Ascorbate Biosynthesis in Mitochondria Is Linked to the Electron Transport Chain between Complexes III and IV

Ascorbic acid is synthesized from galactono-γ-lactone (GL) in plant tissues. An improved extraction procedure involving ammonium sulfate precipitation of membrane proteins from crude leaf homogenates yielded a simple, quick method for determining tissue activities of galactono-γ-lactone dehydrogenas...

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Autores principales: Bartoli, Carlos Guillermo, Pastori, Gabriela M., Foyer, Christine H.
Formato: Articulo
Lenguaje:Inglés
Publicado: 2000
Materias:
Botánica
Ascorbate biosynthesis
Mitochondria
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/123635
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-123635
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Botánica
Ascorbate biosynthesis
Mitochondria
spellingShingle Botánica
Ascorbate biosynthesis
Mitochondria
Bartoli, Carlos Guillermo
Pastori, Gabriela M.
Foyer, Christine H.
Ascorbate Biosynthesis in Mitochondria Is Linked to the Electron Transport Chain between Complexes III and IV
topic_facet Botánica
Ascorbate biosynthesis
Mitochondria
description Ascorbic acid is synthesized from galactono-γ-lactone (GL) in plant tissues. An improved extraction procedure involving ammonium sulfate precipitation of membrane proteins from crude leaf homogenates yielded a simple, quick method for determining tissue activities of galactono-γ-lactone dehydrogenase (GLDH). Total foliar ascorbate and GLDH activity decreased with leaf age. Subcellular fractionation experiments using marker enzymes demonstrated that 80% of the total GLDH activity was located on the inner mitochondrial membrane, and 20% in the microsomal fraction. Specific antibody raised against potato (Solanum tuberosum L.) tuber GLDH recognized a 56-kD polypeptide in extracts from the mitochondrial membranes but failed to detect the equivalent polypeptide in microsomes. We demonstrate that isolated intact mitochondria synthesize ascorbate in the presence of GL. GL stimulated mitochondrial electron transport rates. The respiration inhibitor antimycin A stimulated ascorbate biosynthesis, while cyanide inhibited both respiration and ascorbate production. GL-dependent oxygen uptake was observed in isolated intact mitochondria. This evidence suggests that GLDH delivers electrons to the mitochondrial electron transport chain between complexes III and IV.
format Articulo
Articulo
author Bartoli, Carlos Guillermo
Pastori, Gabriela M.
Foyer, Christine H.
author_facet Bartoli, Carlos Guillermo
Pastori, Gabriela M.
Foyer, Christine H.
author_sort Bartoli, Carlos Guillermo
title Ascorbate Biosynthesis in Mitochondria Is Linked to the Electron Transport Chain between Complexes III and IV
title_short Ascorbate Biosynthesis in Mitochondria Is Linked to the Electron Transport Chain between Complexes III and IV
title_full Ascorbate Biosynthesis in Mitochondria Is Linked to the Electron Transport Chain between Complexes III and IV
title_fullStr Ascorbate Biosynthesis in Mitochondria Is Linked to the Electron Transport Chain between Complexes III and IV
title_full_unstemmed Ascorbate Biosynthesis in Mitochondria Is Linked to the Electron Transport Chain between Complexes III and IV
title_sort ascorbate biosynthesis in mitochondria is linked to the electron transport chain between complexes iii and iv
publishDate 2000
url http://sedici.unlp.edu.ar/handle/10915/123635
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AT pastorigabrielam ascorbatebiosynthesisinmitochondriaislinkedtotheelectrontransportchainbetweencomplexesiiiandiv
AT foyerchristineh ascorbatebiosynthesisinmitochondriaislinkedtotheelectrontransportchainbetweencomplexesiiiandiv
bdutipo_str Repositorios
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