Yeast, plants, worms, and flies use a methyltransferase to metabolize age-damaged (R,S)-AdoMet, but what do mammals do?

Rejuvenation Res. Apr-Jun 2010;13(2-3):362-4. doi: 10.1089/rej.2009.0956.

Abstract

The biological methyl donor S-adenosyl-L-methionine [(S,S)-AdoMet] can spontaneously break down under physiological conditions to form the inactive diastereomer (R,S)-AdoMet, which may interfere with cell function. Although several lower organisms metabolize (R,S)-AdoMet via homocysteine methyltransferases, it is unclear how mammals deal with it. In this paper, we show that the mouse liver extracts, containing the BHMT-2 homocysteine methyltransferase candidate for a similar activity, recognizes (S,S)-AdoMet but not (R,S)-AdoMet. We find no evidence for the enzymatic breakdown of (R,S)-AdoMet in these extracts. Thus, mammals may metabolize (R,S)-AdoMet using a different strategy than other organisms.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / metabolism*
  • Animals
  • Betaine-Homocysteine S-Methyltransferase / metabolism
  • Betaine-Homocysteine S-Methyltransferase / physiology
  • Catalysis
  • Diptera / genetics
  • Diptera / metabolism
  • Helminths / genetics
  • Helminths / metabolism
  • Homocysteine S-Methyltransferase / metabolism*
  • Homocysteine S-Methyltransferase / physiology
  • Humans
  • Liver / enzymology
  • Liver / metabolism
  • Mammals / genetics
  • Mammals / metabolism*
  • Mice
  • Molecular Conformation
  • Oxidative Stress
  • Plants / genetics
  • Plants / metabolism
  • S-Adenosylmethionine / chemistry
  • S-Adenosylmethionine / metabolism*
  • Saccharomyces cerevisiae Proteins / metabolism
  • Saccharomyces cerevisiae Proteins / physiology
  • Substrate Specificity
  • Yeasts / genetics
  • Yeasts / metabolism

Substances

  • Bhmt2 protein, mouse
  • Saccharomyces cerevisiae Proteins
  • S-Adenosylmethionine
  • Homocysteine S-Methyltransferase
  • MHT1 protein, S cerevisiae
  • SAM4 protein, S cerevisiae
  • Betaine-Homocysteine S-Methyltransferase