Lithium-7 NMR relaxation study of lithium binding in human erythrocytes
Autor(a) principal: | |
---|---|
Data de Publicação: | 1993 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10316/10512 https://doi.org/10.1021/bi00212a014 |
Resumo: | We used 7Li NMR spin-lattice (TI) and spin-spin (Tz) relaxation time measurements to investigate the binding of Li+ in human red blood cell (RBC) suspensions. In RBCs containing 1.4 mM Li+, the intracellular 7Li NMR T2 relaxation value (0.30 f 0.03 s) was much smaller than the corresponding TI value (6.0 f 0.1 s), yielding a ratio of TI to T2 of 20. For 1.5 mM LiCl solutions whose viscosities were adjusted to 5 CP with glycerol, the values of the T1/T2 ratios were as follows: 49 for unsealed RBC membrane (2.0 mg of protein/mL); 4.4 for spectrin (1.9 mg/mL); 1.5 for 5.4 mM 2,3-bisphosphoglycerate (BPG); 2.2 for 2.7 mM carbonmonoxyhemoglobin (COHb); 1.6 for 2.0 mM ATP; and 1.2 for a 50/50% (v/v) glycerol-water mixture. Intracellular viscosity and the electric field gradients experienced by Li+ when traversing the spectrin-actin network therefore are not responsible for the large values of the Tl/ T2 ratios observed in Li+-loaded RBCs. We conclude that the RBC membrane is the major Li+ binding site in Li+-loaded RBCs (KI=, 215 f 36 M-l) and that the binding of Li+ to COHb, BPG, spectrin-actin, or ATP is weak. Partially relaxed 7Li NMR spectra of Li+-containing RBC membrane suspensions indicated the presence of two relaxation components, one broad and one narrow. At the same extravesicular Li+ and protein concentrations, the TI values for right-side-out RBC vesicle suspensions were at least 2-fold larger than those for inside-out RBC vesicle suspensions; the inner layer of the RBC membrane, which has a larger percentage of anionic phospholipids than the outer layer, contributes mostly to Li+ binding. |
id |
RCAP_08f8c9dbd25e486b6e264d3bd0f066d7 |
---|---|
oai_identifier_str |
oai:estudogeral.uc.pt:10316/10512 |
network_acronym_str |
RCAP |
network_name_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository_id_str |
7160 |
spelling |
Lithium-7 NMR relaxation study of lithium binding in human erythrocytesWe used 7Li NMR spin-lattice (TI) and spin-spin (Tz) relaxation time measurements to investigate the binding of Li+ in human red blood cell (RBC) suspensions. In RBCs containing 1.4 mM Li+, the intracellular 7Li NMR T2 relaxation value (0.30 f 0.03 s) was much smaller than the corresponding TI value (6.0 f 0.1 s), yielding a ratio of TI to T2 of 20. For 1.5 mM LiCl solutions whose viscosities were adjusted to 5 CP with glycerol, the values of the T1/T2 ratios were as follows: 49 for unsealed RBC membrane (2.0 mg of protein/mL); 4.4 for spectrin (1.9 mg/mL); 1.5 for 5.4 mM 2,3-bisphosphoglycerate (BPG); 2.2 for 2.7 mM carbonmonoxyhemoglobin (COHb); 1.6 for 2.0 mM ATP; and 1.2 for a 50/50% (v/v) glycerol-water mixture. Intracellular viscosity and the electric field gradients experienced by Li+ when traversing the spectrin-actin network therefore are not responsible for the large values of the Tl/ T2 ratios observed in Li+-loaded RBCs. We conclude that the RBC membrane is the major Li+ binding site in Li+-loaded RBCs (KI=, 215 f 36 M-l) and that the binding of Li+ to COHb, BPG, spectrin-actin, or ATP is weak. Partially relaxed 7Li NMR spectra of Li+-containing RBC membrane suspensions indicated the presence of two relaxation components, one broad and one narrow. At the same extravesicular Li+ and protein concentrations, the TI values for right-side-out RBC vesicle suspensions were at least 2-fold larger than those for inside-out RBC vesicle suspensions; the inner layer of the RBC membrane, which has a larger percentage of anionic phospholipids than the outer layer, contributes mostly to Li+ binding.American Chemical Society1993-12info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10316/10512http://hdl.handle.net/10316/10512https://doi.org/10.1021/bi00212a014engBiochemistry. 32:49 (1993) 13490-134980006-2960Rong, QinfenEspanol, MarycelineFreitas, Duarte Mota deGeraldes, Carlos F. G. C.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:RCAAP2020-02-11T18:17:26Zoai:estudogeral.uc.pt:10316/10512Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T20:55:46.878025Repositório 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 |
