Reexamination of the 1H NMR assignments and solution conformations of l-carnitine and O-acetyl-l-carnitine using C-2 stereospecifically labeled monodeuterated isomers

Curtis F. Brewer, Hermann Seim, Sasha Englard

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3 Citations (Scopus)

Abstract

The two C-2 monodeuterated isomers of l-carnitine were synthesized by enzymatic hydration of crotonobetaine in D2O and by enzymatic proton exchange of l-[2-2H2] carnitine in H2O. These reactions, catalyzed by an induced Escherichia coli carnitine hydrolyase proceed stereospecifically. The two isomers of l-[2-2H]carnitine were examined by 1H NMR at 500 MHz, which allowed us to independently monitor the pD dependence and coupling constants of the H-2 protons. The results obtained indicate that there is little effect of the carboxyl charge on the conformational state(s) of l-carnitine about the C-2/C-3 bond. The NMR data obtained in this study do not support previous solution studies of the pH-dependent conformational changes for dl-carnitine nor the proposed conformation of O-acetyl-dl-carnitine in the crystalline state.

Original languageEnglish (US)
Pages (from-to)495-499
Number of pages5
JournalArchives of Biochemistry and Biophysics
Volume276
Issue number2
DOIs
StatePublished - Feb 1 1990

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Acetylcarnitine
Carnitine
Isomers
Conformations
Nuclear magnetic resonance
Protons
Proton Magnetic Resonance Spectroscopy
Hydration
Escherichia coli
Crystalline materials

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

Cite this

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title = "Reexamination of the 1H NMR assignments and solution conformations of l-carnitine and O-acetyl-l-carnitine using C-2 stereospecifically labeled monodeuterated isomers",
abstract = "The two C-2 monodeuterated isomers of l-carnitine were synthesized by enzymatic hydration of crotonobetaine in D2O and by enzymatic proton exchange of l-[2-2H2] carnitine in H2O. These reactions, catalyzed by an induced Escherichia coli carnitine hydrolyase proceed stereospecifically. The two isomers of l-[2-2H]carnitine were examined by 1H NMR at 500 MHz, which allowed us to independently monitor the pD dependence and coupling constants of the H-2 protons. The results obtained indicate that there is little effect of the carboxyl charge on the conformational state(s) of l-carnitine about the C-2/C-3 bond. The NMR data obtained in this study do not support previous solution studies of the pH-dependent conformational changes for dl-carnitine nor the proposed conformation of O-acetyl-dl-carnitine in the crystalline state.",
author = "Brewer, {Curtis F.} and Hermann Seim and Sasha Englard",
year = "1990",
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day = "1",
doi = "10.1016/0003-9861(90)90750-S",
language = "English (US)",
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pages = "495--499",
journal = "Archives of Biochemistry and Biophysics",
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publisher = "Academic Press Inc.",
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TY - JOUR

T1 - Reexamination of the 1H NMR assignments and solution conformations of l-carnitine and O-acetyl-l-carnitine using C-2 stereospecifically labeled monodeuterated isomers

AU - Brewer, Curtis F.

AU - Seim, Hermann

AU - Englard, Sasha

PY - 1990/2/1

Y1 - 1990/2/1

N2 - The two C-2 monodeuterated isomers of l-carnitine were synthesized by enzymatic hydration of crotonobetaine in D2O and by enzymatic proton exchange of l-[2-2H2] carnitine in H2O. These reactions, catalyzed by an induced Escherichia coli carnitine hydrolyase proceed stereospecifically. The two isomers of l-[2-2H]carnitine were examined by 1H NMR at 500 MHz, which allowed us to independently monitor the pD dependence and coupling constants of the H-2 protons. The results obtained indicate that there is little effect of the carboxyl charge on the conformational state(s) of l-carnitine about the C-2/C-3 bond. The NMR data obtained in this study do not support previous solution studies of the pH-dependent conformational changes for dl-carnitine nor the proposed conformation of O-acetyl-dl-carnitine in the crystalline state.

AB - The two C-2 monodeuterated isomers of l-carnitine were synthesized by enzymatic hydration of crotonobetaine in D2O and by enzymatic proton exchange of l-[2-2H2] carnitine in H2O. These reactions, catalyzed by an induced Escherichia coli carnitine hydrolyase proceed stereospecifically. The two isomers of l-[2-2H]carnitine were examined by 1H NMR at 500 MHz, which allowed us to independently monitor the pD dependence and coupling constants of the H-2 protons. The results obtained indicate that there is little effect of the carboxyl charge on the conformational state(s) of l-carnitine about the C-2/C-3 bond. The NMR data obtained in this study do not support previous solution studies of the pH-dependent conformational changes for dl-carnitine nor the proposed conformation of O-acetyl-dl-carnitine in the crystalline state.

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U2 - 10.1016/0003-9861(90)90750-S

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