Deuterium surface coil NMR study of the metabolism of D-methionine in the liver of the anesthetized rat

Journal Article · Tue Oct 04 04:00:00 EDT 1988 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00420a042· OSTI ID:6499534

London, R E; Gabel, S A

The hepatic metabolism of deuteriated D-methionine has been studied in the intact, anesthetized rat using 2H NMR spectroscopy. The rate of formation of the principal labeled metabolite, (methyl-2H3)sarcosine, from the D-(methyl-2H3)methionine precursor was found to be as rapid as the rate observed previously in NMR studies of the hepatic metabolism of L-methionine. Similarly, rates of clearance of labeled methionine from the liver, formation of N-trimethyl-labeled metabolites, and labeling of the HDO pool were all found to be similar to the rates observed in the L-methionine studies. In contrast, all of these metabolic transformations are strongly inhibited by pretreatment of the rats with sodium benzoate, an inhibitor of D-amino acid oxidase. In vivo 2H NMR studies of sodium benzoate treated rats given L-(methyl-2H3)-methionine exhibit a much more rapid formation of (methyl-2H3)sarcosine than rats given the D enantiomer, consistent with the expectation that the sodium benzoate does not interfere with either the formation of S-adenosylmethionine or the subsequent transmethylation of glycine. However, the rates of methionine clearance and formation of deuteriated water are markedly reduced in this study relative to rats receiving the labeled D- or L-methionine without sodium benzoate pretreatment. These results indicate that subsequent to the initial oxidative deamination of the labeled D-methionine, the reamination to give L-methionine is rapid compared with the further degradation of the alpha-keto acid. Thus, the results are consistent with a dominant contribution of the glycine/sarcosine shuttle to the metabolism of excess D- or L-methionine.

• Research Organization: National Institute of Environmental Health Sciences, Research Triangle Park, NC (USA)
• OSTI ID: 6499534
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 27:20; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
BODY
CARBOXYLIC ACIDS
DEUTERIUM
DIGESTIVE SYSTEM
DRUGS
GLANDS
HYDROGEN ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LIPOTROPIC FACTORS
LIVER
MAGNETIC RESONANCE
MAMMALS
METABOLISM
METABOLITES
METHIONINE
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
RATS
RESONANCE
RODENTS
SARCOSINE
SPECTRA
STABLE ISOTOPES
TRACER TECHNIQUES
VERTEBRATES