Phenanthraquinone Affects Endothelial Nitric Oxide Synthase Activity through Modification of the Thiol Group: An Alternative Inhibition Mechanism.

Phenanthraquinone Affects Endothelial Nitric Oxide Synthase Activity through Modification of the Thiol Group: An Alternative Inhibition Mechanism

Phenanthraquinone (PQ) is a component of diesel exhaust particles which inhibits nitric oxide synthase (NOS) activity by shunting electrons away from the normal catalytic pathway of the enzyme and which can oxidize proximal protein sulfhydryls. In the present study, we examined the possibility that PQ may also modify critical thiol residues on endothelial NOS (eNOS), leading to a disruption of ...

Hydrogen peroxide decreases endothelial nitric oxide synthase promoter activity through the inhibition of Sp1 activity.

We have previously shown that endothelial nitric oxide synthase (eNOS) promoter activity is decreased in endothelial cells in response to the addition of hydrogen peroxide (H(2)O(2)), and this involves, at least in part, the inhibition of AP-1 activity. Thus, the objective of this study was to determine if other cis-element(s) and transcription factor(s) are involved in the oxidant-mediated dow...

Tetrahydrobiopterin and endothelial nitric oxide synthase activity.

Leptin effect on endothelial nitric oxide is mediated through Akt-endothelial nitric oxide synthase phosphorylation pathway.

Recent evidence suggests that besides its action on the central nervous system, leptin can modulate vascular tone through local mechanisms involving nitric oxide (NO) release. In this study, using a fluorescent probe for direct determination of NO, we demonstrated both in endothelial cells and in vessels that leptin is able to stimulate NO release. The effect of leptin on NO is abolished by erb...

Hyperglycemia inhibits endothelial nitric oxide synthase activity by posttranslational modification at the Akt site.

Endothelial nitric oxide synthase (eNOS) is activated by phosphorylation of serine 1177 by the protein kinase Akt/PKB. Since hyperglycemia-induced mitochondrial superoxide overproduction increases O-linked N-acetylglucosamine modification and decreases O-linked phosphorylation of the transcription factor Sp1, the effect of hyperglycemia and the hexosamine pathway on eNOS was evaluated. In bovin...