Chlorophyll breakdown in senescent chloroplasts

The cleavage of pheophorbide (Pheide) a into primary fluorescent chlorophyll (Chl) catabolites (pFCCs) in senescent chloroplasts was investigated. Chloroplast preparations isolated from senescent canola (Brassica napus) cotyledons exhibited light-dependent production of pFCC when assay mixtures were...

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Bibliographic Details
Published in:Plant physiology (Bethesda) 1997-10, Vol.115 (2), p.669-676
Main Authors: Rodoni, S, Muhlecker, W, Anderl, M, Krautler, B, Moser, D, Thomas, H, Matile, P, Hortensteiner, S
Format: Article
Language:English
Subjects:
ACTIVIDAD ENZIMATICA
ACTIVITE ENZYMATIQUE
AVEJENTAMIENTO
BIOCHEMICAL PATHWAYS
BRASSICA NAPUS
CAPSICUM ANNUUM
CATABOLISM
CATABOLISME
CATABOLISMO
CELL MEMBRANES
CHEMICAL REACTIONS
CHEMICAL STRUCTURE
CHLOROPHYLLE
CHLOROPHYLLS
CHLOROPLASTE
CHLOROPLASTS
CLOROFILAS
CLOROPLASTO
COTILEDONES
COTYLEDON
COTYLEDONS
ENZYMIC ACTIVITY
ESTRUCTURA QUIMICA
FERREDOXIN
FLUORESCENCE
FLUORESCENCIA
HORDEUM VULGARE
LIGHT
LUMIERE
LUZ
MEMBRANAS CELULARES
MEMBRANE CELLULAIRE
METABOLITE
METABOLITES
METABOLITOS
METALLOPROTEINE
METALLOPROTEINS
METALPROTEINAS
OXIDOREDUCTASES
OXIDORREDUCTASAS
OXYDOREDUCTASE
OXYGENASES
PHEIDE A OXYGENASE
REACCIONES QUIMICAS
REACTION CHIMIQUE
REGULATION
SENESCENCE
STRUCTURE CHIMIQUE
SUBSTRATES
VIA BIOQUIMICA DEL METABOLISMO
VOIE BIOCHIMIQUE DU METABOLISME
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Description
Summary:The cleavage of pheophorbide (Pheide) a into primary fluorescent chlorophyll (Chl) catabolites (pFCCs) in senescent chloroplasts was investigated. Chloroplast preparations isolated from senescent canola (Brassica napus) cotyledons exhibited light-dependent production of pFCC when assay mixtures were supplemented with ferredoxin (Fd). pFCC production in detergent-solubilized membranes was dependent on the presence of an Fd-reducing system. Pheide a cleavage required the action of two proteins, Pheide a oxygenase and a stroma protein. In the absence of stroma protein, Pheide a oxygenase converted Pheide a into a red Chl catabolite (RCC), the presumptive intermediary product of Pheide a cleavage. Incubation of the stroma protein (RCC reductase) together with chemically synthesized RCC resulted in the production of three different FCCs. Two of these catabolites were identical to the pFCCs from canola or barley (Hordeum vulgare) (pFCC-1) and sweet pepper (Capsicum annuum) (pFCC-2), respectively. Thus, the conversion of Pheide a to pFCC could be demonstrated to proceed in two consecutive steps, and both reactions depended on reduced Fd as the source of electrons. The function of Fd in Chl breakdown in vivo is corroborated by the marked retention of this protein until the late stages of senescence, as demonstrated by immunoblotting
ISSN:0032-0889
1532-2548
DOI:10.1104/pp.115.2.669