Glyoxalase I is a novel nitric-oxide-responsive protein.
To clarify the molecular mechanisms of nitric oxide (NO) signalling, we examined the NO-responsive proteins in cultured human endothelial cells by two-dimensional (2D) PAGE. Levels of two proteins [NO-responsive proteins (NORPs)] with different pI values responded to NO donors. One NORP (pI 5.2) appeared in response to NO, whereas another (pI 5.0) disappeared. These proteins were identified as a native form and a modified form of human glyoxalase I (Glox I; EC 4. 4.1.5) by peptide mapping, microsequencing and correlation between the activity and the isoelectric shift. Glox I lost activity in response to NO, and all NO donors tested inhibited its activity in a dose-dependent manner. Activity and normal electrophoretic mobility were restored by dithiothreitol and by the removal of sources of NO from the culture medium. Glox I was selectively inactivated by NO; compounds that induce oxidative stress (H(2)O(2), paraquat and arsenite) failed to inhibit this enzyme. Our results suggest that NO oxidatively modifies Glox I and reversibly inhibits the enzyme's activity. The inactivation of Glox I by NO was more effective than that of glyceraldehyde-3-phosphate dehydrogenase (G3PDH), another NO-sensitive enzyme. Thus Glox I seems to be a novel NO-responsive protein that is more sensitive to NO than G3PDH.
Mitsumoto
A
A
School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641 Japan.
Kim
K R
KR
Oshima
G
G
Kunimoto
M
M
Okawa
K
K
Iwamatsu
A
A
Nakagawa
Y
Y
D018053:Arsenites / Q000494:pharmacology; D002478:Cells, Cultured; D004229:Dithiothreitol / Q000494:pharmacology; D015180:Electrophoresis, Gel, Two-Dimensional; D005978:Glutathione / Q000031:analogs & derivatives / Q000494:pharmacology; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007791:Lactoylglutathione Lyase / Q000378:metabolism*; D009569:Nitric Oxide / Q000494:pharmacology*; D009603:Nitroso Compounds / Q000494:pharmacology; D018384:Oxidative Stress; D010269:Paraquat / Q000494:pharmacology; D010449:Peptide Mapping; D026422:S-Nitrosoglutathione
D018053:Arsenites; D009603:Nitroso Compounds; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; D006861:Hydrogen Peroxide; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D007791:Lactoylglutathione Lyase; D005978:Glutathione; C015001:arsenite; D010269:Paraquat; D004229:Dithiothreitol