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Heterogeneity of human hepatic H-acetyl-beta-D-hexosaminidose. A activity toward natural glycosphingolipid substrates.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 1975 Feb 25; Vol. 250 (4), pp. 1328-32. - Publication Year :
- 1975
-
Abstract
- A crude soluble preparation of human hepatic N-acetyl-beta-D-hexosaminidase was examined for its activities toward three natural glycosphingolipid substrates after fractionation by the isoelectric focusing procedure. Profiles of activities toward N-acetylgalactosaminyl-galactosyl-glucosylceramide (asialo GM2-ganglioside) and N-acetylgalactosaminyl-galactosyl-galactosyl-glucosylceramide (globoside) were always identical with that of nonspecific N-acetyl-beta-D-hexosaminidase as determined with artificial substrates. The Component A of the enzyme had the activity peak at an isoelectric point of 5.0 to 5.1. In contrast, hydrolytic activities toward N-acetylgalactosaminyl-[N-acetylneuraminyl]galactosyl- glucosylceramide (GM2-ganglioside) were associated with only the most acidic subfraction of the hexosaminidase A component. The activity to hydrolyze GM2-ganglioside had its peak at an isoelectric point of 4.8 to 4.9. These findings might provide an explanation for the GM2-ganglioside accumulation in juvenile GM2-gangliosidosis (partial deficiency of hexosaminidase A) and in the so-called AB variant of GM2-gangliosidosis (apparently normal hexosaminidase A and B activity).
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 250
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 1112809