M.S. (Master of Science)
Department of Biological Sciences
Escherichia coli K-12, when grown anaerobically on glycerol, can utilize dimethyl sulfoxide (DMSO) and trimethylamine N-oxide (TMAO) as terminal electron acceptors. TMAO reductase and DMSO reductase are the two enzymes involved in the reduction of these compounds. The overlapping substrate specificities of these enzymes have led to confusion as to their in vivo role. We have isolated transposon TnlO insertion and deletion mutants in the dins operon. These mutants failed to grow on glycerol/DMSO but their growth on glycerol/TMAO was unaffected. These mutants also retained the ability to utilize other N-oxides such as nicotinamide N-oxide (NAMO), nicotinic acid N-oxide (NAO)and adenine N-oxide (ANO) as terminal electron acceptors. To further clarify these results, we heated cell-free extracts from wild type cells of E. coli at 70°C for 15 min resulting in selective inactivation of DMSO reductase activity with TMAO reductase activity unaffected. These results indicate that TMAO reductase, and not DMSO reductase, is the major enzyme involved in TMAO reduction.
Daruwala, Rushad C., "Reduction of trimethylamine N-oxide is not dependent on dimethlsulfoxide reductase activity in escherichia coli" (1992). Graduate Research Theses & Dissertations. 4667.
vi, 23 pages
Northern Illinois University
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