The Catabolism of Tay-Sachs Ganglioside in Rat Brain Lysosomes

The Catabolism of Tay-Sachs Ganglioside in Rat Brain Lysosomes

The metabolism of Tay-Sachs ganglioside, Cer-Glc-Gal-(NeuAc)-GalNAc (Gm2) was investigated by using Gm2 specifically labeled with 3H in the NeuAc moiety or with 14C in GalNAc. There are two possible pathways for the catabolism of Gm2 in brain, initiated via Gm2-sialidase or Gm2hexosaminidase. The pr...

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Veröffentlicht in:The Journal of biological chemistry 1972-12, Vol.247 (23), p.7570-7575
Hauptverfasser: Tallman, John F., Brady, Roscoe O.
Format: Artikel
Sprache:eng
Schlagworte:
Acetates - metabolism
Animals
Brain - cytology
Brain - metabolism
Carbon Isotopes
Chromatography, Thin Layer
Cytosol - enzymology
Gangliosides - biosynthesis
Gangliosides - metabolism
Hexosamines - metabolism
Hexosaminidases - metabolism
Hydrogen-Ion Concentration
Kinetics
Lipid Metabolism
Lipidoses - etiology
Lipidoses - metabolism
Lysosomes - enzymology
Lysosomes - metabolism
Male
Mannose - metabolism
Neuraminidase - metabolism
Rats
Subcellular Fractions - enzymology
Surface-Active Agents - pharmacology
Tritium
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Zusammenfassung:The metabolism of Tay-Sachs ganglioside, Cer-Glc-Gal-(NeuAc)-GalNAc (Gm2) was investigated by using Gm2 specifically labeled with 3H in the NeuAc moiety or with 14C in GalNAc. There are two possible pathways for the catabolism of Gm2 in brain, initiated via Gm2-sialidase or Gm2hexosaminidase. The products of the sialidase reaction were identified and are Cer-Glc-Gal-GalNAc and NeuAc; the hexosaminidase yields Cer-Glc-Gal-NeuAc and GalNAc. The pH optimum, apparent Km, and Vmax of these enzymes were determined. These findings both support the presence of two alternate pathways in mammalian brain for the catabolism of Tay-Sachs ganglioside and form a starting point for the eventual clarification of the molecular pathogenesis of Tay-Sachs disease.
ISSN:0021-9258
1083-351X
DOI:10.1016/S0021-9258(19)44563-8