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Pseudomonas putida A ATCC 12633 oxidizes trimethylamine aerobically via two different pathways
Andrés S Liffourrena1, Mario A Salvano, Gloria I Lucchesi
1Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fisico-Químicas y Naturales, Universidad Nacional de Río Cuarto, CPX5804BYA, Río Cuarto, Córdoba, Argentina.
Archives of Microbiology
|May 4, 2010
Summary
Pseudomonas putida A ATCC 12633 metabolizes trimethylamine aerobically using two key enzymes. Trimethylamine accumulation, which hinders bacterial growth, may result from the enzymes
Area of Science:
- Microbial metabolism
- Enzymology
- Bacterial physiology
Background:
- Pseudomonas putida A ATCC 12633 utilizes trimethylamine (TMA) as a nitrogen source.
- TMA accumulation inhibits bacterial growth when grown on TMA or tetradecyltrimethylammonium bromide (TTAB).
- Aluminum chloride (AlCl3) addition mitigates growth inhibition.
Purpose of the Study:
- To investigate the aerobic metabolism of trimethylamine in Pseudomonas putida A ATCC 12633.
- To identify the enzymes involved in TMA oxidation and their kinetic properties.
- To elucidate the reasons for TMA accumulation and growth inhibition.
Main Methods:
- Cultivation of Pseudomonas putida A ATCC 12633 on TMA or TTAB.
- Preparation of cell-free extracts.
- Enzyme activity assays for trimethylamine monooxygenase and trimethylamine dehydrogenase.
- Kinetic analysis (Km, catalytic efficiency) and inhibition studies.
Main Results:
- Two distinct enzymatic pathways initiate aerobic TMA oxidation: trimethylamine monooxygenase (TMAO production) and trimethylamine dehydrogenase (dimethylamine production).
- Trimethylamine monooxygenase (Km = 0.7 mM) and trimethylamine dehydrogenase (Km = 4.0 mM) exhibit similar catalytic efficiencies.
- Trimethylamine dehydrogenase activity is inhibited by TMA at concentrations above 1 mM.
Conclusions:
- Pseudomonas putida A ATCC 12633 employs two enzymes for the initial aerobic oxidation of trimethylamine.
- The observed TMA accumulation and subsequent growth inhibition are likely attributed to the low catalytic efficiency and substrate inhibition of these key enzymes.
- AlCl3 may counteract growth inhibition by influencing TMA uptake or metabolic pathways.
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