Generation of thiyl radical by nitric oxide: a spin trapping study

1998 ◽  
pp. 1507-1512 ◽  
Author(s):  
Sovitj Pou ◽  
Gerald M. Rosen
Keyword(s):  
Nitric Oxide ◽  
Spin Trapping ◽  
Thiyl Radical

scholarly journals Nitric oxide-dependent NAD linkage to glyceraldehyde-3-phosphate dehydrogenase: possible involvement of a cysteine thiyl radical intermediate

1996 ◽  
Vol 319 (2) ◽  
pp. 369-375 ◽  
Author(s):  
Maurizio MINETTI ◽  
Donatella PIETRAFORTE ◽  
A. M. Michela DI STASI ◽  
Cinzia MALLOZZI
Keyword(s):  
Nitric Oxide ◽  
Free Radical ◽  
Active Site ◽  
Superoxide Radical ◽  
Spin Trapping ◽  
Cysteine Residue ◽  
Thiyl Radical ◽  
Radical Intermediate ◽  
No Donors ◽  
High Enzyme

Previous studies have demonstrated that glyceraldehyde-3-phosphate dehydrogenase (GAPDH) undergoes NAD(H) linkage to an active site thiol when it comes into contact with •NO-related oxidants. We found that a free-radical generator 2,2´-azobis-(2-amidinopropane) hydrochloride (AAPH), which does not release either •NO or •NO-related species, was indeed able to induce the NAD(H) linkage to GAPDH. We performed spin-trapping studies with purified apo-GAPDH to identify a putative thiol intermediate produced by AAPH as well as by •NO-related oxidants. As •NO sources we used •NO gas and two •NO-donors, S-nitroso-N-acetyl-D,L-penicillamine and 3-morpholinosydnonimine hydrochloride (SIN-1). Because SIN-1 produces •NO and a superoxide radical simultaneously, we also tested the effects of peroxynitrite. All the •NO-related oxidants were able to induce the linkage of NAD(H) to GAPDH and the formation of a protein free-radical identified as a thiyl radical (inhibited by N-ethylmaleimide). •NO gas and the •NO-donors required molecular oxygen to induce the formation of the GAPDH thiyl radical, suggesting the possible involvement of higher nitrogen oxides. Thiyl radical formation was decreased by the reconstitution of GAPDH with NAD+. Apo-GAPDH was a strong scavenger of AAPH radicals, but its scavenging ability was decreased when its cysteine residues were alkylated or when it was reconstituted with NAD+. In addition, after treatment with AAPH, a thiyl radical of GAPDH was trapped at high enzyme concentrations. We suggest that the NAD(H) linkage to GAPDH is mediated by a thiyl radical intermediate not specific to •NO or •NO-related oxidants. The cysteine residue located at the active site of GAPDH (Cys-149) is oxidized by free radicals to a thiyl radical, which reacts with the neighbouring coenzyme to form Cys-NAD(H) linkages. Studies with the NAD+ molecule radiolabelled in the nicotinamide or adenine portion revealed that both portions of the NAD+ molecule are linked to GAPDH.

In Vivo Spin Trapping of Glyceryl Trinitrate–Derived Nitric Oxide in Rabbit Blood Vessels and Organs

Circulation ◽  
1995 ◽  
Vol 92 (7) ◽  
pp. 1876-1882 ◽  
Author(s):  
Alexander Mülsch ◽  
Peter Mordvintcev ◽  
Eberhard Bassenge ◽  
Frank Jung ◽  
Bernd Clement ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Glyceryl Trinitrate ◽  
Blood Vessels ◽  
Spin Trapping ◽  
Rabbit Blood

scholarly journals Investigation of the existence and biological role of l-arginine/nitric oxide pathway in human platelets by spin-trapping/EPR studies

1991 ◽  
Vol 202 (3) ◽  
pp. 923-930 ◽  
Author(s):  
Laszlo PRONAI ◽  
Kohji ICHIMORI ◽  
Hiroyuki NOZAKI ◽  
Hiroe NAKAZAWA ◽  
Haruka OKINO ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Human Platelets ◽  
Spin Trapping ◽  
Biological Role ◽  
Nitric Oxide Pathway

scholarly journals Spin trapping of nitric oxide produced in vivo in septic-shock mice

FEBS Letters ◽  
1994 ◽  
Vol 345 (2-3) ◽  
pp. 120-124 ◽  
Author(s):  
Ching-San Lai ◽  
Andrei M. Komarov
Keyword(s):  
Nitric Oxide ◽  
Septic Shock ◽  
Spin Trapping
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