Alterations in Calcium-Binding Properties of Sarcoplasmic Reticulum Membrane Proteins Following Cardiac Injury

Calcium retained at binding sites of the sarcoplasmic reticulum membranes isolated from rabbit skeletal muscle requires 10-5 - 10-4 M ATP to exchange with 45Ca added to the medium. The ATP requirement for Ca exchangeability was observed with respect to the "intrinsic" Ca of the reticulum membranes and the fraction of Ca that is "actively" bound in the presence of ATP. Furthermore, a concentration of free Ca in the medium higher than 10-8 M is required for ATP to promote Ca exchangeability. This exchangeability is not influenced by caffeine, quinine, procaine, and tetracaine, and Ca that is either nonexchangeable (in the absence of ATP) or exchangeable (in the presence of ATP) is released by 1–5 mM quinine or tetracaine, but neither caffeine (6 mM) nor procaine (2–5 mM) has this effect. Quinine or tetracaine also releases Ca and Mg bound passively to the reticulum membranes. A possible role of ATP in maintaining the integrity of cellular membranes is discussed, and the effects of caffeine, quinine, and of local anesthetics on the binding of Ca by the isolated reticulum are related to the effects of these agents on 45Ca fluxes and on the twitch output observed in whole muscles.

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Purification, calcium binding properties, and ultrastructural localization of the 53,000- and 160,000 (sarcalumenin)-dalton glycoproteins of the sarcoplasmic reticulum.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)38787-3 ◽

1990 ◽

Vol 265 (17) ◽

pp. 10118-10124

Author(s):

E Leberer ◽

B G Timms ◽

K P Campbell ◽

D H MacLennan

Keyword(s):

Sarcoplasmic Reticulum ◽

Calcium Binding ◽

Ultrastructural Localization ◽

Binding Properties

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How do Ca2+ ions pass through the sarcoplasmic reticulum membrane

Bioscience Reports ◽

10.1007/bf01788369 ◽

1995 ◽

Vol 15 (5) ◽

pp. 377-385 ◽

Cited By ~ 7

Author(s):

Elisabeth Mintz ◽

Florent Guillain

Keyword(s):

Sarcoplasmic Reticulum ◽

Calcium Binding ◽

Structural Data ◽

Cytoplasmic Calcium ◽

Sarcoplasmic Reticulum Membrane ◽

Pass Through

We propose an overview of the mechanism of Ca2+ transport through the sarcoplasmic reticulum membrane via the Ca2+-ATPase. We describe cytoplasmic calcium binding, calcium occlusion in the membrane and lumenal calcium dissociation. A channel-like structure is discussed and related to structural data on the membranous domain of the Ca2+-ATPase.

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Calcium-Binding Properties of Sarcoplasmic Reticulum As Influenced by ATP, Caffeine, Quinine, and Local Anesthetics

The Journal of General Physiology ◽

10.1085/jgp.52.3.622 ◽

1968 ◽

Vol 52 (3) ◽

pp. 622-642 ◽

Cited By ~ 6

Author(s):

Arselio P. Carvalho

Keyword(s):

Skeletal Muscle ◽

Sarcoplasmic Reticulum ◽

Binding Sites ◽

Local Anesthetics ◽

Calcium Binding ◽

Rabbit Skeletal Muscle ◽

Cellular Membranes ◽

Binding Properties ◽

45Ca Fluxes

Calcium retained at binding sites of the sarcoplasmic reticulum membranes isolated from rabbit skeletal muscle requires 10-5 – 10-4 M ATP to exchange with 45Ca added to the medium. The ATP requirement for Ca exchangeability was observed with respect to the "intrinsic" Ca of the reticulum membranes and the fraction of Ca that is "actively" bound in the presence of ATP. Furthermore, a concentration of free Ca in the medium higher than 10-8 M is required for ATP to promote Ca exchangeability. This exchangeability is not influenced by caffeine, quinine, procaine, and tetracaine, and Ca that is either nonexchangeable (in the absence of ATP) or exchangeable (in the presence of ATP) is released by 1–5 mM quinine or tetracaine, but neither caffeine (6 mM) nor procaine (2–5 mM) has this effect. Quinine or tetracaine also releases Ca and Mg bound passively to the reticulum membranes. A possible role of ATP in maintaining the integrity of cellular membranes is discussed, and the effects of caffeine, quinine, and of local anesthetics on the binding of Ca by the isolated reticulum are related to the effects of these agents on 45Ca fluxes and on the twitch output observed in whole muscles.

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