Structure and functioning mechanism of transketolase

Kochetov, G. A.; Solovjeva, Olga N.

doi:10.1016/j.bbapap.2014.06.003

Cited by 68 publications

(68 citation statements)

References 58 publications

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“…The substrates of the pentose phosphate pathway are then used for the synthesis of nucleic acids, complex sugar molecules, coenzymes, steroids, fatty acids, amino acids, neurotransmitters, and glutathione. Through its operation, TK also connects the pentose pathway with the glycolysis …”

Section: Biochemical Mode Of Action and Role In The Nervous Systemmentioning

confidence: 99%

B Vitamins in the nervous system: Current knowledge of the biochemical modes of action and synergies of thiamine, pyridoxine, and cobalamin

2019

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Background Neurotropic B vitamins play crucial roles as coenzymes and beyond in the nervous system. Particularly vitamin B1 (thiamine), B6 (pyridoxine), and B12 (cobalamin) contribute essentially to the maintenance of a healthy nervous system. Their importance is highlighted by many neurological diseases related to deficiencies in one or more of these vitamins, but they can improve certain neurological conditions even without a (proven) deficiency. Aim This review focuses on the most important biochemical mechanisms, how they are linked with neurological functions and what deficits arise from malfunctioning of these pathways. Discussion We discussed the main role of B Vitamins on several functions in the peripheral and central nervous system (PNS and CNS) including cellular energetic processes, antioxidative and neuroprotective effects, and both myelin and neurotransmitter synthesis. We also provide an overview of possible biochemical synergies between thiamine, pyridoxine, and cobalamin and discuss by which major roles each of them may contribute to the synergy and how these functions are inter‐related and complement each other. Conclusion Taking into account the current knowledge on the neurotropic vitamins B1, B6, and B12, we conclude that a biochemical synergy becomes apparent in many different pathways in the nervous system, particularly in the PNS as exemplified by their combined use in the treatment of peripheral neuropathy.

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Section: Biochemical Mode Of Action and Role In The Nervous Systemmentioning

confidence: 99%

B Vitamins in the nervous system: Current knowledge of the biochemical modes of action and synergies of thiamine, pyridoxine, and cobalamin

2019

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“…The pentose phosphate pathway is important to maintain carbon homoeostasis, to provide precursors for nucleotide and amino acid biosynthesis, and to provide reducing molecules for defeating oxidative stress Stincone et al (2014). TK is the key enzyme of the non-oxidative branch of the pentose phosphate pathway of carbohydrate transformation (Kochetov and Solovjeva 2014). Accumulation of TK would promote the enhancement of the non-oxidative branch, yielding Data are presented as average values of five biological replicates ± SE One-way ANOVA was used to test the differences between control and treatment at each time point…”

Section: Carbohydrate and Energy Metabolismmentioning

confidence: 99%

Global proteomic mapping of alkali stress regulated molecular networks in Helianthus tuberosus L.

et al. 2016

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Background and aims Soil salinization with high pH condition is a major abiotic stress to plant growth and crop productivity. Helianthus tuberosus L. is an important stress tolerant plant and can survive in the salinealkali soil and semiarid areas. The aim of this study is to identify the effect of alkali stress on H. tuberosus through global proteomics analysis and improve understanding of the alkalinity resistance of plants. Methods H. tuberosus seedlings were exposed to different level alkali stress for 7 days. Protein profiling was quantified by conducting MS-based comparative proteomics analysis. RT-PCR study was carried out to analyze the mRNA expression levels of candidate alkali stress response proteins. Results The response of H. tuberosus to alkali stress was detected at both physiological and molecular levels. 104 differentially expressed proteins from H. tuberosus leaves response to Na 2 CO 3 treatment were successfully identified.Functional categorization of these identified proteins showed that the accumulation level of proteins involved in glycolysis, TCA cycle, PSI system, ROS scavenging and signal transduction increased under alkali stress. Conclusions Based on the observation of plant growth and the investigation of molecular regulation, H.tuberosus could resist certain alkali stress by modulating carbohydrate metabolism and redox homeostasis. These findings provide a new sight into the underlying molecular mechanisms of alkali resistance in plant.

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“…The isomerase converts the carbon 2 ketose to a carbon 1 aldose, yielding ribose-5-phosphate (R5P); the epimerase reverses the stereochemistry of the carbon 3 hydroxyl in Ri5P to yield the ketose xylulose-5-phosphate (X5P). Transketolase has broad substrate specificity and catalyzes the transfer of two carbons from a ketose (having specific hydroxyl configurations surrounding the keto group) to carbon 1 of an aldose (Kochetov and Solovjeva, 2014). In this case, the first two carbons of X5P are transferred to carbon 1 of R5P, forming the new ketose sedoheptulose-7-phosphate (S7P) and the three carbon aldose G3P (Fig.…”

Section: Resultsmentioning

confidence: 99%

Updates to a 13 C metabolic flux analysis model for evaluating energy metabolism in cultured cerebellar granule neurons from neonatal rats

Jekabsons

Gebril

Wang

et al. 2017

Neurochemistry International

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A hexose phosphate recycling model previously developed to infer fluxes through the major glucose consuming pathways in cultured cerebellar granule neurons (CGNs) from neonatal rats metabolizing [1,2-13C2]glucose was revised by considering reverse flux through the non-oxidative pentose phosphate pathway (PPP) and symmetrical succinate oxidation within the tricarboxylic acid (TCA) cycle. The model adjusts three flux ratios to effect 13C distribution in the hexose, pentose, and triose phosphate pools, and in TCA cycle malate to minimize the error between predicted and measured 13C labeling in exported lactate (i.e., unlabeled, single-, double-, and triple-labeled; M, M1, M2, and M3, respectively). Inclusion of reverse non-oxidative PPP flux substantially increased the number of calculations but ultimately had relatively minor effects on the labeling of glycolytic metabolites. From the error-minimized solution in which the predicted M-M3 lactate differed by 0.49% from that measured by liquid chromatography-triple quadrupole mass spectrometry, the neurons exhibited negligible forward non-oxidative PPP flux. Thus, no glucose was used by the pentose cycle despite explicit consideration of hexose phosphate recycling. Mitochondria consumed only 16% of glucose while 45% was exported as lactate by aerobic glycolysis. The remaining 39% of glucose was shunted to pentose phosphates presumably for de novo nucleotide synthesis, but the proportion metabolized through the oxidative PPP vs. the reverse non-oxidative PPP could not be determined. The lactate exported as M1 (2.5%) and M3 (1.2%) was attributed to malic enzyme, which was responsible for 7.8% of pyruvate production (vs. 92.2% by glycolysis). The updated model is more broadly applicable to different cell types by considering bi-directional flux through the non-oxidative PPP. Its application to cultured neurons utilizing glucose as the sole exogenous substrate has demonstrated substantial oxygen-independent glucose utilization by aerobic glycolysis as well as the oxidative PPP and/or reverse non-oxidative PPP, but negligible glucose consumption by the pentose cycle.

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Structure and functioning mechanism of transketolase

Cited by 68 publications

References 58 publications

B Vitamins in the nervous system: Current knowledge of the biochemical modes of action and synergies of thiamine, pyridoxine, and cobalamin

B Vitamins in the nervous system: Current knowledge of the biochemical modes of action and synergies of thiamine, pyridoxine, and cobalamin

Global proteomic mapping of alkali stress regulated molecular networks in Helianthus tuberosus L.

Updates to a 13 C metabolic flux analysis model for evaluating energy metabolism in cultured cerebellar granule neurons from neonatal rats

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