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标题：Fluorometric Determination of L-Tryptophan with Methoxyacetaldehyde
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作者：Hideaki IIZUKA ; Takehiko YAJIMA
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：1993
卷号：16
期号：2
页码：103-106
DOI：10.1248/bpb.16.103
出版社：The Pharmaceutical Society of Japan
摘要：It was observed in our laboratory that methoxyacetaldehyde induced strong fluorescence with L-tryptophan in the presence of NaNO₂ at pH 2.75. The reaction mixture was heated at 80°C for 15 min and the fluorescence was measured at the excitation wavelength, 253 nm and the emission, 450 nm. Amino acids other than L-tryptophan did not produce fluorescence under the conditions employed. A good linear working curve was observed between 25 pmol/50 μl and 500 pmol/50 μl of L-tryptophan. The limit of determination for L-tryptophan was 10 pmol/50 μl. The coefficient of variation of the measurements (n=5) was 1.5% for 250 pmol/50 μl of L-tryptophan. The proposed method was successfully applied to the analyses of tryptophan in a pooled human serum. Total tryptophan was determined after deproteinization with trichloroacetic acid, and free tryptophan was determined using the ultrafiltrate of a pooled human serum. Analytical recoveries of total and free tryptophan were 98.8% and 99.1%, respectively. The fluorescent products of L-tryptophan and methoxyacetaldehyde were characterized as β-carboline and 1-methoxymethyl-β-carboline by the use of liquid chromatography-mass spectrometry (LC-MS) and HPLC.
关键词：L-tryptophan;serum;fluorometry;methoxyacetaldehyde;β-carboline;1-methoxymethyl-β-carboline