Application of l-methionine γ-lyase in chiral amino acid analysis
Application of l-methionine γ-lyase in chiral amino acid analysis
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L-蛋氨酸γ-裂解酶在手性氨基酸分析中的应用
DOI：
10.1016/j.ab.2019.05.018
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
T.
中科院分区：
文献类型：
--
作者：
Kato;S.;Inagaki;K.;Oikawa;T.
本文将传统的手性氨基酸高效液相色谱分析方法与恶臭假单胞菌ICR 3460的L-蛋氨酸γ-裂解酶预处理相结合，对L-蛋氨酸和L-色氨酸进行了选择性分析。在L-蛋氨酸γ-裂解酶降解L-蛋氨酸后，在邻苯二甲醛和N-乙酰基-L-半胱氨酸柱前衍生化所用的标准手性氨基酸分析条件下，L-蛋氨酸与L-色氨酸共洗脱，对样品进行分析。然后将样品中的色氨酸洗脱为清晰分离的峰并进一步分析。由于l-蛋氨酸γ-裂解酶不作用于l-色氨酸，因此我们能够根据2次单独运行（含和不含l-蛋氨酸γ-裂解酶预处理的样品）获得的数据计算l-蛋氨酸或l-色氨酸浓度。根据经l-甲硫氨酸γ-裂解酶预处理的样品获得的数据计算l-色氨酸的浓度，而使用以下公式计算l-甲硫氨酸的浓度：l-甲硫氨酸浓度= {未经l-甲硫氨酸γ-裂解酶预处理的样品的数据}-{经l-甲硫氨酸γ-裂解酶预处理的样品的数据}。用该方法对含有天然氨基酸的模型样品和发酵食品样品进行了分析，计算的蛋氨酸和色氨酸浓度与理论值一致。
Here, a conventional chiral amino acid analysis method using high-performance liquid chromatography was coupled with a sample pretreatment usingl-methionine γ-lyase fromPseudomonas putidaICR 3460 for the selective analysis ofl-methionine andl-tryptophan. The sample was analyzed after the degradation ofl-methionine withl-methionine γ-lyase, asl-methionine coelutes withl-tryptophan under the standard chiral amino acid analytical conditions used for precolumn derivatization witho-phthalaldehyde andN-acetyl-l-cysteine. Thel-tryptophan in the sample was then eluted as a clearly separated peak and analyzed further. Since thel-methionine γ-lyase did not act onl-tryptophan, we were able to calculate thel-methionine orl-tryptophan concentration based on the data obtained from 2 individual runs: the sample with and withoutl-methionine γ-lyase pretreatment. The concentration ofl-tryptophan was calculated from the data obtained from the sample withl-methionine γ-lyase pretreatment, while the concentration ofl-methionine was calculated using the following equation:l-methionine concentration = {the data from the sample withoutl-methionine γ-lyase pretreatment}-{the data from the sample withl-methionine γ-lyase pretreatment}. Model samples containing authentic amino acids and a fermented food sample were analyzed by our method, and the calculated concentrations ofl-methionine andl-tryptophan were consistently in agreement with the theoretical values.