CST, 23682S, PTMScan ® Carbamidomethyl Cysteine Motif (CAM-C) Kit

Storage
Antibody beads supplied in IAP buffer containing 50% glycerol. Store at -20°C. Do not aliquot the antibody.
Protocol
Available protocols: PTMScan
Background
Cysteine alkylation is often performed with iodoacetamide (IAA) or chloroacetamide (CAA) to generate a carbamidomethyl (CAM) modification. Because alkylation occurs on reduced cysteines, disulfide-bonded cysteines must first be treated with dithiothreitol (DTT) or another reducing agent. The alkylation reaction is irreversible. Consequently, alkylated cysteines are unable to reassociate with each other. If the sulfhydryl group of a cysteine is already modified by another compound, that cysteine will not be able to react with IAA to form the carbamidomethyl modification. The alkylation reaction is rapid, although its efficiency can be influenced by the type of denaturant used (1). Proteins are often derivatized to prevent disulfide bond scrambling, which can lead to artifactual bands in gel electrophoresis, and to minimize protease inaccessibility of cysteine-containing regions, which can limit coverage in mass spectrometry-based proteomics. In light of various studies describing potential non-cysteine reactivities of IAA and CAA and re-evaluating the effectiveness of such reactions, users should consider the benefits of cysteine derivatizations in relation to their specific experimental goals (2-4).