Acid metabolism

Fatty acids are an important energy source, for they yield over twice as much energy as an equal mass of carbohydrate or protein. In humans, the primary dietary source of fatty acids is triacylglycerols. This lecture will describe the metabolism of fatty acids. The two main components of fatty acid metabolism are β oxidation and fatty acid synthesis. Upon completion of this lecture, you will understand that the fatty-acid breakdown reactions of β oxidation result in the formation of reduced cofactors and acetyl-CoA molecules, which can be further catabolized to release free energy.

64p zingzing09 21-10-2012 106 10   Download

Early metabolic steps, including glycolysis and the activity of the pyruvate dehydrogenase complex, yield a two-carbon fragment called an acetyl group, which is linked to a large cofactor known as coenzyme A (or CoA). It is during the citric acid cycle that acetyl-CoA is oxidized to the waste product, carbon dioxide, along with the reduction of the cofactors NAD+ and ubiquinone

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Tham khảo bài thuyết trình 'chapter 5. lipid metabolism', khoa học tự nhiên, công nghệ sinh học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả

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Bài giảng Sinh lý học thực vật: Chương 4 Quang hợp, cung cấp cho người học những kiến thức như: Khái niệm, các hình thức tiến hoá và ý nghĩa quang hợp; Pha tối quang hợp; Chu trình CAM (Crassulacean Acid Metabolism); Quang hợp với năng suất cây trồng;...Mời các bạn cùng tham khảo!

66p caphesuadathemhanh 03-12-2021 24 3   Download

Carbohydrate Metabolism: Glycolysis, Citric acid cycle, Gluconeogenesis, Glycogen metabolism. Invite you to consult for additional documents for the academic needs and research.

22p kimtuoi2410 22-09-2015 59 2   Download

Certain amino acids, like glutamine and leucine, induce an anabolic response in liver. They activate p70 ribosomal protein S6 kinase (p70S6K) and acetyl-CoA carboxylase (ACC) involved in protein and fatty acids synthesis, respectively. In contrast, the AMP-activated protein kinase (AMPK), which senses the energy state of the cell and becomes activated under metabolic stress, inactivates by phosphorylation key enzymes in biosynthetic pathways thereby conserving ATP.

9p system191 01-06-2013 50 5   Download

Liver metabolism is influenced by hormones and nutrients. Amino acids such as glutamine or leucine induce an anabolic response, which resembles that of insulin in muscle and adipose tissue. In this work, the signalling pathways and the effects of insulin were compared to those of glutamine and leucine in isolated hepatocytes from normal and streptozotocin-diabetic rats.

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Modelling of the fluxes in central metabolism can be performed by combining labelling experiments with metabolite balancing. Using this approach, multiple samples from a cultivation of Saccharomyces cerevisiae in metabolic and isotopic steady state were analysed, and the metabolic fluxes in central metabolism were estimated. In the various samples, the estimates of the central metabolic pathways, the tricarboxylic acid cycle, the oxidative pentose phosphate pathway and the anaplerotic pathway, showed an unprecedented reproducibility....

6p system191 01-06-2013 43 2   Download

The citric acid or tricarboxylic acid cycle is a central element of higher-plant carbon metabolism which provides, among other things, electrons for oxidative phosphorylation in the inner mitochondrial membrane, intermediates for aminoacid biosynthesis, and oxaloacetate for gluconeogenesis from succinate derived from fatty acids via the glyoxylate cycle in glyoxysomes. The tricarboxylic acid cycle is a typical mitochondrial pathway and is widespread among a-proteobacteria, the group of eubacteria as de®ned under rRNA systematics from which mitochondria arose. ...

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Alcohol dehydrogenase (ADH) deficiency results in decreased retinol utilization, but it is unclear what physio-logical roles the several known ADHs play in retinoid signaling. Here, Adh1, Adh3,andAdh4null mutant mice have been examined following acute and chronic vitamin A excess. Following an acute dose of retinol (50 mgÆkg )1 ), metabolism of retinol to retinoic acid in liver was reduced 10-fold inAdh1mutants and 3.8-fold inAdh3mutants, but was not significantly reduced inAdh4mutants.

