title: A new dimethyl labeling-based SID-MRM-MS method and its application to three proteases involved in insulin maturation.
abstract: The absolute quantification of target proteins in proteomics involves stable isotope dilution coupled with multiple reactions monitoring mass spectrometry (SID-MRM-MS). The successful preparation of stable isotope-labeled internal standard peptides is an important prerequisite for the SID-MRM absolute quantification methods. Dimethyl labeling has been widely used in relative quantitative proteomics and it is fast, simple, reliable, cost-effective, and applicable to any protein sample, making it an ideal candidate method for the preparation of stable isotope-labeled internal standards. MRM mass spectrometry is of high sensitivity, specificity, and throughput characteristics and can quantify multiple proteins simultaneously, including low-abundance proteins in precious samples such as pancreatic islets. In this study, a new method for the absolute quantification of three proteases involved in insulin maturation, namely PC1/3, PC2 and CPE, was developed by coupling a stable isotope dimethyl labeling strategy for internal standard peptide preparation with SID-MRM-MS quantitative technology. This method offers a new and effective approach for deep understanding of the functional status of pancreatic β cells and pathogenesis in diabetes.
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.|University of Chinese Academy of Sciences, Beijing, 100049 China.
authors.forename: Dongwan
authors.initials: D
authors.lastname: Cheng
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.
authors.forename: Li
authors.initials: L
authors.lastname: Zheng
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Hou
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.
authors.forename: Jifeng
authors.initials: J
authors.lastname: Wang
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.
authors.forename: Peng
authors.initials: P
authors.lastname: Xue
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.
authors.forename: Fuquan
authors.initials: F
authors.lastname: Yang
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.
authors.forename: Tao
authors.initials: T
authors.lastname: Xu
keywords: Dimethyl labeling; Insulin; Mass spectrometry; Stable isotope dilution-multiple reaction monitoring (SID-MRM)