Recognition and quantification of binary and ternary mixtures of isomeric peptides by the kinetic method: metal ion and ligand effects on the dissociation of metal-bound complexes
Recognition and quantification of binary and ternary mixtures of isomeric peptides by the kinetic method: metal ion and ligand effects on the dissociation of metal-bound complexes
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DOI：
10.1016/s1044-0305(02)00868-1
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发表时间：
2003-02
影响因子：
3.2
通讯作者：
Lianming Wu;K. Lemr;T. Aggerholm;R. Cooks
中科院分区：
文献类型：
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作者：
Lianming Wu;K. Lemr;T. Aggerholm;R. Cooks
动力学方法应用于区分和定量的异构三肽的混合物的基础上的二价金属离子结合的簇在离子阱质谱仪的竞争性解离。该方法进一步扩展到确定异构体Gly-Gly-Ala（GGA）、Ala-Gly-Gly（AGG）和Gly-Ala-Gly（GAG）的三元混合物的组成。该程序还允许对光学异构体的三元混合物进行手性定量。二价金属离子CaII特别适合于同量异位三肽Gly-Gly-Leu/Gly-Gly-Ile（GGL/GGI）的异构体区分和定量。在第一行过渡金属离子中，CuII产生非常有效的异构体分化的同量异位三肽，GGI/GGL使用GAG作为参考配体，和位置异构体GAG/GGA使用GGI作为参考配体。这可能是由于agostic键合：α-agostic键合发生在Cu II和GAG之间，β-agostic键合发生在Cu II和GGI之间，每种键合对Cu II结合的二聚体簇的稳定性产生较大但不同的空间效应。这些数据形成了将来可能定量分析较大肽混合物的基础，例如在肽和肽模拟物的组合合成中产生的混合物。
The kinetic method is applied to differentiate and quantify mixtures of isomeric tripeptides based on the competitive dissociations of divalent metal ion-bound clusters in an ion trap mass spectrometer. This methodology is extended further to determine compositions of ternary mixtures of the isomers Gly-Gly-Ala (GGA), Ala-Gly-Gly (AGG), and Gly-Ala-Gly (GAG). This procedure also allows to perform chiral quantification of a ternary mixture of optical isomers. The divalent metal ion CaIIis particularly appropriate for isomeric distinction and quantification of the isobaric tripeptides Gly-Gly-Leu/Gly-Gly-Ile (GGL/GGI). Among the first-row transition metal ions, CuIIyields remarkably effective isomeric differentiation for both the isobaric tripeptides, GGI/GGL using GAG as the reference ligand, and the positional isomers GAG/GGA using GGI as the reference ligand. This is probably due to agostic bonding: α-agostic bonding occurs between CuIIand GAG and β-agostic bonding between CuIIand GGI, each produces large but different steric effects on the stability of the CuII-bound dimeric clusters. These data form the basis for possible future quantitative analyses of mixtures of larger peptides such as are generated, for example, in combinatorial synthesis of peptides and peptide mimics.