Department of Chemistry, Seoul National University, Seoul, Republic of Korea.
Anal Biochem. 2011 Jul 15;414(2):294-6. doi: 10.1016/j.ab.2011.03.032. Epub 2011 Mar 29.
Determination of the phosphorylation site in peptides by conventional tandem mass spectrometry is subject to ambiguity due to the neutral loss of the phosphate groups, especially in multiphosphorylated peptides. To prevent the neutral loss, the phosphate groups in phosphoserine or phosphothreonine peptides were replaced by p-bromobenzyl mercaptan via β-elimination and Michael addition. The unique isotopic signature of the Br introduced facilitated definitive localization of phosphorylation sites in multiphosphorylated peptides with highly adjacent serine or threonine residues. This method could be used to confirm phosphorylation sites determined by conventional tandem mass spectrometry after phosphopeptide enrichment.
通过传统的串联质谱法测定肽中的磷酸化位点，由于磷酸基团的中性丢失，特别是在多磷酸化肽中，会存在歧义。为了防止中性丢失，通过β-消除和迈克尔加成，将丝氨酸或苏氨酸肽中的磷酸基团用对溴苄基巯基取代。引入的 Br 的独特同位素特征有助于在高度相邻的丝氨酸或苏氨酸残基存在的情况下，明确鉴定多磷酸化肽中的磷酸化位点。这种方法可用于在磷酸肽富集后，确认传统串联质谱法测定的磷酸化位点。
