A beta-galactosidase isoenzyme from Turbo cornutus with substrate specificity toward GM1-ganglioside and glycoproteins
| Autor: | Albert J. Owen, Kwok-Kam Yeung, Joel A. Dain |
|---|---|
| Rok vydání: | 1983 |
| Předmět: |
Physiology
Stereochemistry Size-exclusion chromatography G(M1) Ganglioside Biochemistry Substrate Specificity chemistry.chemical_compound Lactosylceramide Column chromatography Sodium citrate Animals music Molecular Biology Turbo cornutus Glycoproteins Chromatography music.instrument Molecular mass biology General Medicine biology.organism_classification beta-Galactosidase Fetuin Galactosidases Isoenzymes Molecular Weight Kinetics chemistry Mollusca Galactose |
| Zdroj: | Comparative biochemistry and physiology. B, Comparative biochemistry. 76(3) |
| ISSN: | 0305-0491 |
| Popis: | 1. 1. β-Galactosidase from T. cornutus was resolved into two activity peaks by gel filtration column chromatography. 2. 2. The pH optima of the two peaks designated P1 and P2, were 5.5 and 3.0, respectively, when p- nitrophenyl -β- d -galactopyranoside was used as the substrate. 3. 3. The molecular weights of P1 and P2 were 700,000 ± 70,000 and 78,000 ± 7800, respectively, when estimated by gel filtration chromatography. 4. 4. The activities of both forms of the enzymes are stimulated by anions such as Cl−, Br− and NO3−. While the activity of P1 was stimulated by low anion concentrations, P2 requires 700 times higher anion concentration for similar enhancement of activity. 5. 5. P1, the high molecular weight form hydrolyzes mainly galactose from small molecular weight β-galactosides, such as p- nitrophenyl -β- d -galactopyranoside , 4- methylumbelliferyl -β- d -galactopyranoside , lactose, lactosylceramide and 3-O-β- d -galactopyranosyl- d -arabinose , whereas P2, the low molecular weight form cleaves, in addition, all the β-galactoside tested, including 2-hexadecanoylamino-4-nitrophenyl-β- d -galactopyranoside, GM1-ganglioside, asialo-GM1-ganglioside, asialo fetuin, α1-acid glycoproteins and the tryptic peptides of the glycoproteins. 6. 6. The optimal conditions for the hydrolysis of the terminal galactose from GM1-ganglioside which does not occur in gastropods, such as T. cornutus, was found to require 40 mM NaCl and 1 mM sodium taurodeoxycholate at pH 3.0 in 50 mM sodium citrate buffer, conditions similar to those by mammalian β-galactosidase. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|