Back to deuterium: Utility of 2H-labeled peptides for targeted quantitative proteomics

Abstract

Multiple reaction monitoring mass spectrometry coupled with stable isotope dilution has become the method of choice for quantifying target proteins in complex biological samples. It quantifies signature peptides based on the sequential detection of peptide precursor ions and their fragments generated upon gas-phase collision. Heavy-isotope (13C and/or 15N) labeled peptides or proteomes are commonly used as internal reference standards for quantitation. However, use of these standards is becoming expensive when large numbers/amounts of reference peptides are needed. The search for low-cost, labeled references for proteomic quantitation such as those with 2H-labels is an object of constant pursuit. In order to take the cost advantage of 2H-labels, this work examines whether or not the known chromatographic separation of 2H-based peptides from the native counterparts affects the peptide quantitation using multiple reaction monitoring mass spectrometry. Experimental results from model peptides and proteome digests indicate that targeted mass spectrometry quantitation of the 2H- and 13C/15N-based peptides are comparable.