title: N-nitrosomelatonin outcompetes S-nitrosocysteine in inhibiting glyceraldehyde 3-phosphate dehydrogenase: first evidence that N-nitrosomelatonin can modify protein function.
abstract: Low-molecular-weight S-nitrosothiols (RSNOs) are well known for their capability to transnitrosate cysteine residues of enzymes thereby altering their catalytic activity. It is unknown, however, whether N-nitrosomelatonin (NOMela) which is highly effective in transnitrosating low-molecular-weight thiols (RSHs) can also alter protein function. In the present study, we report on such a capability with glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as a target enzyme. Reaction of NOMela with GAPDH resulted in an increase of RSNOs at the expense of RSHs. Somewhat surprisingly, NOMela was about 10-fold more effective than S-nitrosocysteine in inhibiting GAPDH. Vitamin C and glutathione increased the NOMela-dependent inhibition of the enzyme by accelerating the intermediacy of nitroxyl which is also highly effective in nitrosating RSHs. The occurrence of this intermediate during the NOMela-vitamin C reaction was verified by using Mn(III)-tetrakis(1-methyl-4-pyridyl)porphorin pentachloride as nitroxyl scavenger. The NOMela-dependent inactivation of GAPDH was so effective that this reaction can be used to quantify NOMela with high sensitivity.
authors.affiliation: Institut für Physiologische Chemie, Universitätsklinikum Essen, Essen, Germany. michael.kirsch@uni-duisburg-essen.de
authors.forename: Michael
authors.initials: M
authors.lastname: Kirsch
authors.forename: Herbert
authors.initials: H
authors.lastname: de Groot
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology; D003545:Cysteine / Q000031:analogs & derivatives* / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000737:chemistry; D005978:Glutathione / Q000494:pharmacology; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) / Q000037:antagonists & inhibitors*; D008301:Maleimides; D008550:Melatonin / Q000031:analogs & derivatives* / Q000494:pharmacology; D008665:Metalloporphyrins / Q000737:chemistry; D009589:Nitrogen Oxides / Q000032:analysis; D009603:Nitroso Compounds / Q000494:pharmacology*; D026403:S-Nitrosothiols / Q000494:pharmacology*; D013438:Sulfhydryl Compounds / Q000378:metabolism*
chemical_list: C504424:Alexa Fluor 488 C5-maleimide; D016166:Free Radical Scavengers; D008301:Maleimides; D008665:Metalloporphyrins; C503522:N1-nitrosomelatonin; D009589:Nitrogen Oxides; D009603:Nitroso Compounds; D026403:S-Nitrosothiols; D013438:Sulfhydryl Compounds; C050950:tetrakis(N-methyl-4-pyridiniumyl)porphine manganese(III) complex; C021315:S-nitrosocysteine; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating); D005978:Glutathione; C039900:nitroxyl; D008550:Melatonin; D003545:Cysteine; D001205:Ascorbic Acid