Data/hora: 06/06/2024 01:24:01

Provedor de dados: 	56	
País: 	Brazil	
Título: 	Ghost protein damage by peroxynitrite and its protection by melatonin	
Autores: 	Di Mascio,P.; Dewez,B.; Garcia,C.R.S.	
Data: 	2000-01-01	
Ano: 	2000	
Palavras-chave: 	Peroxynitrite; Melatonin; Spectrin; Protein; Ghost; Thiols.	
Resumo: 	We have studied the effect of peroxynitrite (ONOO-) on the membrane cytoskeleton of red blood cells and its protection by melatonin. Analysis of the protein fraction of the preparation by SDS-PAGE revealed a dose-dependent (0-600 µM ONOO-) disappearance at pH 7.4 of the main proteins: spectrin, band 3, and actin, with the concomitant formation of high-molecular weight aggregates resistant to reduction by ß-mercaptoethanol (2%) at room temperature for 20 min. These aggregates were not solubilized by 8 M urea. Incubation of the membrane cytoskeleton with ONOO- was characterized by a marked depletion of free sulfhydryl groups (50% at 250 µM ONOO-). However, a lack of effect of ß-mercaptoethanol suggests that, under our conditions, aggregate formation is not mediated only by sulfhydryl oxidation. The lack of a protective effect of the metal chelator diethylenetriaminepentaacetic acid confirmed that ONOO--induced oxidative damage does not occur only by a transition metal-dependent mechanism. However, we demonstrated a strong protection against cytoskeletal alterations by desferrioxamine, which has been described as a direct scavenger of the protonated form of peroxynitrite. Desferrioxamine (0.5 mM) also inhibited the loss of tryptophan fluorescence observed when the ghosts were treated with ONOO-. Glutathione, cysteine, and Trolox® (1 mM), but not mannitol (100 mM), were able to protect the proteins against the effect of ONOO- in a dose-dependent manner. Melatonin (0-1 mM) was especially efficient in reducing the loss of spectrin proteins when treated with ONOO- (90% at 500 µM melatonin). Our findings show that the cytoskeleton, and in particular spectrin, is a sensitive target for ONOO-. Specific antioxidants can protect against such alterations, which could seriously impair cell dynamics and generate morphological changes.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2000000100002	
Editor: 	Associação Brasileira de Divulgação Científica	
Relação: 	10.1590/S0100-879X2000000100002	
Formato: 	text/html	
Fonte: 	Brazilian Journal of Medical and Biological Research  v.33 n.1 2000	
Fonte: 	info:eu-repo/semantics/openAccess