Binding and Release of Cations by Sarcoplasmic Reticulum before and after Removal of Lipid
Autor(a) principal: | |
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Data de Publicação: | 1972 |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10316/8347 https://doi.org/10.1111/j.1432-1033.1972.tb01865.x |
Resumo: | The Ca2+ bound actively in the presence of ATP by sarcoplasmic reticulum isolated from rabbit skeletal muscle is released by Zn2+ (or Cd2+) as well as by phospholipases A or C and by trypsin. Zinc ions also release Mg2+ and are taken up passively by the reticulum membranes, whereas phospholipases A and C and trypsin release only the actively bound Ca2+. Phospholipase A, and to a smaller extent phospholipase C and trypsin, increase the passive cation-binding capacity of reticulum. Thus, concurrently with the loss of selectively bound Ca2+ caused by these agents, there is an increase in the passively bound Mg2+. The increase in the passive cation-binding capacity of reticulum induced by phospholipase depends on the presence of the splitting products of phospholipids, since their removal when digested reticulum is washed with a 2.5% albumin solution decreases the binding capacity to about 50% of the original value. When Ca2+, Mg2+ or Sr2+ is bound passively by reticulum, the ratio of H+ released to either of these divalent cations bound, expressed in terms of nequiv H+ released per nequiv divalent cation bound is about 1.0, but when Zn2+ is taken up, the ratio H+/Zn2+ is only about 0.5, which suggests that some of the Zn2+ is bound at sites that do not release H+ or bind Ca2+. After lipid extraction with 90% acetone, the cation-binding capacity and H+ release are decreased to about 40% of the original values. This effect is particularly evident between pH values of about 6.0 and 8.0. The apparent passive Ca2+-binding affinity is not affected by the lipid removal. |
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Binding and Release of Cations by Sarcoplasmic Reticulum before and after Removal of LipidThe Ca2+ bound actively in the presence of ATP by sarcoplasmic reticulum isolated from rabbit skeletal muscle is released by Zn2+ (or Cd2+) as well as by phospholipases A or C and by trypsin. Zinc ions also release Mg2+ and are taken up passively by the reticulum membranes, whereas phospholipases A and C and trypsin release only the actively bound Ca2+. Phospholipase A, and to a smaller extent phospholipase C and trypsin, increase the passive cation-binding capacity of reticulum. Thus, concurrently with the loss of selectively bound Ca2+ caused by these agents, there is an increase in the passively bound Mg2+. The increase in the passive cation-binding capacity of reticulum induced by phospholipase depends on the presence of the splitting products of phospholipids, since their removal when digested reticulum is washed with a 2.5% albumin solution decreases the binding capacity to about 50% of the original value. When Ca2+, Mg2+ or Sr2+ is bound passively by reticulum, the ratio of H+ released to either of these divalent cations bound, expressed in terms of nequiv H+ released per nequiv divalent cation bound is about 1.0, but when Zn2+ is taken up, the ratio H+/Zn2+ is only about 0.5, which suggests that some of the Zn2+ is bound at sites that do not release H+ or bind Ca2+. After lipid extraction with 90% acetone, the cation-binding capacity and H+ release are decreased to about 40% of the original values. This effect is particularly evident between pH values of about 6.0 and 8.0. The apparent passive Ca2+-binding affinity is not affected by the lipid removal.1972info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10316/8347http://hdl.handle.net/10316/8347https://doi.org/10.1111/j.1432-1033.1972.tb01865.xengEuropean Journal of Biochemistry. 27:3 (1972) 491-502Carvalho, Arsélio P.info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2020-05-29T09:41:55Zoai:estudogeral.uc.pt:10316/8347Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T20:55:37.954496Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Binding and Release of Cations by Sarcoplasmic Reticulum before and after Removal of Lipid |
title |
Binding and Release of Cations by Sarcoplasmic Reticulum before and after Removal of Lipid |
spellingShingle |
Binding and Release of Cations by Sarcoplasmic Reticulum before and after Removal of Lipid Carvalho, Arsélio P. |
title_short |
Binding and Release of Cations by Sarcoplasmic Reticulum before and after Removal of Lipid |
title_full |
Binding and Release of Cations by Sarcoplasmic Reticulum before and after Removal of Lipid |
title_fullStr |
Binding and Release of Cations by Sarcoplasmic Reticulum before and after Removal of Lipid |
title_full_unstemmed |
Binding and Release of Cations by Sarcoplasmic Reticulum before and after Removal of Lipid |
title_sort |
Binding and Release of Cations by Sarcoplasmic Reticulum before and after Removal of Lipid |
author |
Carvalho, Arsélio P. |
author_facet |
Carvalho, Arsélio P. |
author_role |
author |
dc.contributor.author.fl_str_mv |
Carvalho, Arsélio P. |
description |
The Ca2+ bound actively in the presence of ATP by sarcoplasmic reticulum isolated from rabbit skeletal muscle is released by Zn2+ (or Cd2+) as well as by phospholipases A or C and by trypsin. Zinc ions also release Mg2+ and are taken up passively by the reticulum membranes, whereas phospholipases A and C and trypsin release only the actively bound Ca2+. Phospholipase A, and to a smaller extent phospholipase C and trypsin, increase the passive cation-binding capacity of reticulum. Thus, concurrently with the loss of selectively bound Ca2+ caused by these agents, there is an increase in the passively bound Mg2+. The increase in the passive cation-binding capacity of reticulum induced by phospholipase depends on the presence of the splitting products of phospholipids, since their removal when digested reticulum is washed with a 2.5% albumin solution decreases the binding capacity to about 50% of the original value. When Ca2+, Mg2+ or Sr2+ is bound passively by reticulum, the ratio of H+ released to either of these divalent cations bound, expressed in terms of nequiv H+ released per nequiv divalent cation bound is about 1.0, but when Zn2+ is taken up, the ratio H+/Zn2+ is only about 0.5, which suggests that some of the Zn2+ is bound at sites that do not release H+ or bind Ca2+. After lipid extraction with 90% acetone, the cation-binding capacity and H+ release are decreased to about 40% of the original values. This effect is particularly evident between pH values of about 6.0 and 8.0. The apparent passive Ca2+-binding affinity is not affected by the lipid removal. |
publishDate |
1972 |
dc.date.none.fl_str_mv |
1972 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10316/8347 http://hdl.handle.net/10316/8347 https://doi.org/10.1111/j.1432-1033.1972.tb01865.x |
url |
http://hdl.handle.net/10316/8347 https://doi.org/10.1111/j.1432-1033.1972.tb01865.x |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
European Journal of Biochemistry. 27:3 (1972) 491-502 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
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RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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1799133843177865216 |