Thiol proteases: inhibitors and potential therapeutic targets.

A better understanding of the biological roles and the pathological consequences of thiol-dependent enzymes has emerged in recent years, and hence considerable progress has been made in identifying and delineating cysteine proteases that can be considered promising drug targets from those involved in housekeeping functions. Cysteine proteases have been implicated in a wide variety of disease processes ranging from cardiovascular, inflammatory, viral and immunological disorders to cancer. The first milestone in drug development of cysteine protease inhibitors has probably been reached, as IDN-6556 (a broad spectrum caspase inhibitor) has recently received Orphan Drug label by the U.

Synthesis of 3-substituted bicyclic imidazo[1,2-d][1,2,4]thiadiazoles and tricyclic benzo[4,5]imidazo[1,2-d][1,2,4]thiadiazoles.

A versatile synthetic route to potentially useful fused-ring [1,2,4]thiadiazole scaffolds (e.g., 7a and 10b) via exchange reactions of the precursor [1,2,4]thiadiazol-3-(2H)one derivatives (e.

Medicinal chemistry and properties of 1,2,4-thiadiazoles.

1,2,4-Thiadiazole is a distinctive class of small heterocyclic thiol trapping agents that serve as an interesting pharmacophore in the design of inhibitors targeting the cysteine residues of proteins. X-Ray crystal structures of enzyme-inhibitor complex indicate that the cysteine thiol reacts with the N-S bond of the thiadiazole moiety to form a disulfide bond resulting in the inactivation of the enzymes. This review addresses the medicinal chemistry and various properties of 1,2,4-thiadiazoles in their potential as new electrophilic "warheads" for targeting the cysteine residues of biomolecules (e.

3-Substituted imidazo[1,2-d][1,2,4]-thiadiazoles: a novel class of factor XIIIa inhibitors.

A new class of selective FXIIIa inhibitors with a bicyclic [1,2,4]-thiadiazole pharmacophore is described. At 160 muM, compound 8 caused 50% reduction in fibrin gamma-chain cross-linking and suppressed the polymerization of alpha chains in platelet-depleted human plasma clots. Fibrinolysis rates in response to tissue plasminogen activator were directly proportional to the concentration of 8 in plasma at the time of clotting.

1,2,4-thiadiazole: a novel Cathepsin B inhibitor.

A novel class of Cathepsin B inhibitors has been developed with a 1,2,4-thiadiazole heterocycle as the thiol trapping pharmacophore. Several compounds with different dipeptide recognition sequence (i.e.

Iron chelator research: past, present, and future.

The occurrence of in vivo iron toxicity in the human body can be categorized into iron overload and non-iron overload conditions. Iron overload conditions are common in beta-thalassemia and hereditary hemochromatosis patients, and anthracycline mediated cardiotoxicity is an example of a non-iron overload condition in cancer patients, in which the toxicity is iron-dependent. While hundreds of iron chelators have been evaluated in animal studies, only a few have been studied in humans.

Thiol-dependent enzymes and their inhibitors: a review.

Biological thiol-dependent enzymes have recently received extensive attention in the literature because of their involvement in a variety of physiopathological conditions. The active thiol groups of these enzymes are derived from the cysteine residues present. Hence, in a biological system, the selective reversible or irreversible inhibition of the activity of these enzymes by modification of the thiol moiety may potentially lead to the development of a chemotherapeutic treatment.