Ado-B12-dependent
              diol dehydratase
                 (PduCDE)






propanol dehydrogenase
       (PduQ)




                    OH

         propanol


     OH



1,2-propanediol





propionaldehyde


NAD


  ph trans


diol dehydratase 4   Ado-B12 reactivation factor
    (PduGH)         adenosyltransferase (PduO)




          CoA-dependent
   propionaldehyde dehydrogenase
             (PduP)



                   S-CoA


      propionyl-CoA osphoacylase?   V


    propionyl-phosphate


Figure 1-5. Putative pathway of aerobic PD degradation in S. enterica. As described in
           the text, conversion of propionaldehyde to propanol provides a sink for
           electrons generated from propionyl-CoA production and ATP is generated from the conversion of propionate-phosphate to propionate. Propionate is
           thought to enter the TCA cycle via the methyl-citrate pathway (Tsang et al.
           1998). The S. enterica proteins that encode the enzymes are listed next to
           each reaction.


X-B12