Glyoxylate carboxy-lyase activity in the unicellular green alga gloemonas SP.

Badour, S. S.; Waygood, E. R.

doi:10.1016/0005-2744(71)90242-7

Cited by 14 publications

(6 citation statements)

References 19 publications

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“…Harrop and Kornberg (12) suggested that the presence of isocitrate lyase in autotrophic green algae would not necessarily implicate the operation of glyoxylate cycle to replenish the C4 acids as in algae or bacteria grown on acetate (14), since these acids could arise by the /8-carboxylation of phosphoenolpyruvate. This was supported further by the reports of Foo et al (7) and Badour and Waygood (2).…”

supporting

confidence: 78%

“…Isocitrate has been demonstrated in crude extracts of various unicellular algae when forced to grow on acetate as the sole carbon source (10,11). However, substantial activity has been observed in photoautotrophically grown algae with CO2 as the sole carbon source (2,3,7,12,27). Harrop and Kornberg (12) suggested that the presence of isocitrate lyase in autotrophic green algae would not necessarily implicate the operation of glyoxylate cycle to replenish the C4 acids as in algae or bacteria grown on acetate (14), since these acids could arise by the /8-carboxylation of phosphoenolpyruvate.…”

mentioning

confidence: 99%

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Isocitrate Lyase in Green Leaves

Godavari¹,

Badour²,

Waygood³

1973

Plant Physiol.

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supporting

confidence: 78%

mentioning

confidence: 99%

Isocitrate Lyase in Green Leaves

Godavari¹,

Badour²,

Waygood³

1973

Plant Physiol.

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“…Glyoxylate carboligase (EC 4.1.1.47) was assayed by measuring the J4CO2 produced from [1J4C]glyoxylate. Formation of tartronic-acid semialdehyde during the reaction was tested by thin-layer chromatography (Badour and Waygood 1971). Chlorophyll was measured according to B6ger (1964).…”

Section: Methodsmentioning

confidence: 99%

Isolation and characterization of peroxisomes from diatoms

Winkler

Stabenau

1995

Planta

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Abstract. Peroxisomes were isolated by gradient centrifugation from two different diatoms: Nitzschia laevis (subgroup of Pennales) and Thalassiosirafluviatilis (subgroup of Centrales). In neither of these organelles could catalase or any H202-forming oxidase be demonstrated. The glycolate-oxidizing enzyme present in the peroxisomes is a dehydrogenase capable of oxidizing L-lactate as well. The peroxisomes also contain the glyoxysomal markers isocitrate lyase and malate synthase. However, enzymes of the fatty-acid [3-oxidation pathway are located exclusively in the mitochondria. The mitochondria additionally possess glutamate-glyoxylate aminotransferase and a glycolate dehydrogenase which differs from the peroxisomal glycolate dehydrogenase since it preferably utilizes o-lactate as an alternative substrate. Hydroxypyruvate reductase and glyoxylate carboligase were not found in the cells of either diatom. By culturing Nitzschia laevis it could be demonstrated that decreasing the CO 2 concentration in the aeration mixture from 2% to 0.03% and increasing the irradiance from 40 to 250 pmol quanta.m -2. s -1 resulted in an increase of all peroxisomal enzyme activities. In addition, enzyme activities of the [3-oxidation pathway were increased. However, mitochondrial glycolate dehydrogenase and aminotransferase did not alter their activities under these conditions. Summarizing all results, it is postulated that there are two different pathways for the metabolism of glycolate in the diatoms.

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Section: Introductionmentioning

confidence: 99%

“…They also excrete large amounts of glycolate (4, 7, 35). However, photorespira-I tion appears to be suppressed and glycolate excretion is negligible if the cells are grown under air-levels of 02 and C02 (3,4,14,25).It is thought that algae grown under air-levels of C02 actively pump in dissolved inorganic carbon, raising the intracellular level of inorganic carbon (2). This would presumably suppress the oxygenase function ofribulose bisphosphate carboxylase/oxygenase, thus lowering the rate of glycolate synthesis.…”

mentioning

confidence: 99%

Glycolate Metabolism in Low and High CO₂-Grown Chlorella pyrenoidosa and Pavlova lutheri as Determined by ¹⁸O-Labeling

Veau

Burris²

1989

Plant Physiol.

