Publication: Cambios en actividad triosa-fosfato isomerasa y estudio de su posible
pérdida por cloroplastos durante el envejecimiento de hojas
Authors
Cuello Moreno, Juan ; Sabater, B. ; Quiles Ródenas, María José de Jesus
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Facultad de Biología
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Publisher
Murcia: Universidad de Murcia, Servicio de Publicaciones
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DOI
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info:eu-repo/semantics/article
Description
Abstract
Hemos estudiado los cambios relativos de triosa-fosfato isomerasa en el citoplasma y en los cloroplastos
durante el envejecimiento de las hojas primarias de cebada. Las fracciones subcelulares se aislaron por
ultracentrifugación hasta equilibrio en un gradiente de densidad de sacarosa.
Las actividades glucosa-6-fosfato deshidrogenasa y TIM del citoplasma disminuyeron a lo largo del
envejecimiento y su pérdida era retrasada por quinetina. La actividad TIM en los cloroplastos era relativamente baja.
La presencia de actividad TIM en fracciones de ultracentrifugación situadas entre las de cloroplastos y
citoplasma sugirió que la actividad TIM era perdida por los cloroplastos rotos. Sin embargo, no encontramos
factor estimulante de la rotura de los cloroplastos en hojas en envejecimiento.
We have studied the relative changes of triose-phosphate isomerase (TIM) in cytoplasm and chloroplasts during the senescence of primary barley leaves. The subcellular fractions were isolated by equillibrium ultracentrifugation in a density sucrose gradient. Cytoplasmic glucose-6-phosphate dehydrogenase and TIM activities diminished during senescence and their loss was retarded by kinetin. TIM activity was relatively low in chloroplasts. The presence of TIM activity between chloroplast and cytoplasm ultracentrifugation fractions suggested that TIM activity was lost from broken chloroplasts. However, we do not find in senescent leaves any factor stimulating chloroplasts breakdown
We have studied the relative changes of triose-phosphate isomerase (TIM) in cytoplasm and chloroplasts during the senescence of primary barley leaves. The subcellular fractions were isolated by equillibrium ultracentrifugation in a density sucrose gradient. Cytoplasmic glucose-6-phosphate dehydrogenase and TIM activities diminished during senescence and their loss was retarded by kinetin. TIM activity was relatively low in chloroplasts. The presence of TIM activity between chloroplast and cytoplasm ultracentrifugation fractions suggested that TIM activity was lost from broken chloroplasts. However, we do not find in senescent leaves any factor stimulating chloroplasts breakdown
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