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

Author Noel, François Google Scholar
Quintas, Luis Eduardo M Google Scholar
Freitas, Eliana Google Scholar
Caricati-Neto, Afonso Autor UNIFESP Google Scholar
Lafayette, Simone S L Autor UNIFESP Google Scholar
Wanderley, Almir G. Autor UNIFESP Google Scholar
Jurkiewicz, Aron Autor UNIFESP Google Scholar
Institution Universidade Federal do Rio de Janeiro (UFRJ)
Universidade Federal de São Paulo (UNIFESP)
Abstract 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.
Keywords vas deferens
ATPase, Na-K
ouabain
rat
cardiac glycoside
Language English
Date 1998-05-01
Published in Biochemical Pharmacology. Oxford: Pergamon-Elsevier B.V., v. 55, n. 9, p. 1531-1535, 1998.
ISSN 0006-2952 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 1531-1535
Origin http://dx.doi.org/10.1016/S0006-2952(98)00013-6
Access rights Closed access
Type Article
Web of Science ID WOS:000073394500025
URI http://repositorio.unifesp.br/handle/11600/25891

Show full item record




File

File Size Format View

There are no files associated with this item.

This item appears in the following Collection(s)

Search


Browse

Statistics

My Account