In Vitro Production of Ergothioneine Isotopologues

Abstract Ergothioneine is an emerging component of the redox homeostasis system in human cells and in microbial pathogens, such as Mycobacterium tuberculosis and Burkholderia pseudomallei . The synthesis of stable isotope‐labeled ergothioneine derivatives may provide important tools for deciphering the distribution, function, and metabolism of this compound in vivo. We describe a general protocol for the production of ergothioneine isotopologues with programmable 2 H, 15 N, 13 C, 34 S, and 33 S isotope labeling patterns. This enzyme‐based approach makes efficient use of commercial isotope reagents and is also directly applicable to the synthesis of radio‐isotopologues.