The reduction of ferryl myoglobin by ergothioneine: A novel function for ergothioneine

Abstract

In this paper, we demonstrate that ergothioneine (ES), a naturally occurring thiolhistidine, reduces ferrylmyoglobin (Mb IV) to Mb III when the former (ferryl species) is produced by exposing either deoxy Mb II or Mb III to H 2O 2. The reduction of Mb IV to Mb III by ES yields the disulflde of ES which the addition of GSH promptly reduces back to ES. The addition of ES (100 μ m) in the perfusion buffer of Langendorff rat heart preparations exposed to a brief period of ischemia prevents the myocardial damage (lactate dehydrogenase release) which accompanies reperfusion. The results of these experiments support a view that ES and its redox couple GSH might function in a Mb redox cycle.