Identification of new medium‐chain acylcarnitines present in urine of a patient with medium‐chain acyl‐CoA dehydrogenase deficiency

Libert, R.; Hoof, F. Van; Thillaye, M; Vincent, Marie‐Françoise; Nassogne, Marie‐Cécile; Stroobant, Vincent; Hoffmann, Edmond de; Schanck, André

doi:10.1023/a:1005482828392

Cited by 10 publications

(6 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These two compounds would then be converted into acylcarnitines and excreted. cis-3,4-Methylene-nonanoylcarnitine has been reported in human urine [7]. We also have observed this compound in human urine [unpublished data including comparison to synthesized standard], further supporting the above proposal.…”

Section: The Likely Source Of Cis-34-methyleneheptanoylcarnitinesupporting

confidence: 86%

“…Our GC/MS spectrum of "C8:1" acyl picolinyl ester is similar to that shown by Libert [7]. The mass difference of 13 units between m/z 165 ion and m/z 178 ion in the GC/MS spectrum of "C8:1" acyl picolinyl ester is similar in part to the observation reported for the picolinyl derivative of 11,12-methylene-octadecanoic acid [21].…”

Section: Characterization Of Urinary "C8:1" Acylcarnitine By Gc/mssupporting

confidence: 86%

“…Determination of the chemical structure of the acyl group of an acylcarnitine could suggest the original source of the acylcarnitine's acyl group. One unusual acylcarnitine reported is cis-3,4-methylene-heptanoylcarnitine [7]. To determine if this identification is correct, a human urine sample containing "C8:1" acylcarnitine was collected.…”

Section: "C8:1" Acylcarnitine In Human Urinementioning

confidence: 99%

“…Libert et al [7] reported that "C8:1" acylcarnitine in normal human urine is cis-3,4-methylene-heptanoylcarnitine, although only indirect evidence was presented. Our GC/MS spectrum of "C8:1" acyl picolinyl ester is similar to that shown by Libert [7].…”

Section: Characterization Of Urinary "C8:1" Acylcarnitine By Gc/msmentioning

confidence: 99%

“…One of these is a so-called "C8:1" acylcarnitine, which Libert et al identified as cis-3,4-methylene-heptanoylcarnitine [7].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

cis-3,4-Methylene-heptanoylcarnitine: Characterization and verification of the C8:1 acylcarnitine in human urine

Yang

Minkler

Hoppel

2007

Journal of Chromatography B

View full text Add to dashboard Cite

Section: The Likely Source Of Cis-34-methyleneheptanoylcarnitinesupporting

confidence: 86%

Section: Characterization Of Urinary "C8:1" Acylcarnitine By Gc/mssupporting

confidence: 86%

Section: "C8:1" Acylcarnitine In Human Urinementioning

confidence: 99%

Section: Characterization Of Urinary "C8:1" Acylcarnitine By Gc/msmentioning

confidence: 99%

“…One of these is a so-called "C8:1" acylcarnitine, which Libert et al identified as cis-3,4-methylene-heptanoylcarnitine [7].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

cis-3,4-Methylene-heptanoylcarnitine: Characterization and verification of the C8:1 acylcarnitine in human urine

Yang

Minkler

Hoppel

2007

Journal of Chromatography B

View full text Add to dashboard Cite

Identification of ethylsuccinylcarnitine present in some human urines

Libert

Hoof

Laus³

et al. 2005

Clinica Chimica Acta

View full text Add to dashboard Cite

Picolinyl ester fragmentation mechanism studies with application to the identification of acylcarnitine acyl groups following transesterification

Yang

Minkler

Hoppel

et al. 2006

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

Acyl picolinyl esters provide excellent data to identify the structures of acyl groups. However, the mechanisms for the formation of fragment ions from picolinyl esters are unsettled. Proposed structures for fragment ions have focused on long-chain groups and may not accommodate results from medium-and short-chain acyl groups. Using deuterium-labeled organic acids, we have investigated the mechanisms for the formation of fragment ions. Based on these studies, we propose a new mechanism that is consistent with the experimental data. We then tested the mechanisms by analyzing selected acylcarnitines. Transesterification of acylcarnitines was performed by reaction with 3-pyridylcarbinol and potassium tert-butoxide in dichloromethane to produce acyl picolinyl esters. The picolinyl esters were separated and detected by gas chromatography/electron ionization-mass spectrometry. Each mass spectrum contained a series of peaks with m/z differences of 12, 13, or 14 u depending on the acyl group's chemical structure. [4] in which the fragment ions of an acyl picolinyl ester result from the interaction of alkyl hydrogens with the ionized nitrogen on the pyridine ring. The mechanism invoking a McLafferty rearrangement, proposed by Harvey for the formation of the fragment ions from long-chain acyl groups, is not supported by data from Christie's laboratory [4, 5]. Furthermore, these mechanistic studies have not been conducted using either short-or medium-chain acyl groups.Acyl group identification is an important component in many analytical methods. Several reports detail procedures to identify the acyl groups of acylcarnitines.Lowes and Rose [6,7] reported that by converting acylcarnitines into acyloxylactones, partial, but not complete, structural information of the acyl group was obtained. Libert et al. [8 -10] used a procedure whereby acylcarnitines were extracted from urine and hydrolyzed, followed by conversion of the organic acids into acyl picolinyl esters. These acyl picolinyl esters were then characterized by GC/MS, which provided better structural data than in the case of acyloxylactones. However, the presence of organic acids in urine makes questionable the interpretation of the source of acyl groups as being exclusively from acylcarnitines. Although acyl picolinyl esters usually are produced from organic acids, transesterification has been reported to produce acyl picolinyl esters from lipids by direct reaction with 3-pyridylcarbinol, thus eliminating the need to hydrolyze the lipids first [11].In this paper, we propose mechanisms for the formation of the fragment ions of acyl picolinyl esters based on experiments using deuterium-labeled organic acids. We applied these results to the characterization of acyl groups of several acylcarnitine species following their transesterification to acyl picolinyl esters. The transesterification was performed by reacting acylcarnitines with 3-pyridylcarbinol and potassium tert-

show abstract

Identification of new medium‐chain acylcarnitines present in urine of a patient with medium‐chain acyl‐CoA dehydrogenase deficiency

Cited by 10 publications

References 10 publications

cis-3,4-Methylene-heptanoylcarnitine: Characterization and verification of the C8:1 acylcarnitine in human urine

cis-3,4-Methylene-heptanoylcarnitine: Characterization and verification of the C8:1 acylcarnitine in human urine

Identification of ethylsuccinylcarnitine present in some human urines

Picolinyl ester fragmentation mechanism studies with application to the identification of acylcarnitine acyl groups following transesterification

Contact Info

Product

Resources

About