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Asymmetric distribution of phospholipids in acetylcholine receptor-rich membranes from T. marmorata electric organ.
Bonini de Romanelli, I C; Aveldaño, M I; Barrantes, F J.
Afiliação
  • Bonini de Romanelli IC; Instituto de Investigaciones Bioquimicas, Universidad Nacional del Sur, Bahia Blanca, Argentina.
Int J Biochem ; 22(7): 785-9, 1990.
Article em En | MEDLINE | ID: mdl-2401378
1. The distribution of phospholipids between the two leaflets of the lipid bilayer in acetylcholine receptor (AChR)-rich membranes from T. marmorata has been examined with two complementary techniques: chemical derivatization with the membrane-impermeable reagent trinitrobenzenesulphonate (TNBS) and B.cereus phospholipase C hydrolysis. 2. AChR-membranes were reacted with TNBS at 0-4 and 37 degrees C and the accessibility of their aminophospholipids was compared to that of rod outer segment and erythrocyte membranes. The results indicate that more of the total ethanolamine glycerophospholipid (EGP) than of the total phosphatidylserine (PS) is located in the outer monolayer. 3. Nearly half the phospholipid content of AChR membranes is hydrolyzed by phospholipase C with a half-time of ca. 1.6 min at 25 degrees C. Consistent with the TNBS results, more of the total EGP than of the total PS is degraded. Beyond 3 min the reaction slows down, relatively smaller additional amounts of lipids are hydrolyzed, and all phospholipid classes are attacked to a similar extent, indicating that after half the lipid is removed all phospholipids become accessible to the enzyme. 4. The results indicate that the outer leaflet of the bilayer is richer in ethanolamine and choline glycerophospholipids, whereas phosphatidylinositol, most of the sphingomyelin, and ca 65% of the PS are located on the inner leaflet.
Assuntos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Ácidos Fosfatídicos / Fosfolipídeos / Torpedo / Receptores Colinérgicos / Órgão Elétrico Limite: Animals Idioma: En Revista: Int J Biochem Ano de publicação: 1990 Tipo de documento: Article País de afiliação: Argentina País de publicação: Reino Unido
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Ácidos Fosfatídicos / Fosfolipídeos / Torpedo / Receptores Colinérgicos / Órgão Elétrico Limite: Animals Idioma: En Revista: Int J Biochem Ano de publicação: 1990 Tipo de documento: Article País de afiliação: Argentina País de publicação: Reino Unido