title: Specific determination of N-acetyl-beta-D-hexosaminidase isozymes A and B by radioimmunoassay and radial immunodiffusion.
abstract: The two major isozymes of N-acetylhexosaminidase, namely hexosaminidases A and B were quantitatively determined in tissues and biological fluids of both normal individuals and Tay-Sachs patients. The determination was carried out by two sensitive immunoassays:radial immunodiffusion, using chromogenic substrate, and radioimmunoassay, which were developed in this study. For this purpose [corrected] we used either a cross-reactive antiserum which reacts to a similar extent with both isozymes, or an antiserum reacting exclusively with hexosaminidase A (obtained by selective immunoadsorption). This enabled the quantitisation of the two isozymes separately, or in the presence of each other, in purified enzyme preparations or in tissue homogenates, affording a direct positive determination of hexosaminidase A. The results demonstrated that normal tissues contain the two isozymes in comparable amounts, whereas tissues of Tay-Sachs patients lack hexosaminidase A or any material which carries the A-specific antigenic determinants. The possible applications of these assays and their potential use in diagnosis are discussed.
mesh_terms: D000118:Acetylglucosaminidase / Q000032:analysis* / Q000276:immunology; D001666:Binding Sites, Antibody; D003429:Cross Reactions; D005260:Female; D005333:Fetus; D006596:Hexosaminidases / Q000032:analysis*; D006801:Humans; D005779:Immunodiffusion; D007527:Isoenzymes / Q000032:analysis* / Q000276:immunology; D008064:Lipidoses / Q000201:enzymology; D008099:Liver / Q000196:embryology / Q000201:enzymology; D011247:Pregnancy; D011863:Radioimmunoassay
chemical_list: D007527:Isoenzymes; D006596:Hexosaminidases; D000118:Acetylglucosaminidase