The Catabolism of Tay-Sachs Ganglioside in Rat Brain Lysosomes
1972; Elsevier BV; Volume: 247; Issue: 23 Linguagem: Inglês
10.1016/s0021-9258(19)44563-8
ISSN1083-351X
AutoresJohn F. Tallman, Roscoe O. Brady,
Tópico(s)Carbohydrate Chemistry and Synthesis
ResumoAbstract 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.
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