Exostosin 1/2 Heterodimer Products

Description

Exostosin (EXT) family of glycosyltransferases are involved in heparan sulfate (HS) and heparin biosynthesis (1). Mutations of these enzymes are the causes of hereditary multiple exostoses, which are characterized by formation of numerous cartilage-capped, benign bone tumors (osteocartilaginous exostoses or osteochondromas) that are often accompanied by skeletal deformities and short stature (2). In a small percentage of cases exostoses have exhibited malignant transformation resulting in an osteosarcoma or chondrosarcoma (3). Five members of this family have been cloned to date: EXT1, EXT2, EXTL1, EXTL2, and EXTL3. EXT1 and EXT2 are bifunctional enzymes with both beta -1,4-glucuronyltransferase and alpha -1,4-N-acetylglucosaminyltransferase activities that elongate HS chains with alternating beta -1,4-GlcA and alpha -1,4-GlcNAc residues on the non-reducing end (4). EXT1 is an active enzyme, but the hetero-dimer of EXT1 and EXT2 has increased stability and activity (1). The enzyme activity is measured using a phosphatase-coupled assay (5).

Bioinformatics

Uniprot	Q16394 (EXT1) & Q93063 (EXT2)
Alternate Names	Exostosin 1/2 Heterodimer EXT1/EXT2 Heterodimer