Quantitative analysis of the hgh-affinity binding sites for [H-3]ouabain in the rat vas deferens and their immunological identification as the alpha(2) isoform of Na+/K+-ATPase

Quantitative analysis of the hgh-affinity binding sites for [H-3]ouabain in the rat vas deferens and their immunological identification as the alpha(2) isoform of Na+/K+-ATPase

Autor Noel, F. Google Scholar
Quintas, LEM Google Scholar
Freitas, E. Google Scholar
Caricati-Neto, A. Google Scholar
Lafayette, SSL Google Scholar
Wanderley, A. G. Google Scholar
Jurkiewicz, A. Google Scholar
Instituição Universidade Federal do Rio de Janeiro (UFRJ)
Universidade Federal de São Paulo (UNIFESP)
Resumo Binding assays were performed with [H-3]ouabain to investigate the presence of, and to characterize, a Na+/K+-ATPase isoform with high affinity for cardiac glycosides in the rat vas deferens. Nonlinear regression analysis of equilibrium experiments carried out with crude preparations in a Mg-P-i medium indicated the presence of high-affinity sites characterized with good precision (individual coefficients of variation = 11-35%) by their density (B-max = 0.42 to 0.72 pmol/mg protein) and dissociation constant (K-d = 0.069 to 0.136 mu M) values. the values of the dissociation rate constant (k(-1)) and the association rate constant (k(+1)) for these sites were 0.151 to 0.267 min(-1) and 2.87 to 3.60 mu M-1.min(-1), respectively. A higher number of low-affinity sites (K-d around 15 mu M), supposed to correspond to the alpha(1) isoform, was also identified, but their K-d and B-max values were not quantified precisely in this crude preparation. Western blot assays indicated hybridization with specific anti-alpha(1) and anti-alpha(2) isoform antibodies but not with anti-alpha(3) isoform antibody. Taken together, the present results indicate the existence of a low proportion of the alpha(2) isoform of Na+/K+-ATPase in the rat vas deferens that can be quantified precisely by [H-3]ouabain binding even in a crude membrane preparation that is suitable for studies under conditions of plasticity. (C) 1998 Elsevier Science Inc.
Palavra-chave vas deferens
ATPase, Na-K
ouabain
rat
cardiac glycoside
Idioma Inglês
Data de publicação 1998-05-01
Publicado em Biochemical Pharmacology. Oxford: Pergamon-Elsevier B.V., v. 55, n. 9, p. 1531-1535, 1998.
ISSN 0006-2952 (Sherpa/Romeo, fator de impacto)
Publicador Elsevier B.V.
Extensão 1531-1535
Fonte http://dx.doi.org/10.1016/S0006-2952(98)00013-6
Direito de acesso Acesso restrito
Tipo Artigo
Web of Science WOS:000073394500025
Endereço permanente http://repositorio.unifesp.br/handle/11600/25891

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