Figure 2: Proteomic techniques to profile Zn²⁺ biochemistry of proteins.

A) Alkylating probes, such as iodoacetamide and N-ethylmaleimide, react with free thiols but not those complexed with Zn²⁺. Protein samples are then subjected to gel-based and/or proteomic analyses. B) AIZin permeates cell membranes and its electrophilicity is enhanced upon Zn²⁺ binding. When in proximity to a nucleophilic amino acid, the nucleophile attacks AIZin and the acyl group is transferred to the protein along with its fluorescein cargo. Researchers can then perform subsequent enrichment (via immunoprecipitation) and proteomic analysis.