Improved high-performance liquid chromatographic method for the determination of 6-N,N,N-trimethyllysine in plasma and urine: Biomedical application of chromatographic figures of merit and amine mobile phase modifiers

Minkler, Paul E.; Erdos, Elizabeth A.; Ingalls, Stephen T.; Griffin, Ronda; Hoppel, Charles L.

doi:10.1016/s0378-4347(00)83657-9

Cited by 15 publications

(2 citation statements)

References 33 publications

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“…After protein removal from the sample, TML is purified by ionexchange chromatography followed by (ion-pair) HPLC analysis with pre-or post-column derivative formation and fluorimetric detection [82][83][84][85][86]. Agents used for the derivative formation of TML include o-phthalaldehyde [83][84][85], phenylisothiocyanate [86] and 1-fluoro-2,4-dinitrobenzene [82]. More recently, a method to measure TML in plasma by tandem MS has been described [87].…”

Section: Tmlmentioning

confidence: 99%

Carnitine biosynthesis in mammals

Vaz¹,

Wanders²

2002

Biochem. J.

449

384

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Carnitine is indispensable for energy metabolism, since it enables activated fatty acids to enter the mitochondria, where they are broken down via beta-oxidation. Carnitine is probably present in all animal species, and in numerous micro-organisms and plants. In mammals, carnitine homoeostasis is maintained by endogenous synthesis, absorption from dietary sources and efficient tubular reabsorption by the kidney. This review aims to cover the current knowledge of the enzymological, molecular, metabolic and regulatory aspects of mammalian carnitine biosynthesis, with an emphasis on the human and rat.

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Section: Tmlmentioning

confidence: 99%

Carnitine biosynthesis in mammals

Vaz¹,

Wanders²

2002

Biochem. J.

449

384

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“…Peptide-linked trimethyllysine and free trimethyllysine contents in tissues and carcass were determined by high-performance liquid chromatography (HPLC) as described by Davis et al 28 Trimethyllysine and N-acetyl-trimethyllysine content in plasma and urine were determined by HPLC as reported by Minkler et al 30 Butyrobetaine content in carcass and urine was determined by the radioenzymatic method described by Sandor et al 31 For the determination of 3-methylhistidine content, carcass, skeletal muscle, or urine was treated with 6 mol/L HCl (final concentration) at 105°C for 18 hours. 3-Methylhistidine was isolated from the resulting solution by ion-exchange chromatography and quantified by HPLC as described by Minkler et al 32 Plasma bilirubin and creatinine concentrations and activities of alkaline phosphatase and aspartate aminotransferase were determined on an S-Plus STKR autoanalyzer (Coulter Counter Instruments, Hialeah, FL).…”

Section: Materials and Equipmentmentioning

confidence: 99%

Decreased carnitine biosynthesis in rats with secondary biliary cirrhosis

2000

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Carnitine biosynthesis was investigated in rats with secondary biliary cirrhosis induced by bile duct ligation (BDL) for 4 weeks (n ‫؍‬ 5) and in pair-fed, sham-operated control rats (n ‫؍‬ 4). Control rats were pair-fed to BDL rats, and all rats were fed an artificial diet with negligible contents of carnitine, butyrobetaine, or trimethyllysine. Biosynthesis of carnitine and its precursors was determined by measuring their excretion in urine and accumulation in the body of the animals. Four weeks after BDL, total carnitine content was increased by 33% in livers from BDL rats when compared with control rats, but was unchanged in skeletal muscle and whole carcass. The plasma total carnitine concentration averaged 29.0 ؎ 4.1 vs. 46.4 ؎ 7.3 mol/L in BDL rats and control rats, respectively. Urinary total carnitine excretion was reduced by 56% in BDL rats as compared with control rats. Carnitine biosynthesis was significantly decreased in BDL rats (0.45 ؎ 0.19 vs. 0.93 ؎ 0.08 mol/100 g body weight/d in BDL and control rats, respectively). The tissue content of free and protein-linked trimethyllysine, a carnitine precursor, and trimethyllysine plasma concentrations were not different between BDL and control rats. However, urinary trimethyllysine excretion was increased 5-fold in BDL rats and approximated glomerular filtration. In contrast, urinary excretion of butyrobetaine, the direct carnitine precursor, was decreased by 40% in BDL rats as compared with control rats. Trimethyllysine biosynthesis was not different, but butyrobetaine biosynthesis was decreased by 51% in BDL as compared with control rats. In conclusion, carnitine biosynthesis is decreased in BDL rats as a result of a defect in the conversion of trimethyllysine to butyrobetaine.

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