1. Catalysis of nitrite generation from nitroglycerin by glyceraldehyde-3-phosphate dehydrogenase (GAPDH)
- Author
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Michelle N. Chretien, Amedea B. Seabra, Marc Ouellet, Marija Antonic, and Ann M. English
- Subjects
Cancer Research ,Erythrocytes ,Phosphines ,Physiology ,Clinical Biochemistry ,Dehydrogenase ,Biochemistry ,Dithiothreitol ,Nitroglycerin ,chemistry.chemical_compound ,stomatognathic system ,medicine ,Animals ,Humans ,Nitrite ,Nitrites ,Glyceraldehyde 3-phosphate dehydrogenase ,ALDH2 ,biology ,Chemistry ,Muscles ,NAD ,Kinetics ,Disulfiram ,cardiovascular system ,biology.protein ,Rabbits ,Glyceraldehyde 3-phosphate ,NAD+ kinase ,Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) ,Oxidoreductases ,circulatory and respiratory physiology ,medicine.drug - Abstract
Vascular relaxation to nitroglycerin (glyceryl trinitrate; GTN) requires its bioactivation by mechanisms that remain controversial. We report here that glyceraldehyde-3-phosphate dehydrogenase (GAPDH) catalyzes the release of nitrite from GTN. In assays containing dithiothreitol (DTT) and NAD+, the GTN reductase activity of purified GAPDH produces nitrite and 1,2-GDN as the major products. A vmax of 2.6 nmol min−1 mg−1 was measured for nitrite production by GAPDH from rabbit muscle and a GTN KM of 1.2 mM. Reductive denitration of GTN in the absence of DTT results in dose- and time-dependent inhibition of GAPDH dehydrogenase activity. Disulfiram, a thiol-modifying drug, inhibits both the dehydrogenase and GTN reductase activity of GAPDH, while DTT or tris(2-carboxyethyl)phosphine reverse the GTN-induced inhibition. Incubation of intact human erythrocytes or hemolysates with 2 mM GTN for 60 min results in 50% inhibition of GAPDH’s dehydrogenase activity, indicating that GTN is taken up by these cells and that the dehydrogenase is a target of GTN. Thus, erythrocyte GAPDH may contribute to GTN bioactivation.
- Published
- 2013