Interactions of the regulatory ligands Mg2+ and MgATP2- with the renal plasma membrane Ca(2+)-ATPase: effects of osmolytes that stabilize or destabilize protein structure
Braz. j. med. biol. res
; 26(4): 373-81, Apr. 1993. ilus, graf
Artigo
em Inglês
| LILACS
| ID: lil-148748
Biblioteca responsável:
BR1.1
RESUMO
In this report we analyze the kinetics of activation of the plasma membrane Ca(2+)-ATPase from kidney proximal tubules by the regulatory ligands Mg2+ and MgATP2-, and we examine modifications in the effects of these ligands that are promoted by organic solutes of natural occurrence that stabilize or destabilize protein structure and function. The solutes tested were trimethylamine-N-oxide (TMA-O), sucrose and urea. TMA-O and sucrose were chosen as representative of the different methylamines and polyols, respectively, that accumulate in living organisms. The results lead to the conclusion that free Mg2+ and the MgATP2- complex both activate the rate-determining E2-->E1 transition during the catalytic cycle of the enzyme, by binding to nonidentical and independent regulatory sites. They also indicate that TMA-O, sucrose and urea not only promote global modifications in the enzyme structure, but also modify specific interactions of the ligands Mg2+ and MgATP2- at their regulatory sites
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Coleções:
Bases de dados internacionais
Base de dados:
LILACS
Assunto principal:
Técnicas In Vitro
/
Trifosfato de Adenosina
/
ATPases Transportadoras de Cálcio
/
Túbulos Renais Proximais
/
Magnésio
Limite:
Animais
Idioma:
Inglês
Revista:
Braz. j. med. biol. res
Assunto da revista:
Biologia
/
Medicina
Ano de publicação:
1993
Tipo de documento:
Artigo
/
Congresso e conferência