Distinctive properties of the purified Na-Ca exchanger from rod outer segments.
Ann N Y Acad Sci
; 639: 222-33, 1991.
Article
em En
| MEDLINE
| ID: mdl-1785848
ABSTRACT
The Na-Ca exchanger of rod outer segments plays an important role in the regulation of Ca levels in photoreceptor cells. While this transporter shares functional properties with other Na-Ca exchangers, it has several unique features. The purified ROS exchanger migrates as a single band at 220 kDa in SDS-polyacrylamide gels, indicating that the unit size of its polypeptide is larger than other known Na-Ca exchangers (and most transporters). A specific antiserum to the ROS exchanger does not bind to the Na-Ca exchangers found in sarcolemmal vesicles or brain synaptic plasma membranes. Similarly, polyclonal antiserum specific for the cardiac exchanger does not react with ROS or brain proteins. The ROS exchanger requires K for transport activity. By incorporating the purified exchanger into proteoliposomes and measuring the sequestration of K, the actual transport of K is demonstrated. A stoichiometry of 4Na1Ca,1K for the exchanger of ROS has been measured.
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Base de dados:
MEDLINE
Assunto principal:
Segmento Externo da Célula Bastonete
/
Sódio
/
Proteínas de Transporte
/
Cálcio
Limite:
Animals
Idioma:
En
Ano de publicação:
1991
Tipo de documento:
Article