The base-exchange enzyme activities of sarcolemma and sarcoplasmic reticulum from rat heart.
Biochim Biophys Acta
; 835(3): 542-8, 1985 Jul 31.
Article
em En
| MEDLINE
| ID: mdl-2990564
ABSTRACT
The Ca2+ dependent incorporation of [14C]ethanolamine, L-[14C]serine and [14C]choline into phosphatidylethanolamine, phosphatidylserine and phosphatidylcholine, respectively, were investigated in membrane preparations from rat heart. The ethanolamine and serine base-exchange enzyme-catalyzed reactions were associated with the sarcolemma and sarcoplasmic reticulum. There was a 17.2-fold and 6.8-fold enrichment, respectively, of the serine and the ethanolamine base-exchange enzyme activities in the sarcolemma compared to the starting whole homogenate. The sarcoplasmic reticulum was enriched in the ethanolamine and serine base-exchange enzyme activities. The choline base-exchange enzyme activity of all membranes fractions was negligible compared to the ethanolamine or serine base-exchange enzyme activities. The apparent Km for the ethanolamine and serine base-exchange enzyme in sarcolemma was 14 microM and 25 microM, respectively. The pH optimum for these base-exchange activities was 7.5-8.0. There was a dependence upon Ca2+ for these reactions with a 1 or 4 mM concentration required for maximal activity. The properties of the sarcoplasmic reticulum base-exchange enzymes were similar to the sarcolemmal base-exchange enzymes.
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Base de dados:
MEDLINE
Assunto principal:
Sarcolema
/
Retículo Sarcoplasmático
/
Transferases
/
Transferases de Grupos Nitrogenados
/
Miocárdio
Limite:
Animals
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1985
Tipo de documento:
Article