Glutathione can occur in reduced (GSH), oxidized (GSSG), or in mixed disulfide forms and is ubiquitous in multiple biological systems serving as the major thiol-disulfide redox buffer of the cell. GSSG is the oxidized form of GSH . It can be reduced back to GSH through the NADPH-dependent enzyme glutathionereductase. GSSG functions as a hydrogen acceptor in the enzymatic determination of NADP+ and NADPH and can be a proximal donor in S-glutathionylation post translational modifications. The ratio of reduced glutathione to oxidized glutathione within cells is often used as an indicator of oxidative stress, with higher concentrations of GSSG predicting increased oxidative stress.
(E)-Ajoene is a disulfide that has been found inA. sativumand has diverse biological activities.1,2,3,4It is active against Gram-positive and Gram-negative bacteria (MICs = 10-250 and 150->500 μg/ml, respectively) and fungi (MICs = 15-50 μg/ml).1(E)-Ajoene inhibits proliferation of a variety of cancer cells, including MDA-MB-231 breast, HeLa cervical, and WHCO1 esophageal cancer cells (IC50s = 18.6, 61, and 39.2 μM, respectively).2It also inhibits human glutathionereductase andT. cruzitrypanothione reductase when used at a concentration of 200 μM.3(E)-Ajoene (25 mg/kg) is neuroprotective in a gerbil model of ischemia-reperfusion injury, reducing reactive astrocytosis and microgliosis in the hippocampal CA1 region.4 1.Yoshida, H., Iwata, N., Katsuzaki, H., et al.Antimicrobial activity of a compound isolated from an oil-macerated garlic extractBiosci. Biotechnol. Biochem.62(5)1014-1017(1998) 2.Kaschula, C.H., Hunter, R., Hassan, H.T., et al.Anti-proliferation activity of synthetic ajoene analogues on cancer cell-linesAnticancer Agents Med. Chem.11(3)260-266(2011) 3.Gallwitz, H., Bonse, S., Martinez-Cruz, A., et al.Ajoene is an inhibitor and subversive substrate of human glutathionereductase and Trypanosoma cruzi trypanothione reductase: Crystallographic, kinetic, and spectroscopic studiesJ. Med. Chem.42(3)364-372(1999) 4.Yoo, D.Y., Kim, W., Nam, S.M., et al.Neuroprotective effects of Z-ajoene, an organosulfur compound derived from oil-macerated garlic, in the gerbil hippocampal CA1 region after transient forebrain ischemiaFood Chem. Toxicol.721-7(2014)
Thioredoxin reductase peptide, corresponding to residues 53–67 in thioredoxin reductase (TrxR), is used in thioredoxin reductase research. Mammalian thioredoxin reductase (TR) catalyzes the reduction of the redox-active disulfide bond of thioredoxin (Trx) and is essential for cellular redox homeostasis.