干热条件下形成的磷酸化多肽的质谱分析

Mass Spectral Analysis of Phosphorylated Peptides Formed under Dry Heating Conditions

建立两个含有丝氨酸(S)、苏氨酸(T)和酪氨酸(Y)的多肽模型(肽A和肽B),采用傅里叶变换离子回旋共振质谱(FT-ICR MS)和电喷雾-电子转移裂解质谱(LTQ-ETD MS-MS)对干热条件下得到的磷酸化多肽进行研究。FT-ICR MS分析得出,肽A和肽B在该条件下均引入一个磷酸根;LTQ-ETD MS-MS分析得出,肽A的S和Y被修饰的特征峰较明显,而T被修饰的特征峰与Y被修饰的部分特征峰相重叠,无法判断T是否被磷酸化修饰;磷酸化肽B中仅含有S和T,S具有非常明显的修饰特征峰,而无T被修饰的特征峰。结果表明,S和Y在干热条件下比T更易被磷酸化修饰,这可能与3种氨基酸支链上羟基位置有关。

Two peptide models such as peptide A and peptide B containing serine（S）,threonine（T） and tyrosine（Y） were built.The phosphorylation of both peptides was carried out under dry heating conditions.The phosphorylation sites were determined using FT-ICR MS and LTQ-ETD MS/MS.FT-ICR analysis revealed one phosphorlyated site in either peptide under dry heating conditions.In addition,LTQ-ETD MS/MS analysis revealed obvious characteristic peaks of phosphorylated S and Y in peptide A.It was difficult to determine the phosporlyation of T due to the overlapped characteristic peaks of phosphorylated Y and T.However,the LTQ-ETD MS/MS spectrum of peptide B only revealed the phosphorylation of S without the phosphorylation of T.In summary,S and Y were easier to be phosphorylated than T in the same peptide under dry heating conditions.