Carnitine biosynthesis in hepatic peroxisomes. Demonstration of gamma-butyrobetaine hydroxylase activity

Eur J Biochem. 1992 Feb 1;203(3):599-605. doi: 10.1111/j.1432-1033.1992.tb16589.x.


We have investigated whether hepatic peroxisomes are capable of synthesizing carnitine. When purified peroxisomes were incubated with gamma-butyrobetaine, a precursor of carnitine, formation of carnitine was observed. These results indicate that peroxisomes contain gamma-butyrobetaine hydroxylase, the enzyme which catalyzes the final step in the biosynthesis of carnitine. This enzyme was previously believed to be present only in the cytosol. gamma-Butyrobetaine hydroxylase activity in peroxisomes was not due to cytosolic contamination as evaluated by marker enzyme analysis. When proliferation of peroxisomes was induced by clofibrate treatment, gamma-butyrobetaine hydroxylase/mass liver increased by 7.6-fold and the specific activity by 2.5-fold. We conclude that hepatic peroxisomes synthesize carnitine and this synthesis becomes substantial under conditions of peroxisomal proliferation.

MeSH terms

  • Animals
  • Carnitine / biosynthesis*
  • Cell Fractionation
  • Clofibrate / pharmacology
  • Fatty Acids / metabolism
  • Hydrolysis
  • Liver / cytology
  • Liver / drug effects
  • Liver / enzymology*
  • Male
  • Microbodies / drug effects
  • Microbodies / metabolism*
  • Mixed Function Oxygenases / metabolism*
  • Oxidation-Reduction
  • Rats
  • Rats, Inbred Strains
  • gamma-Butyrobetaine Dioxygenase


  • Fatty Acids
  • Mixed Function Oxygenases
  • gamma-Butyrobetaine Dioxygenase
  • Clofibrate
  • Carnitine