Simple and Sensitive Analysis for Dried Blood Spot Proteins by Sodium Carbonate Precipitation for Clinical Proteomics

Dried
blood spots (DBS) are widely used for screening biomolecular
profiles, including enzymatic activities. However, detection of minor
proteins in DBS by liquid chromatography–mass spectrometry
(LC-MS/MS) without pre-enrichment remains challenging because of the
coexistence of large quantities of hydrophilic proteins. In this study,
we address this problem by developing a simple method using sodium
carbonate precipitation (SCP). SCP enriches hydrophobic proteins from
DBS, allowing substantial removal of soluble proteins. In combination
with SCP, we used quantitative LC-MS/MS proteome analysis in a data-independent
acquisition mode (DIA) to enhance the sensitivity and quantification
limits of proteome analysis. As a result, identification of 1977 proteins
in DBS is possible, including 585 disease-related proteins listed
in the Online Mendelian Inheritance in Man.