title: Homocysteine effects on cellular glutathione peroxidase (GPx-1) activity under in vitro conditions.
abstract: Hyperhomocysteinemia is associated with a lot of diseases including cardiovascular diseases and neural tube defect, but it has not been clarified exactly which mechanism is responsible for occurence disease. Here, homocysteine (Hcy) and cysteine (Cys), which are thiol containing amino acids, were examined for their effect on glutathione peroxidase (GPx) activity. It was observed that the GPx-1 activity was inhibited under severe hyperhomocysteinemia (50-500 microM Hcy) conditions, especially at low glutathione concentrations but that cysteine increased GPx-1 activity at low glutathione concentrations and inhibition clearly appeared at 500 microM Cys concentration.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Cukurova University, Adana, Turkey. aysendurmaz@yahoo.com
authors.forename: Ayşen
authors.initials: A
authors.lastname: Durmaz
authors.forename: Nurten
authors.initials: N
authors.lastname: Dikmen
mesh_terms: D000818:Animals; D002384:Catalysis; D002417:Cattle; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005979:Glutathione Peroxidase / Q000378:metabolism*; D006710:Homocysteine / Q000494:pharmacology*; D009249:NADP / Q000378:metabolism; D000094765:Glutathione Peroxidase GPX1
chemical_list: D004791:Enzyme Inhibitors; D006710:Homocysteine; D009249:NADP; D005979:Glutathione Peroxidase; D000094765:Glutathione Peroxidase GPX1