scholarly journals The Effect ofWalterinnesia aegyptiaVenom Proteins on TCA Cycle Activity and Mitochondrial NAD+-Redox State in Cultured Human Fibroblasts

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Hazem K. Ghneim ◽  
Yazeed A. Al-Sheikh ◽  
Mourad A. M. Aboul-Soud

Fibroblast cultures were used to study the effects of crudeWalterinnesia aegyptiavenom and its F1–F7 protein fractions on TCA cycle enzyme activities and mitochondrial NAD-redox state. Confluent cells were incubated with 10 μg of venom proteins for 4 hours at 37°C. The activities of all studied TCA enzymes and the non-TCA mitochondrial NADP+-dependent isocitrate dehydrogenase underwent significant reductions of similar magnitude (50–60% of control activity) upon incubation of cells with the crude venom and fractions F4, F5, and F7 and 60–70% for fractions F3 and F6. In addition, the crude and fractions F3–F7 venom proteins caused a drop in mitochondrial NAD+and NADP+levels equivalent to around 25% of control values. Whereas the crude and fractions F4, F5, and F7 venom proteins caused similar magnitude drops in NADH and NADPH (around 55% of control levels), fractions F3 and F6 caused a more drastic drop (60–70% of control levels) of both reduced coenzymes. Results indicate that the effects of venom proteins could be directed at the mitochondrial level and/or the rates of NAD+and NADP+biosynthesis.

HortScience ◽  
1991 ◽  
Vol 26 (2) ◽  
pp. 171-173 ◽  
Author(s):  
Shiow Y. Wang ◽  
Hong J. Jiao ◽  
Miklos Faust

The activity of glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphate gluconate dehydrogenase (6PGDH), isocitrate dehydrogenase (ICDH), pyruvate kinase (PK), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were studied in apple (Malus domestics Borkh.) buds during dormancy and thidiazuron-induced budbreak. When buds were dormant, the activity of the glycolytic enzymes GAPDH and PK and the tricarboxylic acid (TCA) cycle enzyme ICDH was low compared to that in nondormant buds. The activity of these enzymes increased during budbreak, peaked when buds were in the green tip stage just before the start of rapid expansion (at 8 days after thidiazuron treatment), and declined thereafter. The activity of pentose-phosphate cycle enzymes G6PDH and 6PGDH was higher in dormant buds than in nondormant buds. 6PGDH was about twice as high as G6PDH. During budbreak and resumption of growth, G6PDH and 6PGDH activity decreased.


1988 ◽  
Vol 263 (26) ◽  
pp. 12886-12892 ◽  
Author(s):  
H Greve ◽  
Z Cully ◽  
P Blumberg ◽  
H Kresse

1987 ◽  
Vol 262 (36) ◽  
pp. 17412-17419 ◽  
Author(s):  
W B Rizzo ◽  
D A Craft ◽  
A L Dammann ◽  
M W Phillips

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 762
Author(s):  
Edward V. Prochownik ◽  
Huabo Wang

Pyruvate occupies a central metabolic node by virtue of its position at the crossroads of glycolysis and the tricarboxylic acid (TCA) cycle and its production and fate being governed by numerous cell-intrinsic and extrinsic factors. The former includes the cell’s type, redox state, ATP content, metabolic requirements and the activities of other metabolic pathways. The latter include the extracellular oxygen concentration, pH and nutrient levels, which are in turn governed by the vascular supply. Within this context, we discuss the six pathways that influence pyruvate content and utilization: 1. The lactate dehydrogenase pathway that either converts excess pyruvate to lactate or that regenerates pyruvate from lactate for use as a fuel or biosynthetic substrate; 2. The alanine pathway that generates alanine and other amino acids; 3. The pyruvate dehydrogenase complex pathway that provides acetyl-CoA, the TCA cycle’s initial substrate; 4. The pyruvate carboxylase reaction that anaplerotically supplies oxaloacetate; 5. The malic enzyme pathway that also links glycolysis and the TCA cycle and generates NADPH to support lipid bio-synthesis; and 6. The acetate bio-synthetic pathway that converts pyruvate directly to acetate. The review discusses the mechanisms controlling these pathways, how they cross-talk and how they cooperate and are regulated to maximize growth and achieve metabolic and energetic harmony.


1971 ◽  
Vol 42 (2) ◽  
pp. 340-345 ◽  
Author(s):  
Reuben Matalon ◽  
J.A. Cifonelli ◽  
Albert Dorfman

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