InterPro domain: IPR029019

This entry represents the N-terminal domain of the eukaryotic beta-hexosaminidases. There are 3 forms of beta-hexosaminidase: hexosaminidase A is a trimer, with one alpha, one beta-A and one beta-B chain; hexosaminidase B is a tetramer of two beta-A and two beta-B chains; and hexosaminidase S is a homodimer of alpha chains. The two beta chains are derived from the cleavage of a precursor.

In the brain and other tissues, beta-hexosaminidase A degrades GM2 gangliosides; specifically, the enzyme hydrolyses terminal non-reducing N-acetyl-D-hexosamine residues in N-acetyl-beta-D-hexosaminides. Mutations in the beta-hexosaminidase beta-chain lead to Sandhoff disease, a lysosomal storage disorder characterised by accumulation of GM2 ganglioside [ 1 ].

1. Molecular basis of an adult form of Sandhoff disease: substitution of glutamine for arginine at position 505 of the beta-chain of beta-hexosaminidase results in a labile enzyme. Biochim. Biophys. Acta 1182, 142-6