Properties of selected S-nitrosothiols compared to nitrosylated WR-1065.
WR-1065 ([N-mercaptoethyl]-1-3-diaminopropane), the active form of the aminothiol drug Ethyol/Amifostine, protects against toxicity caused by radiation, chemotherapy and endotoxin. Because WR-1065 and other thiols readily bind nitric oxide (NO), injurious conditions or therapies that induce the production or mobilization of NO could alter the effects of WR-1065. S-Nitrosothiols were prepared from various thiols by a standard method to compare properties and stability. Heteromolecular quantum correlation 2D nuclear magnetic resonance was used to characterize nitrosylated glutathione (GSH) and WR-1065; both S- and N-nitrosothiols were observed, depending on the experimental conditions. Three categories of S-nitrosothiol stability were observed: (1) highly stable, with t(1/2) > 8 h, N-acetyl-L-cysteine nitrosothiol (t(1/2) 15 h) > GSH nitrosothiol (t(1/2) 8 h); (2) intermediate stability, t(1/2) approximately 2 h, cysteamine nitrosothiol and WR-1065 nitrosothiol; and (3) low stability, t(1/2) < 1 h, cysteine nitrosothiol and Captopril nitrosothiol. Similar relative rates were observed for Hg(+2)-induced denitrosylation: WR-1065 reacted faster than GSH nitrosothiol, while GSH nitrosothiol reacted faster than N-acetyl-L-cysteine nitrosothiol. Mostly mediated by mixed-NPSH disulfide formation, the activity of the redox-sensitive cysteine protease, cathepsin H, was inhibited by the S-nitrosothiols, with WR-1065 nitrosothiol > cysteine nitrosothiol > N-acetyl-L-cysteine nitrosothiol and GSH nitrosothiol. These observations indicate that, relative to other nitrosylated non-protein thiols, the S-nitrosothiol of WR-1065 is an unstable non-protein S-nitrosothiols with a high reactive potential in the modification of protein thiols.
Whiteside
William Michael
WM
University of Illinois at Chicago, Department of Chemistry, Chicago, Illinois 60612, USA.
Sears
Devin N
DN
Young
Paul R
PR
Rubin
David B
DB
D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D056655:Cathepsin H; D002403:Cathepsins / Q000378:metabolism; D002417:Cattle; D003546:Cysteine Endopeptidases / Q000378:metabolism; D004229:Dithiothreitol / Q000494:pharmacology; D004355:Drug Stability; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008624:Mercaptoethylamines / Q000737:chemistry* / Q000494:pharmacology; D008958:Models, Molecular; D009603:Nitroso Compounds / Q000737:chemistry*; D011837:Radiation-Protective Agents / Q000737:chemistry* / Q000494:pharmacology; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry
D008624:Mercaptoethylamines; D009603:Nitroso Compounds; D011837:Radiation-Protective Agents; D013438:Sulfhydryl Compounds; C020174:N-(2-mercaptoethyl)-1,3-diaminopropane; D012710:Serum Albumin, Bovine; D002403:Cathepsins; D003546:Cysteine Endopeptidases; D056655:Cathepsin H; D001205:Ascorbic Acid; D004229:Dithiothreitol