β-N-acetylhexosaminidase

β-N-ac·e·tyl·hex·os·amin·i·dase (as″ə-təl-) (as″ə-tēl″hek-sōs″ə-minґĭ-dās) [EC 3.2.1.52] a lysosomal enzyme of the hydrolase class that catalyzes the cleavage of N-acetylhexosamine residues from gangliosides or other glycosides; it is necessary for the degradation of keratan sulfate and also ganglioside GM₂ and related compounds. The enzyme comprises two polypeptide chains, α and β, which are arranged into three isozymes: A (αβ), B (ββ), and S (αα). Lack of isozyme A activity, due to a defect in the α chain, causes Tay-Sachs disease; lack of isozymes A and B, due to a defect in the β chain, causes Sandhoff disease. The enzyme is usually called hexosaminidase.