Tocopherol and plastoquinone synthesis in spinach chloroplasts subfractions

Soll, J√orgen; Kemmerling, Monika; Schultz, Gernot

doi:10.1016/0003-9861(80)90066-1

Cited by 133 publications

(84 citation statements)

References 13 publications

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“…The plastidic shikimate pathway (Bickel oral. 1978) is thought to act in the stroma, whereas the synthesis of the prenylquinones ~-tocopherol and plastoquinone could exclusively be demonstrated in the membranes, especially the envelope (Soll et al 1980). The homogentisate has to be transferred from the stroma to the membranes.…”

Section: Discussionmentioning

confidence: 99%

“…No ribolose-l,5-bis-phosphate carboxylase activity could be detected in the envelope fraction (assay according to McNeil et al 1981 ; data not shown). A contamination of thylakoids by envelope was not likely, because the homogentisate-phytyldiphosphate-transferase localized only in the envelope (Soll et al 1980) was not detectable. Rate of homogentisate formation in dependence on substrate concentration.…”

Section: Localisation Of L-amino Acid Oxidase In Chloroplastsmentioning

confidence: 99%

“…Envelope membranes are able to catalyze the enzymatic prenylation of homogentisate with phytyldiphosphate to give 2-methyl-6-phytylquinol (Soll et al 1980) as the first intermediate in the e-tocopherol synthesis. The incorporation of 4-hydroxyphenylpyruvate into 2-methyl-6-phytylquinol by envelope membranes could be shown according to the following two-step reaction:…”

Section: Specific Activity Of Chloroplast Subfractions In Homogentisamentioning

confidence: 99%

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The formation of homogentisate in the biosynthesis of tocopherol and plastoquinone in spinach chloroplasts

Fiedler

Soll

Schultz

1982

Planta

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Abstract.Homogentisate is the precursor in the biosynthesis of ~-tocopherol and plastoquinone-9 in chloroplasts. It is formed of 4-hydroxyphenylpyruvate of the shikimate pathway by the 4-hydroxyphenylpyruvate dioxygenase. In experiments with spinach the dioxygenase was shown to be localized predominatedly in the chloroplasts. Envelope membranes exhibit the highest specific activity, however, because of the high stromal portion of chloroplasts, 60-80% of the total activity is housed in the stroma. The incorporation of 4-hydroxyphenylpyruvate into 2-methyl-6-phytylquinol as the first intermediate in the tocopherol synthesis by the two-step-reaction: 4-Hydroxyphenylpyruvate ~ Homogentisate Phytyl-PP 2-Methyl-6-phytylquinol was demonstrated by using envelope membranes. Homogentisate originates directly from 4-hydroxyphenylpyruvate of the shikimate pathway. Additionally, a bypass exists in chloroplasts which forms 4-hydroxyphenylpyruvate from tyrosine by an L-amino-acid oxidase of the thylakoids and in peroxisomes by a transaminase reaction. Former results about the dioxygenase in peroxisomes were verified.

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Section: Discussionmentioning

confidence: 99%

Section: Localisation Of L-amino Acid Oxidase In Chloroplastsmentioning

confidence: 99%

Section: Specific Activity Of Chloroplast Subfractions In Homogentisamentioning

confidence: 99%

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The formation of homogentisate in the biosynthesis of tocopherol and plastoquinone in spinach chloroplasts

Fiedler

Soll

Schultz

1982

Planta

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“…In dicots like soybean and pinto beans, an initial increase in α-tocopherol levels seen at the onset of germination was found to be followed by a decline [23,32]. Immature chloroplasts isolated from 2-week-old Spinacia oleracea L. seedlings demonstrate a high tocopherol biosynthetic potential [29]. Tocopherol concentrations in older seedlings do not rise any further, presumably due to a combination of lower de novo synthesis and regeneration by, for instance, ascorbate [12,18].…”

Section: Introductionmentioning

confidence: 99%

Accumulation of tocopherols and tocotrienols during seed development of grape (Vitis vinifera L. cv. Albert Lavallée)

Horváth

Wessjohann

Bigirimana

et al. 2006

Plant Physiology and Biochemistry

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Tocopherols and tocotrienols are present in mature seeds. Yet, little is known about the physiological role and the metabolism of these compounds during seed development. Here we present data on tocopherol and tocotrienol accumulation during seed development in Vitis vinifera L. cv. Albert Lavallée (Royal). This species was chosen for its ability to synthesize both tocopherols and tocotrienols. It is shown here for the first time that during seed development there are significant differences in localization and accumulation kinetics of tocopherols and tocotrienols. Tocopherols are found homogeneously dispersed throughout all tissues of the seed, in concentrations ranging from 20 to 100 μg tocopherol per g dry weight. Tocopherol levels decrease gradually during seed development. In contrast, tocotrienols are only found in the endosperm of the seeds, accumulating in a sigmoid fashion during the maturation period of seed development. Tocotrienol levels were found to be (54 ± 7.4) μg/g dry seed in 90-day-old seeds of V. vinifera L. Furthermore, tocotrienol biosynthesis is demonstrated in these seeds during tocotrienol accumulation and in an endosperm fraction isolated at 75 days after flowering.

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“…The majority of the chloroplast enzymes implicated in the biosynthesis of prenylquinones have been localized at the inner membrane of the chloroplast envelope [13][14][15], with the exception of part of the phylloquinone biosyn-thetic pathway that is compartmentalized in peroxisomes [16,17] (Figure 1). …”

Section: Introductionmentioning

confidence: 99%

Unexpected roles of plastoglobules (plastid lipid droplets) in vitamin K 1 and E metabolism

Spicher

Kessler

2015

Current Opinion in Plant Biology

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Tocopherol (vitamin E) and phylloquinone (vitamin K 1 ) are lipid-soluble antioxidants that can only be synthesized by photosynthetic organisms. These compounds function primarily at the thylakoid membrane but are also present in chloroplast lipid droplets, also known as plastoglobules (PG). Depending on environmental conditions and stage of plant development, changes in the content, number and size of PG occur. PG are directly connected to the thylakoid membrane via the outer lipid leaflet. Apart from storage, PG are active in metabolism and likely trafficking of diverse lipid species. This review presents recent advances on how plastoglobules are implicated in the biosynthesis and metabolism of vitamin E and K.

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Tocopherol and plastoquinone synthesis in spinach chloroplasts subfractions

Cited by 133 publications

References 13 publications

The formation of homogentisate in the biosynthesis of tocopherol and plastoquinone in spinach chloroplasts

The formation of homogentisate in the biosynthesis of tocopherol and plastoquinone in spinach chloroplasts

Accumulation of tocopherols and tocotrienols during seed development of grape (Vitis vinifera L. cv. Albert Lavallée)

Unexpected roles of plastoglobules (plastid lipid droplets) in vitamin K 1 and E metabolism

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