Calcium- and calmodulin-regulated breakdown of phospholipid by microsomal membranes from bean cotyledons
Material type:![Article](/opac-tmpl/lib/famfamfam/AR.png)
- Phaseolus vulgaris
- Enzymes
- Fatty acids
- CA
- Metabolism
- Cell structure
- Canada
- COMPOSITION
- Cytology
- FAT CONTENT
- MINERALS AND NUTRIENTS
- North America
- Phaseolus vulgaris
- Enzimas
- Acidos grasos
- CA
- Metabolismo
- ESTRUCTURA DE LA CELULA
- Canadá
- Frijol
- Beans
- Journal articles
- Artículos en revistas
- Electronic documents
- Documentos electrónicos
- Journal article
- 29961
Item type | Current library | Collection | Call number | Copy number | Status | Date due | Barcode | Item holds | |
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CIAT Library Web | Electronic Document | 29961 (Browse shelf(Opens below)) | Not For Loan (Restricted Access) | |||||
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CIAT Library Document collection CINFOS | Document Collection CINFOS | 29961 (Browse shelf(Opens below)) | c.1 | Short Loan | 100052856 |
Se ha tenido evidencia de que el Ca(2+) y la calmodulina estan involucradas en la regulacion de la descomposicion fosfolipida en membranas microsomicas de cotiledones de frijol siguiendo la formacion de productos radiomarcados de la degradacion de (U-(14)C) fosfatidilcolina. Se encontro que 3 enzimas asociadas a la membrana mediaban la descomposicion de (U-(14)C) fosfatidilcolina: la fosfolipasa D, la fosfatasa acida fosfatidica y la hidrolasa acil lipolitica. La fosfolipasa D y la fosfatasa acida fosfatidica fueron ambas estimuladas por los niveles fisiologicos de Ca(2+) libre, mientras que la hidrolasa acilo lipolitica demostro ser insensible al Ca(2+). La fosfolipasa D no fue afectada por la calmodulina, pero la actividad de la fosfatasa acida fosfatidica fue estimulada tambien por los niveles nanomolares de calmodulina en la presencia de 15 micromolares de Ca(2+) libre. El calmidazolio, un antagonista de la calmodulina, inhibio la actividad de la fosfatasa acida fosfatidica a valores IC50 que oscilan entre 10 y 15 micromolares. Por tanto, la estimulacion inducida por Ca(2+) de la fosfatasa acida fosfatidica parece estar mediada por la calmodulina, mientras que el efecto del Ca(2+) en la fosfolipasa D es independiente de la calmodulina. Se discute el papel del Ca(2+) como un segundo mensajero en la iniciacion de la degradacion de los lipidos de la membrana. (RA-CIAT) spa
Evidence for the involvement of Ca(2+) and calmodulin in the regulation of phospholipid breakdown by microsomal membranes from bean cotyledons has been obtained by following the formation of radiolabeled degradation products from (U-(14)C) phosphatidylcholine. Three membrane-associated enzymes were found to mediate the breakdown of (U-(14)C) phosphatidylcholine, namely, phospholipase D, phosphatidic acid phosphatase, and lipolytic acyl hydrolase. Phospholipase D and phosphatidic acid phosphatase were both stimulated by physiological levels of free Ca(2+), whereas lipolytic acyl hydrolase proved to be insensitive to Ca(2+). Phospholipase D was unaffected by calmodulin, but the activity of phosphatidic acid phosphatase was additionally stimulated by nanomolar levels of calmodulin in the presence of 15 micromolar free Ca(2+). Calmidazolium, a calmodulin antagonist, inhibited phosphatidic acid phosphatase activity at IC50 values ranging from 10 to 15 micromolar. Thus, the Ca(2+)-induced stimulation of phosphatidic acid phosphatase appears to be mediated through calmodulin, whereas the effect of Ca(2+) on phospholipase D is independent of calmodulin. The role of Ca(2+) as a 2nd messenger in the initiation of membrane lipid degradation is discussed. (AS) eng