ICP-MS for multiplex absolute determinations of proteins.

Area of Science:

• Analytical Chemistry
• Biochemistry
• Mass Spectrometry

Background:

• Proteomics increasingly relies on quantitative measurements to understand biological systems.
• Current methods primarily offer relative protein quantification, limiting precise biological state assessment.
• Absolute protein quantification is crucial for accurate biomarker analysis and biological interpretation.

Purpose of the Study:

• To explore the potential of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for absolute protein quantification.
• To discuss methods for multiplexed protein and enzyme activity determinations using ICP-MS.
• To highlight the integration of ICP-MS multi-element capabilities with separation techniques for advanced proteomics.

Main Methods:

• Utilizing ICP-MS as a complementary ion source to MALDI- and ESI-MS for absolute protein quantification via heteroelement detection.
• Investigating liquid sample nebulization and laser direct sampling for multiplexed protein analysis with ICP-MS.
• Exploring the combination of ICP-MS with multi-analyte separation techniques like HPLC and multiplex immunoassays.

Main Results:

• ICP-MS offers robust, accurate, and precise absolute quantification of proteins through heteroelement measurement.
• Current ICP-MS applications for protein quantification are limited to single-heteroatom measurements, underutilizing its multi-element capacity.
• Reported approaches demonstrate the feasibility of multiplexed protein and enzyme activity determinations using ICP-MS.

Conclusions:

• ICP-MS holds significant promise for advancing absolute and multiplexed quantitative proteomics.
• Integrating ICP-MS's multi-isotopic analysis with separation techniques can enable simultaneous quantification of multiple proteins and enzyme activities.
• Future interdisciplinary developments are expected in multiplexed quantitative targeted proteomics using ICP-MS.