IUBMB Enzyme Nomenclature


Accepted name: γ-glutamyl hercynylcysteine S-oxide synthase

Reaction: hercynine + γ-L-glutamyl-L-cysteine + O2 = γ-L-glutamyl-S-(hercyn-2-yl)-L-cysteine S-oxide + H2O

For diagram of reaction click here.

Glossary: hercynine = Nα,Nα,Nα-trimethyl-L-histidine

Other name(s): EgtB

Systematic name: hercynine,γ-L-glutamyl-L-cysteine:oxygen oxidoreductase [γ-L-glutamyl-S-(hercyn-2-yl)-L-cysteine S-oxide-forming]

Comments: Requires Fe2+ for activity. The enzyme, found in bacteria, is specific for both hercynine and γ-L-glutamyl-L-cysteine. It is part of the biosynthesis pathway of ergothioneine.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:


1. Seebeck, F.P. In vitro reconstitution of Mycobacterial ergothioneine biosynthesis. J. Am. Chem. Soc. 132 (2010) 6632-6633. [PMID: 20420449]

2. Pluskal, T., Ueno, M. and Yanagida, M. Genetic and metabolomic dissection of the ergothioneine and selenoneine biosynthetic pathway in the fission yeast, S. pombe, and construction of an overproduction system. PLoS One 9 (2014) e97774. [PMID: 24828577]

[EC created 2015]

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