ID BETA ASP & GAMMA GLU PEPTIDE LINKS BY ESI & MALDI PSD OF CHARGED DERIVATIVES

β-天冬氨酸(b-Asp)和谷氨酸(g-Glu) 残基是形成肽键的氨基酸残基。 通过侧链上的羧酸基团而不是在 阿尔法碳(正常)。天冬氨酸的形式(正常-天冬氨酸与 多肽中的B-天冬氨酸)对多肽的活性有很大影响； 同样，谷氨酸的形式(正常-Glu与G-Glu)会影响 多肽活性。我们可以确定天冬氨酸的类型或 用MALDI-PSD分析谷氨酸键的存在 TMPP-Ac-衍生物。含有A的多肽的质谱图 侧链连接残基(b-Asp或g-Glu)具有b型离子峰， 比相应的b型离子峰更强烈 含有正常残基(天冬氨酸或谷氨酸)的多肽的光谱。 对模型多肽的成对异构体的实验正在研究中 努力建立有用的协议来识别 未知数。

Beta-aspartic acid (b-Asp) and gamma-glutamic acid (g-Glu) residues are amino acid residues in which the peptide bond is formed through the carboxylic acid group on the side chain rather than at the alpha carbon (normal). The form of aspartic acid (normal-Asp vs. b-Asp) in a peptide can greatly affect the activity of the peptide; likewise, the form of glutamic acid (normal-Glu vs. G-Glu) affects the peptide activity. We can identify the type of aspartic acid or glutamic acid linkage present by using analysis by MALDI-PSD of the TMPP-Ac-derivatives. The mass spectrum of the peptide containing a side chain-linked residue (b-Asp or g-Glu) had a b-type ion peak that was more intense than the corresponding b-type ion peak in the spectrum of the peptide containing the normal residue (Asp or Glu). Experiments with paired isomers of model peptides are being studied in an effort to establish useful protocols for identification of unknowns.