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Photorespiration in Chlorella pyrenoidosa Chick. was assayed by measuring '10-labeled intermediates of the glycolate pathway.Glycolate, glycine, serine, and excreted glycolate were isolated and analyzed on a gas chromatograph/mass spectrometer to determine isotopic enrichment. Rates of glycolate synthesis were determined from 180-labeling kinetics of the intermediates, pool sizes, derived rate equations, and nonlinear regression techniques. Glycolate synthesis was higher in high C02-grown cells than in air-grown cells when both were assayed under the same 02 and CO2 concentrations. Synthesis of glycolate, for both types of cells, was sfimulated by high 02 levels and inhibited by high CO2 levels. Glycolate synthesis in 1.5% C02-grown Chlorella, when exposed to a 0.035% CO2 atmosphere, increased from about 41 to 86 nanomoles per milligram chlorophyll per minute when the 02 concentration was increased from 21% to 40%. Glycolate synthesis in air-grown cells increased from 2 to 6 nanomoles per milligram chlorophyll per minute under the same gas levels. Synthesis was undetectable when either the 02 concentration was lowered to 2% or the CO2 concentration was raised to 1.5%. Glycolate excretion was also sensitive to 02 and CO2 concentrations in 1.5% C02-grown cells and the glycolate that was excreted was '10-labeled. Air-grown cells did not excrete glycolate under any experimental condition. Indirect evidence indicated that glycolate may be excreted as a lactone in Chlorella.Photorespiratory 18O-labeling kinetics were determined for Pavlova Iutheri, which unlike Chlorella and higher plants did not directly synthesize glycine and serine from glycolate. This alga did excrete a significant proportion of newly synthesized glycolate into the media.The existence and the amount of photorespiration in freshwater algae is uncertain (8 to photorespire when transferred to low C02 levels and to do so in a manner similar to terrestrial C3 plants (33). They have high C02 compensation points (14), evolve large amounts of C02 into C02-free air during illumination (14), and are photosynthetically inhibited by 21%°02(18, 25). They also excrete large amounts of glycolate (4, 7, 35). However, photorespira-I tion appears to be suppressed and glycolate excretion is negligible if the cells are grown under air-levels of 02 and C02 (3,4,14,25).It is thought that algae grown under air-levels of C02 actively pump in dissolved inorganic carbon, raising the intracellular level of inorganic carbon (2). This would presumably suppress the oxygenase function ofribulose bisphosphate carboxylase/oxygenase, thus lowering the rate of glycolate synthesis. However, it is not entirely clear ifglycolate synthesis is completely suppressed. It has been reported that if cells are treated with a glycolate metabolism inhibitor they excrete almost as much glycolate as if they had been grown under elevated C02 (31).The main objective of our research was to quantify and then compare the photorespiratory rate ofair-grown and 1.5% C02-in-air-grown Chlorella pyr...

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Glyoxylate carboxy-lyase activity in the unicellular green alga gloemonas SP.

Cited by 14 publications

References 19 publications

Isocitrate Lyase in Green Leaves

Isocitrate Lyase in Green Leaves

Isolation and characterization of peroxisomes from diatoms

Glycolate Metabolism in Low and High CO₂-Grown Chlorella pyrenoidosa and Pavlova lutheri as Determined by ¹⁸O-Labeling

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Glyoxylate carboxy-lyase activity in the unicellular green alga gloemonas SP.

Cited by 14 publications

References 19 publications

Isocitrate Lyase in Green Leaves

Isocitrate Lyase in Green Leaves

Isolation and characterization of peroxisomes from diatoms

Glycolate Metabolism in Low and High CO2-Grown Chlorella pyrenoidosa and Pavlova lutheri as Determined by 18O-Labeling

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Glycolate Metabolism in Low and High CO₂-Grown Chlorella pyrenoidosa and Pavlova lutheri as Determined by ¹⁸O-Labeling