Affinity Selection Mass Spectrometry
Affinity Selection Mass Spectrometry
Affinity Selection Mass Spectrometry (ASMS) enables the screening of compound libraries to identify small molecules that bind directly to a target of interest. Because detection is based on target–compound binding rather than a predefined functional readout, ASMS can complement conventional biochemical and cell-based screening approaches, particularly for challenging targets.
Our platform supports a broad range of emerging therapeutic modalities and difficult target classes, including protein-protein interactions, molecular glues, chemically induced proximity (CIP), membrane proteins, transcription factors, and RNA targets. Integrated screening capabilities, advanced data analysis, and extensive compound collections help deliver reliable results, enabling confident progression to hit validation and lead optimization.
ASMS Screening for Challenging Drug Targets
Affinity Selection Mass Spectrometry (ASMS) is a label-free screening approach for identifying small molecules that bind to a target of interest. It can complement conventional screening methods, particularly when functional assays are difficult to establish or when direct binding information is valuable for hit discovery.
Our ASMS platform combines automated screening workflows, high-resolution mass spectrometry, and compound libraries to support challenging targets and discovery approaches, including protein-protein interactions, molecular glues, chemically induced proximity, membrane proteins, transcription factors, and RNA targets.
Our service is backed by access to small molecule libraries, automated operational systems, sensitive high-resolution mass spectrometry devices and efficient data-processing software.
ASMS Principle
In ASMS screening, compounds are incubated with the target, allowing binders to form target–compound complexes. Target-bound compounds are separated from unbound compounds, released from the target, and identified by mass spectrometry. This label-free approach enables direct identification of target-binding compounds from pooled compound mixtures.
ASMS Screening Workflow at WuXi Biology and Testing
The ASMS workflow integrates target preparation, compound pooling, affinity selection, mass spectrometry detection, and data analysis to identify potential binders. Primary hits can then be confirmed and prioritized through orthogonal binding or functional assays before progressing into hit validation.
Why Use ASMS for Hit Discovery?
ASMS can provide an alternative or complementary approach when conventional activity-based screening is difficult to implement. Because the assay detects target binding directly, it can be particularly useful for targets without readily available functional assays and for identifying binders that can subsequently be characterized through orthogonal assays.
WuXi Biology and Testing Compound Library for ASMS (370 K)
Our ASMS screening collection includes approximately 370,000 compounds selected to provide broad chemical diversity and drug-like physicochemical properties.
Library Features
- Library features
- Optimized diversity to maximize chemical space coverage
- WuXi Biology and Testing and commercial sources
Filtered By
- Pan Assay Interference Compounds (PAINS)
- WuXi Biology and Testing structural filters, derived from medicinal chemistry expertise
Drug-Like Property Distribution
- MW 200 ~ 500
- logP 0 ~ 5
- Hydrogen bond donors 0 ~ 5
- Hydrogen bond acceptors 0 ~ 10
- Formal charge -2 ~ 2
- Number of rotatable bonds 0 ~ 9
- PSA 10 ~ 150
- Number of heavy atoms 15 ~ 35
Physicochemical Property Distribution
Chemical Space Comparison: Drugs approved by US regulatory agencies in green, and our compound library in blue.
Comprehensive Capability and Strengths at WuXi Biology and Testing
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