Transbilayer distribution of lipids in a population of sarcoplasmic-reticulum vesicles sealed with their cytoplasmic side outwards.
Biochem J
; 195(1): 287-95, 1981 Apr 01.
Article
em En
| MEDLINE
| ID: mdl-7306055
ABSTRACT
A population of sarcoplasmic-reticulum vesicles, all of which were sealed with their cytoplasmic side outwards, was obtained by density-gradient centrifugation after loading the vesicles with calcium oxalate. The calcium oxalate could subsequently be removed from the vesicles by the reverse action of the calcium-transport system. Measurements of the catalysed exchange of the phosphatidylcholine in the sarcoplasmic-reticulum cytoplasmic monolayer with an exogenous phosphatidylcholine pool suggested that phosphatidylcholine is symmetrically distributed across the sarcoplasmic-reticulum membrane. A similar result was obtained for phosphatidylethanolamine when sarcoplasmic-reticulum lipids were labelled with trinitrobenzenesulphonic acid. Further catalysed lipid-exchange reactions showed that the transverse movement of phosphatidylcholine across the membrane was exceedingly slow (t 1/2 greater than 15 days).
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Retículo Sarcoplasmático
/
Bicamadas Lipídicas
Limite:
Animals
Idioma:
En
Revista:
Biochem J
Ano de publicação:
1981
Tipo de documento:
Article