Carbonylated Proteins and Their Metabolic Regulation: Overview of Mechanisms, Target Proteins, and Characterization Using Proteomic Methods

Protein carbonylation is commonly accepted as biomarker of oxidative stress and is associated with a long list of pathological states and disorders. A detailed look at obesity-driven protein carbonylation illustrates the complex interplay between metabolic regulation of reactive carbonyls and other factors promoting oxidative stress and reactive oxygen species (ROS) production. Carbonylated proteins are detected using biotin-directed probes such as avidin coupled to a fluorescent reporter, which produces a carbonylation blot that may be used for general assessment of protein modification. A number of groups have described what can be termed "multifunctional" reagents for derivatizing and analyzing carbonylated proteins by mass spectrometry (MS). The multifunctional reagent possesses a number of capabilities for protein carbonylation characterization, including detection via immunoblotting, enrichment of labeled carbonylated proteins from complex mixtures, and identification and quantification of carbonyl-modified peptides using the tandem mass tag (TMT)-based functionality of the tag.