Role of Aldolase in Photosynthesis. II Demonstration of Aldolase Types in Photosynthetic Organisms

Willard, James M.; Gibbs, Martin

doi:10.1104/pp.43.5.793

Cited by 42 publications

(17 citation statements)

References 14 publications

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“…The proplastids contain a unique complement of hexose-P isomerase, aldolase, and 6-P-gluconate dehydrogenase isoenzymes. Unique isoenzyme of these enzymes are also found in chloroplasts (4,12,(13)(14)(15)18). It is assumed that these multiple enzyme forms are true isoenzymes; however, the possibility exists that they are only different polymeric forms of identical subunits.…”

Section: Discussionmentioning

confidence: 99%

“…These enzymes: hexose-P isomerase, aldolase, and 6-P-gluconate dehydrogenase have all previously been shown to occur as isoenzymes in other higher plant systems (5,12,(14)(15)(16)18). A more detailed physical and kinetic characterization of the 6-P-gluconate dehydrogenase isoenzymes will be presented in a later report.…”

mentioning

confidence: 88%

“…The sole incorporation of one isoenzyme form into the organelle would regulate the subcellular distribution. In fact, when enzyme activities are present in both plastids and the cytosol, isoenzymes are usually found (1-3, 5, 9, [14][15][16]18).…”

mentioning

confidence: 99%

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Isoenzymes of the Glycolytic and Pentose Phosphate Pathways in Proplastids from the Developing Endosperm of Ricinis communis L.

Simcox¹,

Dennis²

1978

Plant Physiol.

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Two isoenzymes each of hexose-P isomerase, aldolase and 6-P-gluconate dehydrogenase have been found in the endosperm of developing castor beans (Ricinus conununis L.). One isoenzyme for each activity is present in the proplastid fraction. Only one form of glucose-6P dehydrogenase was found. It is suggested that the partition of an enzyme activity between cytosol and plastid is regulated by the synthesis of isoenzymes which are subcellular site specific. In addition, this report describes the use of diethylaminoethyl-Sephadex A-25 sievorptive chromatography for the preparation of plant enzymes.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 88%

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Isoenzymes of the Glycolytic and Pentose Phosphate Pathways in Proplastids from the Developing Endosperm of Ricinis communis L.

Simcox¹,

Dennis²

1978

Plant Physiol.

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“…Electron micrographs were taken with a Philip EM 300. using standard methods. Fructose-1,6-bisphosphate D-glyceraldehyde-3-phosphate-lyase (FBP aldolase, EC 4.1.2.13) activity was measured after preincubation at 37°C during 10 min in the presence of Fe 2+ and cysteine [ 16]. The cleavage of FBP was followed at 30°C in 1 ml containing 50 #mol Tris-maleate buffer (pH 7.5), 0.12/Jmol NADH, 4.5 U triosephosphate isomerase, 0.36 U c~-glycerolphosphate dehydrogenase.…”

Section: Isolation Of Carboxysomesmentioning

confidence: 99%

Carboxysomes:‘calvinosomes’?

Beudeker

Kuenen

1981

FEBS Letters

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“…Since in green plants chloroplast and cytoplasmic aldolases might also be expected to have opposing functions, it seemed of interest to compare the properties of the plant aldolases. Although spinach whole leaf (8, 14) and chloroplast (7) aldolases and a pea seed aldolase (10,19,20) had been studied prior to the present investigation, no higher plant aldolase known to be cytoplasmic had been characterized. The purpose of the experiments reported here was to characterize the pea leaf chloroplast and cytoplasmic aldolases and to compare the physical and kinetic properties of the isoenzymes.…”

Section: Introductionmentioning

confidence: 99%

Chloroplast and Cytoplasmic Enzymes

Anderson

Pacold

1972

Plant Physiol.

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Several peaks of aldolase activity are found in the isoelectric focusing pattern of pea (Pisum sativum) leaf chloroplast extracts. One peak, separated by 0.5 pH unit from the major chloroplast aldolase peak, is found when cytoplasmic extracts are focused. The chloroplast and cytoplasmic enzymes have a pH 7.4 optimum with fructose 1,6-diphosphate. In mammalian systems fructose-1,6-diP aldolases from different tissues have kinetic properties related to the function (synthetic or degradative) of the enzyme. Differences in the ratio V.a. fructose-1,6-diP cleavage to Vma. fructose-1,6-diP synthesis led Rutter and coworkers (15) to conclude that muscle aldolase is "more effective in cleaving fructose-1 ,6-diP whereas liver aldolase is relatively more effective in synthesis." Since in green plants chloroplast and cytoplasmic aldolases might also be expected to have opposing functions, it seemed of interest to compare the properties of the plant aldolases. Although spinach whole leaf (8, 14) and chloroplast (7) aldolases and a pea seed aldolase (10,19,20) had been studied prior to the present investigation, no higher plant aldolase known to be cytoplasmic had been characterized. The purpose of the experiments reported here was to characterize the pea leaf chloroplast and cytoplasmic aldolases and to compare the physical and kinetic properties of the isoenzymes.The results indicate that the chloroplast and cytoplasmic aldolases are exceedingly similar enzymes, the pH optima and Michaelis constants for fructose-1 ,6-diP, fructose-1-P, and sedoheptulose-1,7-diP being almost identical. Isoelectric Focusing. Chloroplast and cytoplasmic extracts, prepared as described previously (5) (except that the chloroplast extract was centrifuged 45 min at 500,000g), and containing 10 to 15 mg of protein, were subjected to electrophoresis for 1.5 days in pH 3 to 6 ampholytes at 450 v or pH 4 to 6 ampholytes at 500 v, in a 100-ml LKB isoelectric focusing column at 10 C. Ampholyte and electrode solutions were made up with 5 mm 2-mercaptoethanol. The anode solution (made with 0.5 N H2SO4) was at the bottom of the column. The cathode solution was 0.25 N NaOH. The density gradient was usually made with sucrose. Sorbitol was used in place of sucrose in experiments where aldolase activity was measured as fructose-1,6-diP formation. Fractions (9 drops, 0.7 ml) were collected and analyzed for enzyme activity. The pH of the individual fractions was measured at 0 C using a Radiometer pH meter 26.Purification of Chloroplast and Cytoplasmic Aldolases. Chloroplast and cytoplasmic extracts were prepared as described previously (5) except that the procedure was scaled up for 1 kg of tissue, and the entire shoot of the plant was used. Chloroplasts were usually prepared beforehand and stored at -20 C. The method of Fluri et al. (8) for purification of spinach aldolase was followed, with some modifications. The chloroplast extract, in 10 mm potassium phosphate buffer, pH 7.5, was brought to pH 5.5 with 3.5 M acetic acid, and the supernatant fractio...

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Role of Aldolase in Photosynthesis. II Demonstration of Aldolase Types in Photosynthetic Organisms

Cited by 42 publications

References 14 publications

Isoenzymes of the Glycolytic and Pentose Phosphate Pathways in Proplastids from the Developing Endosperm of Ricinis communis L.

Isoenzymes of the Glycolytic and Pentose Phosphate Pathways in Proplastids from the Developing Endosperm of Ricinis communis L.

Carboxysomes:‘calvinosomes’?

Chloroplast and Cytoplasmic Enzymes

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