Changes in Succinyl CoA Synthetase Activity in Etiolated Bean Leaves Caused by Illumination

Steer, B. T.; Gibbs, Martin

doi:10.1104/pp.44.5.775

Cited by 8 publications

(3 citation statements)

References 15 publications

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“…Succinyl thiokinase, which forms succinyl-CoA, has been reported to be present in wheat chloroplasts (21), in Jerusalem artichoke mitochondria (23), and in etiolated bean leaf homogenates (31). If succinylCoA, produced in the mitochondrion is used there for ALA formation, then calculations based on respiration data from the lag phase of greening Chlamydomonas (22) and bean leaves (34) indicate that the succinyl-CoA that can be formed from a-ketoglutarate in the citric acid cycle is at least 100 to 1000 times that required for ALA formation.…”

Section: Resultsmentioning

confidence: 99%

Controls on Chlorophyll Synthesis in Barley

1970

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In 7-to 10-day-old leaves of etiolate(I barley (Hordeum vulgare), all of tile eiizymes that convert 1-aminolevulinic acid to chlorophyll are nonlimiting duri-ing the first 6 to 12 hours of illumination, even in the presence of iinhibitors of protein synthesis. The limiting activity for chlorophyll synthesis appears to be a protein (or proteins) related to the synthesis of 6-aminolevulinic acid, prestumably i-aininolevtulinic acid synthetase. Protein Schiff and Epstein (26), and others have suggested that the rate of ALA synthesis is controlled by a negative feedback in which protochlorophyllide or the protochlorophyllide holochrome inhibits the activity of ALA-synthetase. Gassman and Bogorad (5, 6) have proposed the hypothesis that light regulates chlorophyll synthesis in young bean leaves but that synthesis of RNA was required as a precursor step in this process.In this paper we shall present further evidence to support the hypotheses that light stimulates the synthesis of an enzyme which forms 6-aminolevulinic acid, that this is the rate-limiting enzyme in chlorophyll synthesis, and that, at least in barley, RNA synthesis may not be required for early chlorophyll synthesis. METHODS AND MATERIALSBarley (Hordeum vulgare var. Wong; W. A. Burpee Co., Philadelphia, Pa.) seedlings were grown in vermiculite beds in the dark in closed cabinets. The seedlings were watered with tap water every second day. The temperature in the growth room was regulated at 25 i 2 C. The growth rate of the seedlings is shown in Figure 1. The period of most rapid growth was over after 7 days. The first leaf was almost fully formed at this time. A second, smaller leaf appeared after 10 days. Unless noted otherwise, seedlings, 7 to 10 days old, were used.All handling of the seedlings was performed under dim, green safelight (less than 1 ft-c with a filter combination that passed only 540-560 nm of light). The dark-grown seedling "tops" were harvested by cutting them off just above the bed; the lowest inch (approximately the coleoptile region) was discarded in seedlings older than 7 days. Approximately 10 g of seedling tops, prepared as above, were placed in 15-mi beakers containing 6 ml of solution, with the bottom 3 cm of the tops immersed in the solution usually for 2 hr in the dark before illumination. The uptake of solutions was facilitated by gently circulating air around the tops with a small fan (40 cubic feet per min). The solutions in the beakers were replenished to ensure maintenance of turgor of the seedlings throughout the experiment. That a 2-hr dark preincubation permitted adequate uptake of solution by the leaves was shown by the following observations. (a) ALA-fed leaves synthesized enough PCHLD in the dark preincubation period to form more CHL than controls in a subsequent 2-hr period of low intensity illumination; (b) CHX decreased the rate of CHL formation within 1 1 hr after it was fed to the leaves.AU illuminations were performed with 7 ft-c of tungsten light unless otherwise noted. The effect of the slight v...

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Section: Resultsmentioning

confidence: 99%

Controls on Chlorophyll Synthesis in Barley

1970

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“…Growth and illumination conditions are reported fully elsewhere (15). Seeds were germinated in darkness and used on the seventh day.…”

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confidence: 99%

Delta-Aminolevulnic Acid Dehydrase in Greening Bean Leaves

Steer¹,

Gibbs²

1969

Plant Physiol.

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“…The biosynthetic pathway of chlorophyll from A-aminolevuIinic acid has been located within the chloroplast (Carell and Kahn 1964), but information regarding the site of the enzymes involved in the production of succinyl CoA, one of the precursors of A-aminolevulinic acid is more contradictory. Steer and Gibbs (1969) noted a rapid formation of succinyl-CoA synthetase during the greening of etiolated bean leaves and Nandi and Waygood (1965) suggested that this en- Physiol. Plant.,25,197I| zyme was located within the chloroplast.…”

Section: Discussionmentioning

confidence: 99%

The Contribution of Photosynthesis to Chlorophyll Formation in Etiolated Mung Bean Leaves

Dodge

Alexander

Blackwood

1971

Physiologia Plantarum

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Chlorophyll formation in seven day old etiolated mung bean leaves was inhibited by CMU. The inhibition was reversed by feeding sucrose, or by leaving the cotyledons attached to the leaves. Photosynthesis appeared to contribute substrates for further chloroplast development soon after its commencement. When sucrose was fed in the presence of CMU at a range of light intensities, there was a distinct light induced promotion of chlorophyll formation at light intensities of 500–2000 lux. Treatment of the leaves with salicyl‐aldoxime, an inhibitor of cyclic photophosphorylation indicated that this process could play an important part in chloroplast development.

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Changes in Succinyl CoA Synthetase Activity in Etiolated Bean Leaves Caused by Illumination

Cited by 8 publications

References 15 publications

Controls on Chlorophyll Synthesis in Barley

Controls on Chlorophyll Synthesis in Barley

Delta-Aminolevulnic Acid Dehydrase in Greening Bean Leaves

The Contribution of Photosynthesis to Chlorophyll Formation in Etiolated Mung Bean Leaves

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