human enteropathogen Campylobacter jejuni. Binding of lectin SBA was disrupted by mutagenesis of genes within the previously identified protein glycosylation locus. A 28kDa band was identified as PEB3, a previously characterized immunogenic cell surface protein.