ESI Proteomics
ESI proteomics is a method in proteomics research that leverages ESI technology. This technique involves using a high-voltage electric field to transform protein solutions into charged microdroplets. These droplets convert into gas-phase ions upon desolvation, facilitating efficient ionization and mass spectrometric analysis of proteins and peptides. As a "soft ionization" technology, ESI excels in preserving the structural integrity of macromolecules like proteins, while offering high sensitivity in detection.
In practical applications, ESI proteomics enables the multidimensional analysis of protein functional networks. Clinically, it aids in the early diagnosis and prognosis of diseases by analyzing disease-specific protein biomarkers—such as cancer-related antigens or inflammatory factors—in serum or tissue samples. For instance, the increased detection of specific glycosylated proteins in the blood of colorectal cancer patients is a marker for liquid biopsy. In drug development, ESI proteomics elucidates drug target mechanisms and potential off-target effects by comparing proteomic changes in cells before and after drug administration, allowing for the identification of candidate drug-binding proteins and early warning of toxic reactions. In microbiology, this technology assists in profiling pathogen resistance proteins, supporting the design of new antibiotics. Moreover, ESI has advanced comparative proteomic studies across species, such as analyzing milk protein compositions in different mammals to trace functional adaptations throughout evolution.
The technological advancement of ESI proteomics is attributed to its distinctive workflow. Initially, samples undergo enzymatic digestion to produce peptide mixtures, which are then separated through liquid chromatography to reduce complexity. During ionization, ESI employs high voltage to form charged microdroplets from peptides in the mobile phase. As the solvent evaporates, the microdroplets shrink, increasing charge density, ultimately leading peptides to enter the mass spectrometer as singly or multiply charged ions. This process is particularly suited for analyzing high molecular weight proteins and offers better compatibility with acid-sensitive proteins compared to other ionization methods like MALDI. In data analysis, database matching and quantitative algorithms enable the identification and relative abundance calculation of thousands of proteins simultaneously. For example, in research on neurodegenerative diseases, ESI proteomics has been used to identify over 300 differentially expressed proteins in the cerebrospinal fluid of Alzheimer's patients, with the abnormal phosphorylation of tau protein serving as a crucial marker for disease staging.
Currently, innovations in ESI proteomics focus on enhancing resolution and throughput. The development of high-resolution mass spectrometers, such as the Orbitrap series, has achieved single amino acid-level accuracy in identifying post-translational modification sites, including phosphorylation and ubiquitination. On the throughput front, Data-Independent Acquisition (DIA) technology facilitates large-scale clinical cohort proteomic analyses. During the COVID-19 pandemic, global multi-center studies applied ESI proteomics to systematically analyze immune-related protein dynamics in patient blood, uncovering the link between complement system overactivation and severe pneumonia, thus providing a theoretical basis for targeted therapy. Additionally, the rise of spatially resolved proteomics, integrating ESI with microdissection techniques, allows precise mapping of protein expression profiles within specific tumor microenvironment regions.
As a leading entity in proteomics, MtoZ Biolabs is dedicated to innovation and service enhancement. Our comprehensive proteomics analysis platform addresses the full spectrum of needs from sample preparation and mass spectrometry to bioinformatics interpretation.
MtoZ Biolabs, an integrated chromatography and mass spectrometry (MS) services provider.
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