OX133, a monoclonal antibody recognizing protein-bound N-ethylmaleimide for the identification of reduced disulfide bonds in proteins |
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Authors: | Lisa-Marie Holbrook Lai-Shan Kwong Clive L. Metcalfe Emmanuel Fenouillet Ian M. Jones |
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Affiliation: | 1. Sir William Dunn School of Pathology, University of Oxford, Oxford, UK;2. School of Biological Sciences, University of Reading, UK;3. CNRS, Institut des Sciences Biologiques, Marseille, France;4. School of Biological Sciences, University of Reading, UK |
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Abstract: | In vivo, enzymatic reduction of some protein disulfide bonds, allosteric disulfide bonds, provides an important level of structural and functional regulation. The free cysteine residues generated can be labeled by maleimide reagents, including biotin derivatives, allowing the reduced protein to be detected or purified. During the screening of monoclonal antibodies for those specific for the reduced forms of proteins, we isolated OX133, a unique antibody that recognizes polypeptide resident, N-ethylmaleimide (NEM)-modified cysteine residues in a sequence-independent manner. OX133 offers an alternative to biotin-maleimide reagents for labeling reduced/alkylated antigens and capturing reduced/alkylated proteins with the advantage that NEM-modified proteins are more easily detected in mass spectrometry, and may be more easily recovered than is the case following capture with biotin based reagents. |
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Keywords: | Allosteric detection disulfide bond labile maleimide reduction |
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