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The putative coenzyme B12-dependent methylmalonyl-CoA mutase from potatoes is a phosphatase

Csaba Paizs1, Tanja Diemer, János Rétey

  • 1Department of Biochemistry and Biochemical Engineering, Babeş-Bolyai University, 400028-Arany János 11, Cluj-Napoca (Kolozsvár), Romania.

Bioorganic Chemistry
|August 1, 2008
PubMed

Insights

Potato enzymes do not require coenzyme B12. Research shows the methylmalonyl-CoA mutase enzyme actually converts methylmalonyl-3'-dephospho-CoA, a reaction not dependent on coenzyme B12 or S-adenosylmethionine.

Area of Science:

  • Biochemistry
  • Plant Science
  • Enzymology

Background:

  • Previous studies suggested potatoes possess a coenzyme B12-dependent methylmalonyl-CoA mutase.
  • This enzyme is crucial in various metabolic pathways.

Purpose of the Study:

  • To re-examine the reported presence and function of methylmalonyl-CoA mutase in potatoes.
  • To clarify the enzymatic activity and cofactor requirements in potato metabolism.

Main Methods:

  • Purification of the enzyme converting methylmalonyl-CoA to electrophoretic homogeneity.
  • Analysis of the reaction product using advanced spectroscopic techniques: 1H NMR, 31P NMR, and mass spectrometry.

Main Results:

  • The purified enzyme was identified as a phosphatase, not a mutase.
  • The reaction product was confirmed to be methylmalonyl-3"-dephospho-CoA.
  • The enzyme's activity was found to be independent of coenzyme B12 and S-adenosylmethionine.

Conclusions:

  • Potatoes do not possess a coenzyme B12-dependent methylmalonyl-CoA mutase.
  • The identified enzyme is a phosphatase acting on methylmalonyl-CoA, with distinct cofactor requirements.
  • This finding revises the understanding of specific metabolic pathways in plants.

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