Purification and properties ofl-serine dehydratase fromLactobacillus fermentum ATCC 14931
| Autor: | Guillermo Oliver, Ana M. Strasser de Saad, Aida Pesce de Ruiz Holgado, Marta E. Farías |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
chemistry.chemical_classification
Chromatography biology Lactobacillus fermentum Size-exclusion chromatography Substrate (chemistry) General Medicine biology.organism_classification Applied Microbiology and Biotechnology Microbiology Cofactor chemistry.chemical_compound Enzyme Serine dehydratase chemistry Dehydratase biology.protein Sodium dodecyl sulfate |
| Zdroj: | Current Microbiology. 22:205-211 |
| ISSN: | 1432-0991 0343-8651 |
| DOI: | 10.1007/bf02092310 |
| Popis: | l-Serine dehydratase fromLactobacillus fermentum was purified 100-fold. It was stabilized by the presence of 1 mMl-cysteine in 50 mM phosphate buffer. Mr=150,000 was determined by gel filtration. The enzyme consists of four apparently identical subunits (Mr=40,000) that were observed after treatment with sodium dodecyl sulfate. The apparent Km forl-serine was 65 mM. Fe++ was required for the enzymatic activity, and the apparent Km value for this reaction was 0.55 mM. Maximum enzymatic activity was observed at 45°C and pH 8.0 in 50 mM phosphate buffer. At pH values different from the optimum, a positive cooperativity between substrate molecules was observed. The activation energy of the reaction was 11,400 and 22,800 cal × mol−1 for temperature values more than and less than 35°C respectively. The purified enzyme showed a maximum absorption between 400 and 420 nm, indicating the presence of pyridoxal-5′-phosphate (PLP) as a prosthetic group. The PLP concentration was 0.027 µmoles per milligram of protein. The data suggest that there is 1 mol of PLP for each protein subunit. |
| Databáze: | OpenAIRE |
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