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Updated: Oct 7, 2026
A Mass Spectrometry-Based Approach to Identify Phosphoprotein Phosphatases and their Interactors
Published on: April 29, 2022
[Phosphatase from Proteus mirabilis]
Z Z Salikhova1, R B Sokolova, D V Iusupova
1Kazan State University, Kazan, 420008 Russia.
Abstract:
Cell-free preparations of Proteus mirabilis contained a phosphatase (EC 3.1.3.1), whose activity surpassed that of alkaline phosphatase from Escherichia coli. Phosphatase was also found in the culture liquid of P. mirabilis. The composition of proteins displaying enzyme activity was assayed by polyacrylamide gel electrophoresis. Enzyme synthesis was studied at various stages of bacterial growth. Biosynthesis of phosphatase in P. mirabilis (similarly to that in other bacteria) was shown to be induced under conditions of inorganic phosphate deficiency in the medium.
Insights
Proteus mirabilis produces a highly active phosphatase enzyme, exceeding that of E. coli. Its synthesis is induced by low inorganic phosphate levels, indicating a regulated metabolic response.
Area of Science:
- Microbiology
- Enzymology
- Biochemistry
Background:
- Proteus mirabilis possesses phosphatase activity.
- Alkaline phosphatase from Escherichia coli is a common benchmark.
- Extracellular enzyme activity in bacteria is significant.
Purpose of the Study:
- To characterize the phosphatase activity in Proteus mirabilis.
- To compare its activity with Escherichia coli alkaline phosphatase.
- To investigate the regulation of phosphatase biosynthesis.
Main Methods:
- Cell-free preparations and culture liquid analysis.
- Polyacrylamide gel electrophoresis for protein composition.
- Enzyme synthesis studies during bacterial growth phases.
Main Results:
- Proteus mirabilis phosphatase activity was higher than Escherichia coli alkaline phosphatase.
- Phosphatase was detected in both cell-free extracts and culture supernatant.
- Enzyme synthesis was induced by inorganic phosphate deficiency.
Conclusions:
- Proteus mirabilis harbors a potent extracellular phosphatase.
- Phosphate availability regulates the biosynthesis of this enzyme.
- The findings contribute to understanding bacterial enzyme regulation.
