Tay-Sachs disease: one-step assay of beta-N-acetylhexosaminidase in serum with a sulphated chromogenic substrate.
A sulphated chromogenic compound, p-nitrophenyl-6-sulpho-2-acetamido-2-deoxy-beta-D-glucopyranoside, which can be hydrolysed enzymatically to p-nitrophenol and the sulphated amino sugar, was used as a substrate for the determination of activity of beta-N-acetylhexosaminidase isoenzymes in human serum. The sera of six Tay-Sachs patients lacking isoenzyme A and heat-inactivated control serum exhibited 6% of the mean normal enzyme activity of 1.32 U/l (1-s range = 1.07-1.57 U/l). In 10 obligate carriers of the Tay-Sachs gene the enzyme activity was 52% (1-s range = 45-60%) of the mean normal value. Therefore, by using the sulphated chromogenic substrate Tay-Sachs disease can be diagnosed enzymatically in a simple one-step procedure, but the 2-s activity ranges of heterozygotes and normals overlap. The assay is not absolutely specific for isoenzyme A of beta-N-acetylhexosaminidase, because the substrate can be hydrolysed to a certain extent by beta-N-acetylhexosaminidase I.
D000117:Acetylglucosamine / Q000031:analogs & derivatives / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002863:Chromogenic Compounds / Q000378:metabolism; D006579:Heterozygote; D006596:Hexosaminidases / Q000097:blood*; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000097:blood*; D008875:Middle Aged; D013661:Tay-Sachs Disease / Q000097:blood*; D001619:beta-N-Acetylhexosaminidases
D002863:Chromogenic Compounds; D007527:Isoenzymes; C038069:4-nitrophenyl-6-sulfo-2-acetamido-2-deoxyglucose; D006596:Hexosaminidases; D001619:beta-N-Acetylhexosaminidases; D000117:Acetylglucosamine