Metabolism of glucose

It affects the metabolisms of glucose and proteins used in rheumatoid arthritis, inflammatory conditions, etc. 

The biological transformations that involve ATP are both numerous and funda mental They include for example many phosphorylation reactions m which ATP trans fers one of its phosphate units to the —OH of another molecule These phosphoryla tions are catalyzed by enzymes called kinases An example is the first step m the metabolism of glucose... 

The pentose phosphate pathway is an alternative route for the metabolism of glucose. It does not generate ATP but has two major functions (1) The formation of NADPH for synthesis of fatty acids and steroids and (2) the synthesis of ribose for nucleotide and nucleic acid formation. Glucose, fructose, and galactose are the main hexoses absorbed from the gastrointestinal tract, derived principally from dietary starch, sucrose, and lactose, respectively. Fructose and galactose are converted to glucose, mainly in the liver. 

FRET-based nanosensors have been successfully used to monitor steady state levels of metabolites, nutrients, and ions in mammalian cells [74, 87], Recently FRET-based glucose, sucrose, and amino acid nanosensors have been developed to study the metabolism of glucose, sucrose, and amino acid uptake and metabolism in plant cells [80,89, 91]. The enormous potential of these nanosensors will be crucial for understanding ion (e.g., calcium), metabolite (e.g., sugars), hormone (e.g., auxins, gibberellins etc.), and nutrient (e.g., nitrogen, potassium, phosphorus) requirements and homeostasis in living plant tissues. 

Deuschle, K., Chaudhuri, B., Okumoto, S., Lager, I., Lalonde, S. and Frommer, W. B. (2006). Rapid metabolism of glucose detected with FRET glucose nanosensors in epidermal cells and intact roots of Arabi-dopsis RNA-silencing mutants. Plant Cell 18, 2314-25. 

Since the brain utilizes energy almost exclusively from oxidative metabolism of glucose, brain metabolism has been studied by focusing on net oxygen and glucose uptake. Oxygen consumption was classically measured as the arteriovenous difference of 02 content. When a substance is exchanged between brain and blood, the difference between its steady state of delivery to brain in the arterial blood and removal in the venous blood must be equal to the net rate of its utilization or... 

Hasselbalch, S. G., Knudsen, G. M., Capaldo, B. etal. Blood-brain barrier transport and brain metabolism of glucose during acute hyperglycemia in humans. /. Clin. Endocrinol. Metab. 86 1986-1990, 2001. 

Sakhrani, L.M., Badie-Dezfooly, B., Trizna, W., Mikhails, N., Lowe, A., Taub, M. and Fine, L.G. (1984). Transport and metabolism of glucose by renal proximal tubular cells in primary culture. Amer. J. Physiol. 246 F757-F764. 

Insulin, a hormone produced by the pancreas, is essential for the metabolism of glucose, proteins, and fats. Insulins are classified on the basis of the duration of action as rapid-, intermediate-, or long-acting and on the basis of source or species, such as human or animal (beef, pork, and mixtures of beef and pork). Table 10.1 summarizes insulin preparations currendy available in the United States. 

Some enzyme-catalysed reactions result in the production or uptake of a gas and some of the earliest assay methods used this phenomenon as a basis for monitoring the reaction. Classically, Krebs, in elucidating the metabolism of glucose, used such methods. They measure either the pressure changes that... 

A paper published six decades ago was the first to draw attention to the possibility that a change in the rate of transport of a molecule across the plasma membrane conld play a role in regulation of both intra- and extracellnlar metabolism that is, the regulation of the blood glncose level and the intracellular metabolism of glucose. The paper was entitlied A hypothesis of insulin action is proposed which attributes to insulin the role of facilitating the rate of transport of some hexoses into the cell as opposed to a direct effect on intracellular metabolism (Levine et al. 1950). 

Figure 9.6 Sequence of electron carriers in the electron transfer chain. The positions of entry into the chain from metabolism of glucose, glutamine, fatty acyl-CoA, glycerol 3-phosphate and others that are oxidised by the Krebs cycle are shown. The chain is usually considered to start with NADH and finish with cytochrome oxidase. FMN is flavin mononucleotide FAD is flavin adenine dinucleotide.

As with all the major transmitters, acetylcholine is stored in vesicles within the nerve terminal from which it is released by a calcium-dependent mechanism following the passage of a nerve impulse. The inter-relationship between the intermediary metabolism of glucose, phospholipids and the uptake of choline is summarized in Figure 2.14. 

Figure 2.14 Iriter-relationship between intermediary. metabolism of glucose, phospholipids and acetylcholine synthesis. Acetyl CoA acetyl coenzyme A CAT-catechol-O-methyltransferase AChE acetylcholinesterase.

The bottom line for any of the above disorders is that insulin action is lost. Insulin is the primary hormone that regulates the metabolism of glucose in its conversion to the storage of carbohydrate—glycogen stored in the liver and muscles. Insulin also... 

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