Photosynthesis in Rhodospirillum rubrum. III. Metabolic Control of Reductive Pentose Phosphate and Tricarboxylic Acid Cycle Enzymes

1. The metabolism of incubated slices of sponge-induced granulation tissue, harvested 4–90 days after the implantation, was studied with special reference to the capacity of collagen synthesis and to the energy metabolism. Data are also given on the nucleic acid contents during the observation period. Three metabolic phases were evident. 2. The viability of the slices for the synthesis of collagen was studied in various conditions. Freezing and homogenization destroyed the capacity of the tissue to incorporate proline into collagen. 3. Consumption of oxygen reached the maximum at 30–40 days. There was evidence that the pentose phosphate cycle was important, especially during the phases of the proliferation and the involution. The formation of lactic acid was maximal at about 20 days. 4. The capacity to incorporate proline into collagen hydroxyproline in vitro was limited to a relatively short period at 10–30 days. 5. The synthesis of collagen was dependent on the supply of oxygen and glucose, which latter could be replaced in the incubation medium by other monosaccharides but not by the metabolites of glucose or tricarboxylic acid-cycle intermediates.

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Carbohydrate metabolism in Acanthamoeba castellanii. 1. The activity of key enzymes and [14C]-glucose metabolism

Canadian Journal of Microbiology ◽

10.1139/m73-180 ◽

1973 ◽

Vol 19 (9) ◽

pp. 1131-1136 ◽

Cited By ~ 8

Author(s):

Lansing M. Prescott ◽

Harold E. Hoyme ◽

Darlene Crockett ◽

Elena Hui

Keyword(s):

Carbohydrate Metabolism ◽

Citrate Synthase ◽

Tricarboxylic Acid Cycle ◽

Fumarate Hydratase ◽

Acanthamoeba Castellanii ◽

Tricarboxylic Acid ◽

Pentose Phosphate ◽

Acid Cycle ◽

Key Enzymes ◽

Glyceraldehydephosphate Dehydrogenase

The specific activities of a number of the key enzymes involved in carbohydrate metabolism in Acanthamoeba castellanii (Neff clone I–12) have been determined. The following Embden–Meyerhof and pentose phosphate pathway enzymes were present: glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, hexokinase, phosphofructokinase, hexose diphosphatase, aldolase, glyceraldehydephosphate dehydrogenase, pyruvate kinase, and pyruvate-phosphate dikinase. The following tricarboxylic acid cycle enzymes were also found: citrate synthase, aconitase, isocitrate dehydrogenase, succinate dehydrogenase, fumarate hydratase, and malate dehydrogenase. The degradation of glucose-U-14C to 14CO2 was examined. Aerobic 14CO2 production from glucose-U-14C was 3.4-fold greater than anaerobic production. The data provide further evidence that the Embden–Meyerhof, pentose phosphate, and tricarboxylic acid cycle pathways are probably functional in A. castellanii.

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Glucose metabolism and its regulation in pieces of perirenal adipose tissue from foetal lambs

Biochemical Journal ◽

10.1042/bj2100677 ◽

1983 ◽

Vol 210 (3) ◽

pp. 677-683 ◽

Cited By ~ 2

Author(s):

J P Robertson ◽

A Faulkner ◽

R G Vernon

Keyword(s):

