Subscribe to Newsletter
Techniques & Tools Mass Spectrometry

Discovering ERAP1 Inhibitors with MALDI-TOF MS

The dysregulation of endoplasmic reticulum aminopeptidase 1 (ERAP1) protein has been linked to cancer and both autoinflammatory and autoimmune diseases – making it a conspicuous therapeutic target for drug discovery. Existing high-throughput screening campaigns – such as fluorescence and chemiluminescence methods – are used to target specific proteins in a sea of interfering compounds. Unfortunately, these labed-based methods are susceptible to artifacts, and can often result in perturbed biology. 

A group of UK researchers decided to tackle these challenges by developing a high-throughput MALDI-TOF mass spectrometry (MS) assay to screen for small molecule inhibitors of ERAP1 (1). They based their assay on the existing in vitro RapidFire MS (RF MS) assay for greater reproducibility and robustness for the platform. The label-free nature of the assay was particularly valuable in the case of ERAP1, considering enzyme activity is mediated by the substrate’s structural features. 

The team discovered that the previous RF MS peptides – YTAFTIPSI substrate trimmed into the product TAFTIPSI – had low ionization efficiency and assay stability. Therefore, arginine residues were added into the peptide sequence to increase the limit and linearity of detection. The assay conditions were optimized and then validated with established ERAP1 inhibitors that targeted the active side of the enzyme.

Using their novel MALDI-TOF MS process, the researchers tested a set of 699 ERAP1 binders that had been previously identified through an affinity selection mass spectrometry screen. They first tested the compounds at a single concentration, before moving onto a dose-response format. The team compared the collection of compounds found using the new setup with the existing RF MS setup, noting that both platforms delivered similar results; however, the authors state that their MALDI-TOF MS setup saw additional benefits, such as shorter sample cycle times, lower reagent consumption, and a lower tight-binding limit – making it an effective candidate for ERAP1 screening.

Receive content, products, events as well as relevant industry updates from The Analytical Scientist and its sponsors.
Stay up to date with our other newsletters and sponsors information, tailored specifically to the fields you are interested in

When you click “Subscribe” we will email you a link, which you must click to verify the email address above and activate your subscription. If you do not receive this email, please contact us at [email protected].
If you wish to unsubscribe, you can update your preferences at any point.

  1. L. Müller et al., SLAS Discov, 28, 3 (2022). PMID: 36414185
About the Author
Georgia Hulme

Georgia Hulme is Associate Editor at The Analytical Scientist

Related Application Notes
Revolutionizing PFAS Detection in Air: High Sensitivity with the Aim Reactor

| Contributed by TOFWERK

Detection of ozone-depleting substances and halogenated GHGs in industrial zones with a cryogen-free preconcentration–GC–MS system

| Contributed by Markes International Ltd

Room temperature and sensitive analysis of haloanisoles in wine using Vacuumassisted headspace SPME with GC/ECD

| Contributed by Markes International Ltd

Related Product Profiles
Higher Peaks – Clearly.

| Contributed by Shimadzu Europa

Compact with countless benefits

| Contributed by Shimadzu Europa

The fine Art of Method Development

| Contributed by Shimadzu Europa

Register to The Analytical Scientist

Register to access our FREE online portfolio, request the magazine in print and manage your preferences.

You will benefit from:
  • Unlimited access to ALL articles
  • News, interviews & opinions from leading industry experts
  • Receive print (and PDF) copies of The Analytical Scientist magazine