Glucose-6-phosphate dehydrogenase G-6-PDH

Adding glucose-6-phosphate dehydrogenase (G-6-PDH) in the presence of oxidized nicotinamide adenine trinucleotide (NADH) yields gluconic acid-6-phosphate and an equivalent amount of the reduced form, NADPH. The amount of NADPH can be measured from its absorbance at 340 nm. For fructose the first reaction is ... 

Fig. 9. Sequence of transformations catalysed by the supramolecular ATP-generating system [38, AcP, Mg2, ADP] (38 = [24]-N6C>2) and the enzymes hexokinase (HK), glucose-6-phosphate dehydrogenase (G-6-PDH) and 6-phospho-gluconate dehydrogenase (6-P-GDH) [5.32],...

Enzymes Alkaline phosphatase, horseradish peroxidase (FIRP), glucose-6-phosphate dehydrogenase (G-6-PDH), malate dehydrogenase (MDH), NADH dehydrogenase, acetylcholinesterase... 

Divicine and isouramil are believed to provoke haemolysis by oxidation of glutathione in the erythrocyte, which upsets the intracellular redox balance. In normal individuals, glutathione is maintained in the reduced form by an NADPH-dependent reductase and the NAD PH is supplied by the pentose phosphate pathway involving glucose-6-phosphate dehydrogenase (G-6-PDH) ... 

The results of one of the first multistep enzyme systems to be immobilized were presented in 1970 by Mosbach and Mattiasson (3). They covalently bonded hexokinase (HK) and glucose-6-phosphate dehydrogenase (G-6-PDH) to individual polymer particles via the cyanogen bromide reaction. Using a solution containing glucose, ATP and NADP" ", they demonstrated that the coimmobilized enzymes formed product... 

Glucose-6-phosphate dehydrogenase activity. Oil, administered to rats, reduced the G 6 PDH activity of lymphocytes hy 16% and the activity of G 6-PDH in liver by... 

Glucose-6-phosphate-dehydrogenase (microbial) G-6-PDH 75.56% Non-reactive components... 

Many examples of product inhibition are to found. Some dehydrogenases are inhibited by NADH (a co-product of the reaction), e.g. PDH and isocitrate dehydrogenase (ICD), which are involved with the glycolysis and the TCA cycle are two such examples. Hexokinase isoenzymes in muscle (but not liver) and citrate synthase are inhibited by their products, glucose-6-phosphate and citrate respectively offering a very immediate fine tuning of reaction rate to match cellular requirements and possibly allowing their substrates to be used in alternative pathways. 

Fig. 1 Oxidative metabolism and energy production by mitochondria. The oxidation of pyruvate and free fatty acids (FFA) inside mitochondria produces NADH and FADH2, which transfer their electrons to the mitochondrial respiratory chain. The flow of electrons in mitochondrial complexes I, III, and IV is coupled with the extrusion of protons from the mitochondrial matrix into the intermembrane space. When energy is needed, these protons reenter the matrix through ATP synthase, to generate ATP from ADP. The adenine nucleotide translocator (ANT) then exchanges the formed ATP for cytosolic ADP. G-6-P Glucose 6-phosphate, PDH pyruvate dehydrogenase, LCFA-CoA long-chain fatty acyl-CoA, CPTI carnitine palmitoyltransferase I, TCA cycle tricarboxylic acid cycle, c cytochrome c...

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