Detection of diastereomer peptides as the intermediates generating D-amino acids during acid hydrolysis of peptides
Detection of diastereomer peptides as the intermediates generating D-amino acids during acid hydrolysis of peptides
复制标题
检测肽酸水解过程中生成 D-氨基酸的中间体非对映异构体肽
DOI：
10.1007/s00726-016-2304-2
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发表时间：
2016
期刊：
影响因子：
3.5
通讯作者：
H.
中科院分区：
文献类型：
--
作者：
Miyamoto;T.;Sekine;M.;Ogawa;T.;Hidaka;M.;Watanabe;H.;Homma;H.;Masaki;H.
在这项研究中，我们研究了在酸水解的早期阶段，肽内的氨基酸残基是否被异构化（和肽转化为非对映异构体）。我们证明，模型二肽l-Ala-l-Phe和l-Phe-l-Ala差向异构化，以产生相应的非对映异构体在非常早期的阶段，在其酸水解裂解为氨基酸之前。此外，通过在水解孵育期间形成二酮哌嗪产生序列反转的二肽，并且这些二肽也被差向异构化。在孵育0.5 - 2 h期间，非对映异构体的比例迅速增加。在酸水解过程中，模型二肽的C-末端残基比N-末端残基更快地异构化，这与通过0 h-外推法测定的C-末端残基的d-氨基酸值大于N-末端残基的d-氨基酸值的观察结果一致。因此，由0 h外推法测定的人工氨基酸含量似乎是酸水解过程中氨基酸残基异构化的产物。
In this study, we investigated whether the amino acid residues within peptides were isomerized (and the peptides converted to diastereomers) during the early stages of acid hydrolysis. We demonstrate that the model dipeptidesl-Ala-l-Phe andl-Phe-l-Ala are epimerized to produce the corresponding diastereomers at a very early stage, prior to their acid hydrolytic cleavage to amino acids. Furthermore, the sequence-inverted dipeptides were generated via formation of a diketopiperazine during hydrolytic incubation, and these dipeptides were also epimerized. The proportion of diastereomers increased rapidly during incubation for 0.5–2 h. During acid hydrolysis, C-terminal residues of the model dipeptides were isomerized faster than N-terminal residues, consistent with the observation that thed-amino acid values of the C-terminal residues determined by the 0 h-extrapolating method were larger than those of the N-terminal residues. Thus, the artificiald-amino acid contents determined by the 0 h-extrapolating method appear to be products of the isomerization of amino acid residues during acid hydrolysis.