Glutathione: is it an evolutionary vestige of the penicillins?

Glutathione is structurally similar to the precursor of the antibiotics found in the fungi of the genus Penicillium and Cephalosporium. The structural similarity is such to permit the rearrangement of glutathione to form the beta-lactam ring, common to many antibiotics. The possibility exists that glutathione may have evolved away from an antibiotic role in cells with the evolutionary development of specialized cells of immune systems.