Nitric Oxide-Induced Modification of Glyceraldehyde-3-Phosphate Dehydrogenase with NAD⁺ Is Not ADP-Ribosylation

Abstract

One biological effect of nitric oxide (NO) has been believed to be exerted through induction of the ADP-ribosyltransferase activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Though this notion is based on the finding that NO increases the auto-ADP-ribosylation of GAPDH, controversial data have also been reported. To determine whether or not NO really activates ADP-ribosylation, we re-examined the NO-induced modification of GAPDH with NAD⁺. GAPDH was modified equally with [adenosine-¹⁴C]NAD⁺ and [carbonyl-¹⁴C]NAD⁺, indicating that the glycoside bond of NAD⁺ between ADP-ribose and nicotinamide is intact. The release of nicotinamide from NAD⁺ was not evident during incubation of GAPDH with [carbonyl-₁₄C]NAD⁺. Thus, the modification of GAPDH is apparently not ADP-ribosylation. In addition, we found that basal and glyceraldehyde-3-phosphate-induced modifications of GAPDH, both of which have also been explained as ADP-ribosylation, were not ADP-ribosylation, and that the modification of GAPDH in the absence and presence of NO or GA3P wadistinct in the dithiothreitol effect or resistance to HgCl₂.