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Membrane-associated alkaline phosphatase from Bacillus licheniformis that requires detergent for solubilization:
Abstract:
When membranes of Bacillus licheniformis MC14 were extracted exhaustively with 1 M magnesium, approximately 80% of the membrane-associated alkaline phosphatase (orthophosphoric-monoester phosphohydrolase [alkaline optimum], E.C. 3.1.3.1) was solubilized. The remaining activity could be extracted with a cationic detergent, hexadecylpyridinium chloride, without loss of enzymatic activity. The detergent-extractable alkaline phosphatase was immunoprecipitable with antibody to the salt-extractable alkaline phosphatase or the secreted alkaline phosphatase, had an approximate molecular weight of 60,000, and was localized 100% on the outer surface of the cytoplasmic membrane.
Insights
Researchers extracted alkaline phosphatase (orthophosphoric-monoester phosphohydrolase [alkaline optimum]) from Bacillus licheniformis membranes. Most was solubilized with magnesium, while the rest required a cationic detergent, revealing its surface localization.
Area of Science:
- Microbiology
- Enzymology
- Biochemistry
Background:
- Alkaline phosphatase is an important enzyme found in various organisms.
- Understanding enzyme localization and extraction is crucial for biochemical studies.
- Bacillus licheniformis is a bacterium with biotechnological relevance.
Purpose of the Study:
- To investigate the extraction and localization of alkaline phosphatase in Bacillus licheniformis MC14 membranes.
- To characterize the properties of the membrane-associated alkaline phosphatase.
Main Methods:
- Exhaustive extraction of Bacillus licheniformis MC14 membranes using 1 M magnesium.
- Extraction of remaining alkaline phosphatase activity with hexadecylpyridinium chloride.
- Immunoprecipitation assays using antibodies against salt- and secreted alkaline phosphatase.
- Determination of molecular weight and localization of the enzyme.
Main Results:
- Approximately 80% of membrane-associated alkaline phosphatase was solubilized by magnesium extraction.
- The remaining activity was extracted using hexadecylpyridinium chloride without loss of enzymatic function.
- Detergent-extracted alkaline phosphatase showed immunoprecipitation with specific antibodies and had a molecular weight of approximately 60,000.
- The enzyme was localized exclusively on the outer surface of the cytoplasmic membrane.
Conclusions:
- Bacillus licheniformis MC14 alkaline phosphatase can be effectively extracted using sequential magnesium and cationic detergent treatments.
- The enzyme exists in distinct pools within the membrane, with a significant portion accessible via salt extraction.
- The characterized alkaline phosphatase is a surface-localized enzyme, suggesting potential roles in extracellular functions.