Autolysis of chlorophyll in aqueous and detergent suspensions of chloroplast fragments

High-pressure liquid chromatography was used to separate chlorophyll derivatives in acetone extracts from senescing Citrus fruit peel, autumnal Melia azedarach L. leaves, and dark-held detached parsley (Petroselinum sativum L.) leaves. Chlorophyllide a and another polar, dephytylated derivative accumulated in large amounts in senescing Citrus peel, particularly in fruit treated with ethylene. Ethylene also induced a 4-fold increase in the specific activity of Citrus chlorophyllase (chlorophyll chlorophyllidohydrolase, EC 3.1.1.14). Detailed kinetics based on a hexane/acetone solvent partition system showed that the in vivo increase in dephytylated derivatives coincided with the decrease in total chlorophyll. Polar, dephytylated derivatives accumulated also in senescing Melia leaves. Senescing parsley leaves revealed a very different picture. The gradual disappearance of chlorophyll a was accompanied by an increase in pheophytin a and by the transient appearance of several phytylated derivatives. Only pheophytin a and an adjacent peak were left when all the chlorophyll a had disappeared. The pathways for breakdown of chlorophyll in the Citrus and parsley senescence systems are discussed.

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“…Autolysis of chlorophyll in chloroplast fragments in vitro also suggested differences between the Citrus and parsley systems (40 …”

Section: Discussionmentioning

confidence: 96%

Chlorophyll catabolism in senescing plant tissues: In vivo breakdown intermediates suggest different degradative pathways for Citrus fruit and parsley leaves

Amir-Shapira

Goldschmidt

Altman

1987

Proc. Natl. Acad. Sci. U.S.A.

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182

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“…To address this, we performed in vitro activity assays using chromoplasts of wild-type and RNAi lines at the breaker + 2 d stage, thereby comparing pheophytin-specific activities in solubilized and nonsolubilized chromoplast membranes. For different plant species, including citrus fruits, membrane solubilization has been shown to be a prerequisite for the activation of CLHs (and possibly other dephytylating activities), which are present in membranes in a latent form (Amir-Shapira et al, 1986;Matile et al, 1999). Dephytylation of pheophytin was significantly reduced by about 25% in nonsolubilized chromoplasts of SlPPHi_17 and SlPPHi_27 when compared with the wild type (Fig.…”

Section: Slpph Is Active During Fruit Ripening But Other Unknown Hydmentioning

confidence: 94%

Different Mechanisms Are Responsible for Chlorophyll Dephytylation during Fruit Ripening and Leaf Senescence in Tomato

et al. 2014

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Chlorophyll breakdown occurs in different green plant tissues (e.g. during leaf senescence and in ripening fruits). For different plant species, the PHEOPHORBIDE A OXYGENASE (PAO)/phyllobilin pathway has been described to be the major chlorophyll catabolic pathway. In this pathway, pheophorbide (i.e. magnesium-and phytol-free chlorophyll) occurs as a core intermediate. Most of the enzymes involved in the PAO/phyllobilin pathway are known; however, the mechanism of dephytylation remains uncertain. During Arabidopsis (Arabidopsis thaliana) leaf senescence, phytol hydrolysis is catalyzed by PHEOPHYTINASE (PPH), which is specific for pheophytin (i.e. magnesium-free chlorophyll). By contrast, in fruits of different Citrus spp., chlorophyllase, hydrolyzing phytol from chlorophyll, was shown to be active. Here, we enlighten the process of chlorophyll breakdown in tomato (Solanum lycopersicum), both in leaves and fruits. We demonstrate the activity of the PAO/phyllobilin pathway and identify tomato PPH (SlPPH), which, like its Arabidopsis ortholog, was specifically active on pheophytin. SlPPH localized to chloroplasts and was transcriptionally up-regulated during leaf senescence and fruit ripening. SlPPH-silencing tomato lines were impaired in chlorophyll breakdown and accumulated pheophytin during leaf senescence. However, although pheophytin transiently accumulated in ripening fruits of SlPPH-silencing lines, ultimately these fruits were able to degrade chlorophyll like the wild type. We conclude that PPH is the core phytol-hydrolytic enzyme during leaf senescence in different plant species; however, fruit ripening involves other hydrolases, which are active in parallel to PPH or are the core hydrolases in fruits. These hydrolases remain unidentified, and we discuss the question of whether chlorophyllases might be involved.

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“…Many of these conserved residues were located in the NH 2 -terminal half, suggesting that the functionally and/or structurally important regions might be located in this region. A conserved region in WSCP, 39 PFCPLGI 45 (indicated by the thin bar in Fig. 2), showed homology to the sequence motif called the (F/Y)DPLGL motif (25) of light-harvesting Chl a/b-binding protein and its related proteins, e.g.…”

Section: Sequence Comparisons Of Wscp To Its Homologs In Brassi-mentioning

confidence: 99%

“…44), as well as drought stress, may cause Chl degradation. Although chlorophyllase, the enzyme catalyzing the first step of the Chl degradation, is present in chloroplasts, its activity is latent and observed only after detergent (45) or organic solvent treatments (9). Recently, it has been shown that chlorophyllase activity occurs on the inner chloroplastic envelope (23).…”

Section: Sequence Comparisons Of Wscp To Its Homologs In Brassi-mentioning

confidence: 99%

Molecular Cloning and Functional Expression of a Water-soluble Chlorophyll Protein, a Putative Carrier of Chlorophyll Molecules in Cauliflower

Satoh

Nakayama

Okada

1998

Journal of Biological Chemistry

127

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Autolysis of chlorophyll in aqueous and detergent suspensions of chloroplast fragments

Cited by 34 publications

References 14 publications

Chlorophyll catabolism in senescing plant tissues: In vivo breakdown intermediates suggest different degradative pathways for Citrus fruit and parsley leaves

Chlorophyll catabolism in senescing plant tissues: In vivo breakdown intermediates suggest different degradative pathways for Citrus fruit and parsley leaves

Different Mechanisms Are Responsible for Chlorophyll Dephytylation during Fruit Ripening and Leaf Senescence in Tomato

Molecular Cloning and Functional Expression of a Water-soluble Chlorophyll Protein, a Putative Carrier of Chlorophyll Molecules in Cauliflower

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