An Attempt to Quantitative Analysis for Clinical Proteomics by Two-dimensional Electrophoresis and MALDI-TOF-MS Using Stable Isotope-labeled Small Organic Molecules

摘要

Quantitative analysis of proteins is essential to proteomics. By modifying specific amino acid residues with stable isotope-labeled or -unlabeled reagents followed by two-dimensional (2D) electrophoresis and MALDI-TOF-MS, it is possible to quantitatively analyze the relative abundance of two tryptic peptides hence proteins based on the ratio of the relative peak intensities between the two peptides modified with isotope-labeled and -unlabeled reagents. We have now developed a protocol for quantitative analysis of such peptides by MALDI-TOF-MS using synthetic iodoacetanilide (IAA) and ~(13)C_(7)-labeled iodoacetoanilide (~(13)C_(7)-IAA) which specifically react with sulfhydryl groups in cysteine residues. We also show that this technique can be applied to quantitative analysis of synthetic peptides and proteins extracted from patient sera and separated on 2D electrophoresis.