Lithium-7 NMR relaxation study of lithium binding in human erythrocytes |
title |
Lithium-7 NMR relaxation study of lithium binding in human erythrocytes |
spellingShingle |
Lithium-7 NMR relaxation study of lithium binding in human erythrocytes Rong, Qinfen |
title_short |
Lithium-7 NMR relaxation study of lithium binding in human erythrocytes |
title_full |
Lithium-7 NMR relaxation study of lithium binding in human erythrocytes |
title_fullStr |
Lithium-7 NMR relaxation study of lithium binding in human erythrocytes |
title_full_unstemmed |
Lithium-7 NMR relaxation study of lithium binding in human erythrocytes |
title_sort |
Lithium-7 NMR relaxation study of lithium binding in human erythrocytes |
author |
Rong, Qinfen |
author_facet |
Rong, Qinfen Espanol, Maryceline Freitas, Duarte Mota de Geraldes, Carlos F. G. C. |
author_role |
author |
author2 |
Espanol, Maryceline Freitas, Duarte Mota de Geraldes, Carlos F. G. C. |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Rong, Qinfen Espanol, Maryceline Freitas, Duarte Mota de Geraldes, Carlos F. G. C. |
description |
We used 7Li NMR spin-lattice (TI) and spin-spin (Tz) relaxation time measurements to investigate the binding of Li+ in human red blood cell (RBC) suspensions. In RBCs containing 1.4 mM Li+, the intracellular 7Li NMR T2 relaxation value (0.30 f 0.03 s) was much smaller than the corresponding TI value (6.0 f 0.1 s), yielding a ratio of TI to T2 of 20. For 1.5 mM LiCl solutions whose viscosities were adjusted to 5 CP with glycerol, the values of the T1/T2 ratios were as follows: 49 for unsealed RBC membrane (2.0 mg of protein/mL); 4.4 for spectrin (1.9 mg/mL); 1.5 for 5.4 mM 2,3-bisphosphoglycerate (BPG); 2.2 for 2.7 mM carbonmonoxyhemoglobin (COHb); 1.6 for 2.0 mM ATP; and 1.2 for a 50/50% (v/v) glycerol-water mixture. Intracellular viscosity and the electric field gradients experienced by Li+ when traversing the spectrin-actin network therefore are not responsible for the large values of the Tl/ T2 ratios observed in Li+-loaded RBCs. We conclude that the RBC membrane is the major Li+ binding site in Li+-loaded RBCs (KI=, 215 f 36 M-l) and that the binding of Li+ to COHb, BPG, spectrin-actin, or ATP is weak. Partially relaxed 7Li NMR spectra of Li+-containing RBC membrane suspensions indicated the presence of two relaxation components, one broad and one narrow. At the same extravesicular Li+ and protein concentrations, the TI values for right-side-out RBC vesicle suspensions were at least 2-fold larger than those for inside-out RBC vesicle suspensions; the inner layer of the RBC membrane, which has a larger percentage of anionic phospholipids than the outer layer, contributes mostly to Li+ binding. |
publishDate |
1993 |
dc.date.none.fl_str_mv |
1993-12 |
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/10316/10512 http://hdl.handle.net/10316/10512 https://doi.org/10.1021/bi00212a014 |
url |
http://hdl.handle.net/10316/10512 https://doi.org/10.1021/bi00212a014 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Biochemistry. 32:49 (1993) 13490-13498 0006-2960 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.publisher.none.fl_str_mv |
American Chemical Society |
publisher.none.fl_str_mv |
American Chemical Society |
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 |
instname_str |
Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
instacron_str |
RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
repository.mail.fl_str_mv |
|
_version_ |
1799133843885654016 |