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No. 8 (PC 8)
Development of the enzymatic method of serum ethanolamine and examination of
its clinical utility
E. Ohta (1) , E.Hokazono (1) , M.Ono (2) , T.Hotta (2) , S.Osawa (3) , Y.Kayamori (1)
1
Division of Medical Technology, Department of Health Sciences, Graduate school of
Medicine, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Japan
2
Department of Clinical Chemistry and Laboratory Medicine, Kyushu University
Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Japan 3 Division of Clinical
Laboratory Science, Department of Medical Risk And Crisis Management, Chiba
Institute of Science, 15-8 Shiomi-cho, Choshi, Chiba, Japan
Ethanolamine (EA) is mainly hydrolyzed from phosphatidyl ethanolamine (PE) by phospholipase D
(PLD) in vivo. A study reported that urine EA increased in newborns as Zellweger syndrome, a
congenital metabolic disease, but its concentration in blood and clinical significance in adults were not
clarified. Recently, a metabolomics study using mass spectrometry reported that EA in saliva of
pancreatic cancer patients increased significantly. Therefore, our purposes are to develop a rapid and
simple enzymatic method with an amine oxidase involving copper from Arthrobacter sp. (AAO) (EC
1.4.3.6) and to examine the clinical meaning of EA in serum. In our measurement method, reagent 1
(R-1) contained 0.1 mol/L HEPES buffer (pH 8.2 at 25ºC), 1.6 mmol/L TOOS, 5.0 kU/L POD, 1.12
mmol/L N-ethylmaleimide, 16.8 kU/L L-ascorbate oxidase (ASOD) and 7.47 mmol/L NaN3. Reagent 2
(R-2) contained 0.1 mol/L HEPES buffer (pH 8.2 at 25ºC), 20.0 kU/L AAO and 0.4 mmol/L
4-aminoantipyrine. The assay used a Hitachi 7170 type analyzer. A 10 µL specimen was mixed with 180
µL R-1; after incubation for 5 min at 37 ºC, 90 µL R-2 was added; after another 5 min, the mixture was
measured using a 2-point end assay performed at 37 ºC, with wavelengths of 700/546 (sub/main
wavelength). The within-run CVs of the present method with three kinds of EA solutions ranged
0.43-7.13% (n=10). The standard curve showed linearity from 0 to 800 µmol/L. Analytical recovery was
98.4%. The reference interval of EA in normal was 8.17 ± 4.83 µmol/L (n=19). EA in hepatocellular
carcinoma patient sera was significantly higher than normal. In conclusion, our method for serum EA is
suitable for routine clinical use in the laboratory for determination of accuracy and simplicity. We
consider EA in serum may be a new biomarker of hepatocellular carcinoma.
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