Adipose Tissue ◽

Glucose Metabolism ◽

Pyruvate Dehydrogenase ◽

Glucose Utilization ◽

Tricarboxylic Acid Cycle ◽

Tricarboxylic Acid ◽

Pentose Phosphate ◽

Acid Cycle ◽

Near Term ◽

Glucose 6 Phosphate Dehydrogenase

1. The following were measured in pieces of perirenal adipose tissue obtained from foetal lambs at about 120 days of gestation or within 3 days of term, and 9-month-old sheep: the rates of synthesis from glucose of fatty acids, acylglycerol glycerol, pyruvate and lactate; the rate of glucose oxidation to CO2 and the proportions contributed by the pentose phosphate cycle, pyruvate dehydrogenase and the tricarboxylic acid cycle; the activities of hexokinase, glucose 6-phosphate dehydrogenase, phosphofructokinase, pyruvate kinase and pyruvate dehydrogenase. 2. The total rate of glucose utilization was lower in pieces of adipose tissue from near-term lambs than 120-day foetal lambs and the pattern of glucose metabolism differed, with, for example, a much smaller proportion of glucose carbon being used for fatty acid synthesis, whereas a greater proportion of glucose oxidation occurred via the tricarboxylic acid cycle in the near-term lambs. In general, these differences in glucose metabolism were not associated with differences in the activities of the various enzymes listed above. 3. The rates of glucose utilization per fat-cell by 120-day foetal lambs and 9-month-old sheep were very similar but, again, the proportions metabolized to the various products differed. In particular, there was a smaller proportion of glucose oxidized via the pentose phosphate cycle and a greater proportion oxidized via pyruvate dehydrogenase and the tricarboxylic acid cycle in adipose tissue from foetal lambs. These differences were matched by a lower activity of glucose 6-phosphate dehydrogenase and a higher pyruvate dehydrogenase activity in fat-cells from the foetal lambs.

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Upregulation of Pentose Phosphate Pathway and Preservation of Tricarboxylic Acid Cycle Flux after Experimental Brain Injury

Journal of Neurotrauma ◽

10.1089/neu.2005.22.1052 ◽

2005 ◽

Vol 22 (10) ◽

pp. 1052-1065 ◽

Cited By ~ 82

Author(s):

Brenda L. Bartnik ◽

Richard L. Sutton ◽

Masamichi Fukushima ◽

Neil G. Harris ◽

David A. Hovda ◽

...

Keyword(s):

Brain Injury ◽

Pentose Phosphate Pathway ◽

Tricarboxylic Acid Cycle ◽

Tricarboxylic Acid ◽

Pentose Phosphate ◽

Acid Cycle

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Reductive tricarboxylic acid cycle enzymes and reductive amino acid synthesis pathways contribute to electron balance in a Rhodospirillum rubrum Calvin-cycle mutant

Microbiology ◽

10.1099/mic.0.000877 ◽

2020 ◽

Vol 166 (2) ◽

pp. 199-211 ◽

Cited By ~ 4

Author(s):

Alexandra L. McCully ◽

Maureen C. Onyeziri ◽

Breah LaSarre ◽

Jennifer R. Gliessman ◽

James B. McKinlay

Keyword(s):

Amino Acid ◽

Rhodospirillum Rubrum ◽

Tricarboxylic Acid Cycle ◽

Calvin Cycle ◽

Acid Synthesis ◽

Tricarboxylic Acid ◽

Amino Acid Synthesis ◽

Acid Cycle ◽

Electron Balance ◽

Reductive Tricarboxylic Acid Cycle

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Studies in the respiratory and carbohydrate metabolism of plant tissues - X. The influence of oxygen at high pressures as a stimulant and inhibitor of certain pathways of respiration in carrots

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1961.0033 ◽

1961 ◽

Vol 154 (956) ◽

pp. 289-308 ◽

Cited By ~ 2

Keyword(s):