6p research12 29-04-2013 52 3   Download

Biosynthesis of cholesterol represents one of the funda-mental cellular metabolic processes. SterolD14-reductase (D14-SR) is a microsomal enzyme involved in the con-version of lanosterol to cholesterol in mammals. Amino-acid sequence analysis of a 38-kDa protein puri®ed from bovine liver in our laboratory revealed 90% similarity with a human sterol reductase, SR-1, encoded by the TM7SF2gene, and with the C-terminal domain of human lamin B receptor.

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Protein synthesis requires both amino acids, as precursors, and a substantial amount of metabolic energy. It is well established that starvation or lack of nutrients impairs pro-tein synthesis in mammalian cells and tissues. Branched chain amino acids are particularly effective in promoting protein synthesis. Recent work has revealed important new information about the mechanisms involved in these effects. Anumber of components of the translational machinery are regulated through signalling events that require the mam-malian target of rapamycin, mTOR. ...

12p tumor12 22-04-2013 35 2   Download

Epoxide hydrolase (EC 3.3.2.3) in plants is involved in the metabolism of epoxy fatty acids and in mediating defence responses. We report the cloning of a full-length epoxide hydrolase cDNA (BNSEH1) from oilseed rape (Brassica napus) obtained by screening of a cDNA library prepared frommethyl jasmonate induced leaf tissue, and the5¢-RACE technique. The cDNA encodes a soluble protein containing 318 amino acid residues.

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Anandamide is an endogenous ligand for cannabinoid receptor and its protein-mediated transport across cellular membranes has been demonstrated in cells derived from brain as well as in cells of the immune system. This lipid is inactivated via intracellular degradation by a fatty acid amidohydrolase (FAAH). In the present study, we report that rabbit platelets, in contrast to human platelets, do not possess a carrier-mediated mechanism for the transport of [ 3 H]anandamide into the cell, i.e. cellular uptake was not temperature dependent and its accumulation was not satu-rable. ...

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The localization of different classes of alcohol dehydro-genases (ADH) in the brain is of great interest because of their role in both ethanol and retinoic acid metabolism. Conflicting data have been reported in the literature. By Northern blot and enzyme activity analyses only class III ADH has been detected in adult brain specimens, while results from riboprobe in situ hybridization indicate class I as well as class IV ADH expression in different regions of the rat brain.

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Anumber of cellular systems cooperate in redox regulation, providing metabolic responses according to changes in the oxidation (or reduction)of the redox active components of a cell. Key systems of central metabolism, such as the 2-oxo acid dehydrogenase complexes, are important participants in redox regulation, because their function is controlled by the NADH/NAD + ratio and the complex-bound dihydro-lipoate/lipoate ratio.

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Corynebacterium ammoniagenesis an overproducer of xanthosine-5¢-monophosphate (XMP) by consuming either glcose (glc) or glutamic acid (glu). Its energymetabolismwas studiedin vivousing 31 P NMR spectroscopy coupled with a circulating fermentation system (CFS). CFS enabled us to validate directly the cellular dependency on carbon sources and changes in biomolecules produced according to altera-tions in the cellular energetic status.

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Erythrocytic stages of the malaria parasitePlasmodium fal-ciparumrely on glycolysis for their energy supply and it is unclear whether they obtain energy via mitochondrial res-piration albeit enzymes of the tricarboxylic acid (TCA) cycle appear to be expressed in these parasite stages. Isocitrate dehydrogenase (ICDH) is either an integral part of the mitochondrial TCA cycle or is involved in providing NADPH for reductive reactions in the cell.

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Spontaneous oxidation of 3-hydroxykynureine (3-HK), a metabolic inter-mediate of the tryptophan degradation pathway, elicits a remarkable oxida-tive stress response in animal tissues. In the yellow fever mosquito Aedes aegyptithe excess of this toxic metabolic intermediate is efficiently removed by a specific 3-HK transaminase, which converts 3-HK into the more sta-ble compound xanthurenic acid.

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Oxysterol binding protein (OSBP) and its homologs have been shown to regulate lipid metabolism and vesicular transport. However, the exact molecular function of individual OSBP homologs remains uncharacterized. Here we demonstrate that the yeast OSBP homolog, Osh6p, bound phos-phatidic acid and phosphoinositides via its N-terminal half containing the conserved OSBP-related domain (ORD). Using a green fluorescent protein fusion chimera, Osh6p was found to localize to the cytosol and patch-like or punctate structures in the vicinity of the plasma membrane....

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