The galactan-degrading enzymes in the snail Biomphalaria glabrata
| Autor: | Hagen Bretting, O. Breitfeld, Günter Jacobs, S. Müller |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Enzyme complex
Glycoside Hydrolases Physiology Biology Polysaccharide Biochemistry Galactans Substrate Specificity chemistry.chemical_compound Hydrolysis Biomphalaria glabrata Animals Molecular Biology chemistry.chemical_classification Membranes Biomphalaria Temperature General Medicine Metabolism Galactan Hydrogen-Ion Concentration biology.organism_classification beta-Galactosidase Galactoside Molecular Weight Enzyme chemistry |
| Zdroj: | Comparative biochemistry and physiology. B, Comparative biochemistry. 99(3) |
| ISSN: | 0305-0491 |
| Popis: | 1. 1. Embryonic snails incorporate from the perivitelline fluid in which they are embedded a polysaccharide, called galactan, which is composed entirely of d -, or d - and l -galactose. In this investigation the p- nitrophenyl-β- d -galactoside degrading enzyme of Biomphalaria glabrata which was assumed to be involved in the degradation of the galactans was purified almost to homogeneity and its specificity was studied. 2. 2. It has a mol. wt of 135,000 and is composed of two identical subunits. 3. 3. It could be shown that p- nitrophenyl-β- d -fucoside was hydrolysed eight times faster, but native galactan was neither decomposed nor was it inhibitory for the hydrolysis of p-nitrophenyl-glycosides. 4. 4. Thus, it is most likely that this galactosidase is not involved in the galactan metabolism. 5. 5. However, a membrane-bound enzyme complex was revealed which was able to metabolize the native galactan of Biophalaria glabrata completely and which showed graded reactivity towards galactans of other species. 6. 6. Since no intermediate degradation products were found, it must be assumed that they were metabolized further in the mitochondria. |
| Databáze: | OpenAIRE |
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