Catalysis of nitrite generation from nitroglycerin by glyceraldehyde-3-phosphate dehydrogenase (GAPDH).
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 2.6nmolmin(-)(1)mg(-)(1) was measured for nitrite production by GAPDH from rabbit muscle and a GTN KM of 1.2mM. 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 2mM GTN for 60min 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.
Department of Chemistry and Biochemistry, Concordia University, Montreal, QC H4B 1R6, Canada.
Amedea B
AB
Seabra
Marc
M
Ouellet
Marija
M
Antonic
Michelle N
MN
Chrétien
Ann M
AM
English
D000818:Animals; D004229:Dithiothreitol / Q000494:pharmacology; D004912:Erythrocytes / Q000201:enzymology / Q000378:metabolism; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D009132:Muscles / Q000201:enzymology / Q000378:metabolism; D009243:NAD / Q000494:pharmacology; D009573:Nitrites / Q000378:metabolism*; D005996:Nitroglycerin / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D010088:Oxidoreductases / Q000187:drug effects / Q000378:metabolism; D010720:Phosphines / Q000494:pharmacology; D011817:Rabbits
D004229:Dithiothreitol; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating); D009243:NAD; D009573:Nitrites; D005996:Nitroglycerin; D010088:Oxidoreductases; D010720:Phosphines; C080938:tris(2-carboxyethyl)phosphine; C077366:glyceryl trinitrate reductase
ALDH2; Bioactivation; DTPA; Erythrocytes; G3P; GAPDH; GDN; GMN; GTN; NAD; NaPPi; Nitrite; Nitroglycerin; TCEP; aldehyde dehydrogenase-2; diethylenetriaminepentaacetic acid; glyceraldehyde-3-phosphate; glyceraldehyde-3-phosphate dehydrogenase; glyceryl dinitrate; glyceryl mononitrate; glyceryl trinitrate (nitroglycerin); heGAPDH; human erythrocyte glyceraldehyde-3-phosphate dehydrogenase; rabbit muscle glyceraldehyde-3-phosphate dehydrogenase; rmGAPDH; sodium pyrophosphate; tris(2-carboxyethyl)phosphine