Mass spectrometry in coupling with affinity capture-release and isotope-coded affinity tags for quantitative protein...

Area of Science:

• Biochemistry
• Analytical Chemistry
• Molecular Biology

Background:

• Affinity capture-release electrospray ionization mass spectrometry (ACESIMS) and isotope-coded affinity tags (ICAT) are advanced techniques for protein quantitation.
• Both methods employ biotinylated tags for selective conjugate capture from complex biological samples.
• Stable heavy isotopes are utilized as internal standards for accurate quantification in both approaches.

Purpose of the Study:

• To introduce and detail the ACESIMS and ICAT techniques for protein activity and content analysis.
• To highlight the application of ACESIMS in clinical enzymology for diagnosing genetic diseases.
• To showcase the utility of ICAT in functional proteomics for determining protein expression levels.

Main Methods:

• ACESIMS targets specific cellular enzymes using synthetic substrate conjugates for activity measurement.
• ICAT involves selective conjugation of cysteine thiols, followed by enzymatic digestion and mass spectrometry.
• Both techniques leverage affinity capture and stable isotope labeling for quantitative analysis.

Main Results:

• Multiplex determination of enzyme activities via ACESIMS facilitates the diagnosis of lysosomal storage diseases.
• ICAT enables quantitative analysis of peptide conjugates, providing insights into protein expression.
• Applications include molecular-level diagnosis of genetic disorders and protein quantification in cellular studies.

Conclusions:

• ACESIMS and ICAT are powerful tools for quantitative proteomics and clinical enzymology.
• These methods offer high selectivity and accuracy in analyzing complex biological mixtures.
• Their applications span from diagnosing genetic diseases to understanding cellular protein dynamics.