Aerobic degradation of choline by Proteus mirabilis: enzymatic requirements and pathway

Can J Microbiol. 1986 Sep;32(9):743-50. doi: 10.1139/m86-135.


Cleavage of choline to trimethylamine and acetaldehyde by extracts of Proteus mirabilis requires both particulate and soluble protein fractions, K+, and a bound divalent metal cation. The reaction shows a long lag period, abolished only by preincubation of the particulate fraction in the complete reaction system. The two-carbon fragment produced is acetaldehyde; choline cleavage appears to be tightly coupled to dismutation of the acetaldehyde to ethanol and acetate, as indicated by stimulation by NAD+, ADP, and Fe2+ and inhibition by reagents reacting with acetaldehyde. The system is thus similar to that previously described in anaerobes (Desulfovibrio, Clostridium). Attempts to demonstrate a cobamide coenzyme requirement (as in the similar ethanolamine ammonia-lyase reaction) were unsuccessful; the reaction was carried out by fractions devoid of vitamin B12 activity (not supporting growth of Lactobacillus leichmannii) and insensitive to light.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetaldehyde / analysis
  • Aerobiosis
  • Cell-Free System
  • Choline / analogs & derivatives
  • Choline / metabolism*
  • Kinetics
  • Methylamines / analysis
  • Proteus mirabilis / enzymology*


  • Methylamines
  • Acetaldehyde
  • trimethylamine
  • Choline