Coenzyme B12-dependent eliminases: Diol and glycerol dehydratases and ethanolamine ammonia-lyase

Tetsuo Toraya, Takamasa Tobimatsu, Koichi Mori, Mamoru Yamanishi, Naoki Shibata

Research output: Chapter in Book/Report/Conference proceedingChapter

1 Citation (Scopus)


Adenosylcobalamin (AdoCbl) or coenzyme B12-dependent enzymes catalyze intramolecular group-transfer reactions and ribonucleotide reduction in a wide variety of organisms from bacteria to animals. They use a super-reactive primary-carbon radical formed by the homolysis of the coenzyme's Co-C bond for catalysis and thus belong to the larger class of “radical enzymes.” For understanding the general mechanisms of radical enzymes, it is of great importance to establish the general mechanism of AdoCbl-dependent catalysis using enzymes that catalyze the simplest reactions—such as diol dehydratase, glycerol dehydratase and ethanolamine ammonia-lyase. These enzymes are often called “eliminases.” We have studied AdoCbl and eliminases for more than a half century. Progress has always been driven by the development of new experimental methodologies. In this chapter, we describe our investigations on these enzymes, including their metabolic roles, gene cloning, preparation, characterization, activity assays, and mechanistic studies, that have been conducted using a wide range of biochemical and structural methodologies we have developed.

Original languageEnglish
Title of host publicationCoenzyme B Enzymes Part A
EditorsE. Neil G. Marsh
PublisherAcademic Press Inc.
Number of pages62
ISBN (Print)9780323915915
Publication statusPublished - Jan 2022

Publication series

NameMethods in Enzymology
ISSN (Print)0076-6879
ISSN (Electronic)1557-7988


  • Adenosylcobalamin
  • Coenzyme B12
  • Diol dehydratase
  • Eliminase
  • Enzyme mechanism
  • Ethanolamine ammonia-lyase
  • Glycerol dehydratase
  • Radical enzyme
  • Vitamin B12
  • X-ray structure

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology


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