ISSN: 1300-0292
İndekslendiği Dizinler: SCIENCE CITATION INDEX EXPANDED
CINAHL, Index Copernicus,
Chemical Abstracts (CA),
Excerpta Medica / EMBASE
Dil: Türkçe, İngilizce
İçerik: Orijinal Araştırma, Derleme, Editöre Mektup, Olgu Sunumu, Tıp Eğitimi, Tıbbi Kitap İncelemeleri
|
|
|
|
An Improved Radioisotopic Assay For The Determination Of Free And Esterified Carnitine In Serum And Urine
Feza GÜNERAL*
*Doç.Dr.Hacettepe University, Institute of Child Health, Department of Pediatric Nutrition and Metabolism, ANKARA
An improved radioisotopic assay adapted to the determination of L-carnitine and acylcarnitines in biological samples is described. The applicability of the assay to both normal and pathological conditions due to carnitine deficiency is discussed.
The use of N-ethylmaleimide as trapping agent has been shown to have no inhibition on carnitine acetyltransferase and the kinetic constant has been calculated (Km=28). The superiority of this compound over other trapping agents has been discussed. Several modifications have been assayed and optimum recovery rates (99.7-100.1%) were obtained with: a) N-ethylmaleimide used in a much lower concentration than other methods, b) a mixture of 14C acetly CoA and non-labeled acetyl CoA in a ratio of 21 to 5.6 mg, c) Carnitine acetyltransferase used in lower activitiy, d) Herpes buffer at a lower pH, e) The introduction of a correction factor for the calculation of total carnitine, f) a standard solution of L-acetyl carnitine run through the extraction procedure, g) 3 times extraction on ice following Dowex addition. The assay was applied to serum and urine samples of 15 healthy children and of 7 children with organic acidemias and hypotonia. The within assay coefficient of variation (CV%) was 1.3±0.15 and the within day CV% was 1.9+0.2. The possibility of accurately quantifying a carnitine content as low as 50 picomoles with high recovery and precision without any interference from acetylcarnitines, makes this assay eminently suitable for the study of patients with abnormal carnitine metabolism and excretion.
Keywords: Carnitine acetyltransferase, Acylcarnitines,
Organic acidemias, N-Ethylmaleimide
Turkiye Klinikleri J Med Sci 1996, 16:355-359
|
|
|
|
|
