Related Experiment Video
Updated: Jun 5, 2026

Antimicrobial Peptides Produced by Selective Pressure Incorporation of Non-canonical Amino Acids
Published on: May 4, 2018
Cutting Edge: Coding single nucleotide polymorphisms of endoplasmic reticulum aminopeptidase 1 can affect antigenic
Irini Evnouchidou1, Ram P Kamal, Sergey S Seregin
1Protein Chemistry Laboratory, National Centre for Scientific Research Demokritos, Agia Paraskevi, Athens 15310, Greece.
Abstract:
ER aminopeptidase 1 (ERAP1) customizes antigenic peptide precursors for MHC class I presentation and edits the antigenic peptide repertoire. Coding single nucleotide polymorphisms (SNPs) in ERAP1 were recently linked with predisposition to autoimmune disease, suggesting a link between pathogenesis of autoimmunity and ERAP1-mediated Ag processing. To investigate this possibility, we analyzed the effect that disease-linked SNPs have on Ag processing by ERAP1 in vitro. Michaelis-Menten analysis revealed that the presence of SNPs affects the Michaelis constant and turnover number of the enzyme. Strikingly, specific ERAP1 allele-substrate combinations deviate from standard Michaelis-Menten behavior, demonstrating substrate-inhibition kinetics; to our knowledge, this phenomenon has not been described for this enzyme. Cell-based Ag-presentation analysis was consistent with changes in the substrate inhibition constant K(i), further supporting that ERAP1 allelic composition may affect Ag processing in vivo. We propose that these phenomena should be taken into account when evaluating the possible link between Ag processing and autoimmunity.
Related Concept Videos
RNA Editing
Leaky Scanning
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Protein Modifications in the RER
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Signal Sequences and Sorting Receptors
Protein Folding Quality Check in the RER