High Pressures ◽

Tricarboxylic Acid Cycle ◽

Tricarboxylic Acid ◽

Pentose Phosphate ◽

High Oxygen ◽

Total Carbon ◽

Inhibitory Effects ◽

Acid Cycle ◽

Concentration Changes ◽

Oxygen Poisoning

In contrast with the behaviour of peas (Turner & Quartley 1956; Pritchard 1959, 1961) but like that of various tissues (Johannsen 1888; Cass 1947; Barker, Quartley & Turner 1960), the rate of CO 2 output of whole carrots was stimulated initially in oxygen at a pressure of 5 atm prior to the strong inhibition characteristic of oxygen poisoning. The inhibition was associated with an accumulation of citrate together with a decrease in the contents of α -ketoglutarate, succinate, malate and oxaloacetate; later pyruvate, alcohol and acetate also increased. As in the earlier work with potatoes, peas and apples (Barker & Mapson 1955; Turner & Quartley 1956; Barker et al . 1960), these changes in the acids were attributed in part to the production of an enzymic ‘block’ first in the tricarboxylic acid cycle between citrate and α -ketoglutarate and later in the oxidation of pyruvate. The earlier observations of the activity of the tricarboxylic acid cycle in carrot slices were thus confirmed (Pritchard 1959; ap Rees & Beevers 1960). The ‘total carbon traffic’, representing the sum of the observed CO 2 output in high oxygen and the calculated amounts of CO 2 that would be derived by oxidation of the accumulations of citrate, pyruvate, alcohol and acetate, increased initially in high oxygen to a rate which was about double that of the CO 2 output in air. Considered in relation to this increased carbon traffic in respiration, there was thus initially in high oxygen a large inhibition of the CO 2 output. Oxygen at high pressures thus produced simultaneous stimulatory and inhibitory effects on certain phases of the respiratory process in carrots. Initially in high oxygen only a small part of the CO 2 output could be accounted for by the observed concentration changes: e. g. the accumulation of citrate; a part of the ‘unknown’ CO 2 output is provisionally attributed, without direct evidence, to operation of the pentose phosphate pathway, earlier shown to be active in carrot slices (Beevers & Gibbs 1954; ap Rees & Beevers 1960).

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On the Relation Between TSH AdministrationIn Vivoand the Activities of Several Glycolytic, Pentose Phosphate Pathway and Tricarboxylic Acid Cycle Enzymes in the Rat Thyroid Gland

Israel Journal of Chemistry ◽

10.1002/ijch.196900074 ◽

1969 ◽

Vol 7 (4) ◽

pp. 567-573 ◽

Cited By ~ 2

Author(s):

L. Kopelovich

Keyword(s):

Thyroid Gland ◽

Pentose Phosphate Pathway ◽

Tricarboxylic Acid Cycle ◽

Tricarboxylic Acid ◽

Pentose Phosphate ◽

Acid Cycle ◽

Rat Thyroid ◽

Rat Thyroid Gland

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Maximum activities of key enzymes of glycolysis, glutaminolysis, pentose phosphate pathway and tricarboxylic acid cycle in normal, neoplastic and suppressed cells

Biochemical Journal ◽

10.1042/bj2650503 ◽

1990 ◽

Vol 265 (2) ◽

pp. 503-509 ◽

Cited By ~ 129

Author(s):

M Board ◽

S Humm ◽

E A Newsholme

Keyword(s):

Pyruvate Kinase ◽

Pentose Phosphate Pathway ◽

Tricarboxylic Acid Cycle ◽

Tricarboxylic Acid ◽

Pentose Phosphate ◽

Neoplastic Cells ◽

Acid Cycle ◽

Key Enzymes ◽

Metastatic Cells ◽

Tumorigenic Cells

1. Maximal activities of some key enzymes of glycolysis, the pentose phosphate pathway, the tricarboxylic acid cycle and glutaminolysis were measured in homogenates from a variety of normal, neoplastic and suppressed cells. 2. The relative activities of hexokinase and 6-phosphofructokinase suggest that, particularly in neoplastic cells, in which the capacity for glucose transport is high, hexokinase could approach saturation in respect to intracellular glucose; consequently, hexokinase and phosphofructokinase could play an important role in the regulation of glycolytic flux in these cells. 3. The activity of pyruvate kinase is considerably higher in tumorigenic cells than in non-tumorigenic cells and higher in metastatic cells than in tumorigenic cells: for non-tumorigenic cells the activities range from 28.4 to 574, for tumorigenic cells from 899 to 1280, and for metastatic cells from 1590 to 1627 nmol/min per mg of protein. 4. The ratio of pyruvate kinase activity to 2 x phosphofructokinase activity is very high in neoplastic cells. The mean is 22.4 for neoplastic cells, whereas for muscle from 60 different animals it is only 3.8. 5. Both citrate synthase and isocitrate dehydrogenase activities are present in non-neoplastic and neoplastic cells, suggesting that the full complement of tricarboxylic-acid-cycle enzymes are present in these latter cells. 6. In neoplastic cells, the activity of glutaminase is similar to or greater than that of hexokinase, which suggests that glutamine may be as important as glucose for energy generation in these cells.

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