HIGH SUBSTRATE-SPECIFICITY AND INDUCTION CHARACTERISTICS OF TRIMETHYLAMINE-N-OXIDE REDUCTASE OF ESCHERICHIA-COLI

Using a wide variety of N- and S-oxide compounds we have shown by kine tic analysis that only two N-oxides, trimethylamine-N-oxide and 4-meth ylmorpholine-N-oxide, can be considered good substrates for trimethyla mine-N-oxide (TMAO) reductase on the basis of their k(cat)/K-m ratio, This result demonstrates that TMAO reductase possesses a high substrat e specificity. induction of the torCAD operon using the same S- and N- oxide compounds was also analyzed. We demonstrate that there is no cor relation between the ability for a compound to be reduced by TMAO redu ctase and to induce TMAO reductase synthesis.