Binding of GSH at the active site of mLTC4S.

<p>A. Electron density 2fo-fc map contoured at 1.0 σ around GSH with Arg104 coordinating the sulfur in GSH. B. GSH bound at the active site, coordinated by several amino acids where the Arg51 - Tyr50 (indicated with a line) interaction in the human enzyme, is lost in the mLTC4S, which has a Phe in position 50.