N-Acetylgalactosamine-terminated glycans (GalNAc-glycans)

N-Acetylgalactosamine (GalNAc)-terminated glycans are carbohydrate motifs found on the terminal ends of glycoproteins and glycoconjugates, serving as critical recognition markers in biological systems (Stockert, 1995, PMID: 7590387). Their primary physiological role involves the regulation of serum glycoprotein levels through high-affinity binding to the asialoglycoprotein receptor (ASGPR) located on hepatocytes, which triggers rapid internalization and lysosomal degradation (D'Souza & Devarajan, 2015, PMID: 25913390). This specific hepatocyte-targeting capability has been extensively harnessed in the development of RNA interference (RNAi) therapeutics, where synthetic trivalent GalNAc clusters are conjugated to siRNAs to ensure precise delivery to the liver (Nair et al., 2014, PMID: 24510543). Furthermore, in many human cancers, the aberrant expression of terminal GalNAc residues, known as the Tn antigen, occurs due to incomplete glycosylation, making these glycans important biomarkers and targets for immunotherapy (Ju et al., 2014, PMID: 24737483). The therapeutic utility of GalNAc-terminated glycans spans from serving as a delivery vehicle for metabolic disease treatments to acting as a tumor-specific antigen in oncology (Springer, 1984, PMID: 6385668).

Other names

Terminal N-acetylgalactosamineTn antigenGalNAc-terminated oligosaccharidesGalNAc-conjugated glycoconjugates

Binding to the asialoglycoprotein receptor (ASGPR) to facilitate hepatocyte-specific uptake via clathrin-mediated endocytosis (Nair et al., 2014, PMID: 24510543).