title: FTIR markers of methionine oxidation for early detection of oxidized protein therapeutics.
abstract: The biological activity of therapeutic proteins is strongly dependent on the stability of their folded state, which can easily be compromised by degradation. Oxidation is one of the most common causes of degradation and is typically associated with impairment of the native protein structure. Methionine residues stand out as particularly susceptible to oxidation by reactive oxygen intermediates even under mild conditions. Consequently, methionine oxidation has profound effects on protein activity up to the point of adverse biological responses. Of immediate importance therefore is finding affordable approaches for rapid detection of methionine oxidation before any substantial structural changes can ensue. Herein we report that vibrational bands at 1,044 and 1,113 cm⁻¹ in the mid-infrared region can serve as characteristic markers of methionine oxidation in oxidatively stressed protein therapeutics, monoclonal antibodies (IgG1 and its antigen-binding fragment). Such Fourier-transform infrared (FTIR) markers underpin rapid detection assays and hold particular promise for correlation of methionine oxidation with protein structure and function.
authors.affiliation: National Physical Laboratory, Hampton Road, Teddington, TW110LW, UK.
authors.forename: Jascindra
authors.initials: J
authors.lastname: Ravi
authors.forename: Anna E
authors.initials: AE
authors.lastname: Hills
authors.forename: Eleonora
authors.initials: E
authors.lastname: Cerasoli
authors.forename: Paulina D
authors.initials: PD
authors.lastname: Rakowska
authors.forename: Maxim G
authors.initials: MG
authors.lastname: Ryadnov
mesh_terms: D015415:Biomarkers / Q000032:analysis / Q000737:chemistry; D002942:Circular Dichroism / Q000379:methods; D007140:Immunoglobulin Fab Fragments / Q000032:analysis / Q000737:chemistry* / Q000627:therapeutic use; D007141:Immunoglobulin Fc Fragments / Q000032:analysis / Q000737:chemistry* / Q000627:therapeutic use; D007074:Immunoglobulin G / Q000032:analysis / Q000737:chemistry* / Q000627:therapeutic use; D008715:Methionine / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D021281:Quantitative Structure-Activity Relationship; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D015415:Biomarkers; D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; C041323:immunoglobulin Facb fragment; D008715:Methionine; C013111:methionine sulfoxide