Difference in the sensitivity of junctional and longitudinal sarcoplasmic reticulum Ca(2+)-ATPase to ADP
Braz. j. med. biol. res
;
25(11): 1113-6, 1992. graf
Artículo
en Inglés
| LILACS
| ID: lil-134607
RESUMO
The Ca2+ release mechanism that triggers muscle contraction is still not completely understood. We compared Ca2+ accumulation and acetyl phosphate hydrolysis by the Ca(2+)-ATPases present in the longitudinal and junctional membrane of the sarcoplasmic reticulum of rabbit skeletal muscle and found that Ca(2+)-ATPase is more sensitive to ADP inhibition when the enzyme is located on the junctional membrane than when the enzyme is located on the longitudinal membrane (K0.5 = 144 microM for the junctional enzyme vs K0.5 = 415 microM for the longitudinal enzyme). When the enzyme was solubilized in non-ionic detergent (2% v/v Triton X-100) and tested again using 2 mM AcP as substrate, the difference in ADP sensitivity observed with native preparations disappeared. We conclude that the enzyme is regulated differently depending on its localization on the membrane of the sarcoplasmic reticulum
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Índice:
LILACS (Américas)
Asunto principal:
Retículo Sarcoplasmático
/
Adenosina Difosfato
Tipo de estudio:
Estudio diagnóstico
Límite:
Animales
Idioma:
Inglés
Revista:
Braz. j. med. biol. res
Asunto de la revista:
Biologia
/
Medicina
Año:
1992
Tipo del documento:
Artículo
/
Congreso y conferencia
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