A pyrazinoindole with a disulfide bridge spanning a dioxo-substituted pyrazine ring; mycotoxin produced by several species of fungi. ChEBI: Gliotoxin is a pyrazinoindole with a disulfide bridge spanning a dioxo-substituted pyrazine ring; mycotoxin produced by several species of fungi. It has a role as a mycotoxin, an immunosuppressive agent, an EC 2.5.1.58 (protein farnesyltransferase) inhibitor, a proteasome inhibitor and an antifungal agent. It is an organic disulfide, a pyrazinoindole, an organic heterotetracyclic compound and a dipeptide.