Thus, the two substrates of this enzyme are L-cysteine and [[[enzyme]-cysteine]], whereas its two products are L-alanine and [[[enzyme]-S-sulfanylcysteine]].

This enzyme belongs to the family of transferases, specifically the sulfurtransferases, which transfer sulfur-containing groups. The systematic name of this enzyme class is L-cysteine:[enzyme cysteine] sulfurtransferase. Other names in common use include IscS, NIFS, NifS, SufS, and cysteine desulfurylase. This enzyme participates in thiamine metabolism.

As of late 2007, only one structure has been solved for this class of enzymes, with the PDB accession code 1T3I.

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