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Malate is oxidized to pyruvate and CO 2, and NADP + is reduced to NADPH. This enzyme belongs to the family of oxidoreductases, to be specific those acting on the CH-OH group of donor with NAD + or NADP + as acceptor. The systematic name of this enzyme class is (S)-malate:NADP + oxidoreductase (oxaloacetate-decarboxylating). This enzyme ...
The ratio of NADPH:NADP + is the primary mode of regulation for the enzyme and is normally about 100:1 in liver cytosol [citation needed]. This makes the cytosol a highly-reducing environment. An NADPH-utilizing pathway forms NADP +, which stimulates Glucose-6-phosphate dehydrogenase to produce more NADPH.
The source of the NADPH is two-fold. When malate is oxidatively decarboxylated by "NADP +-linked malic enzyme" pyruvate, CO 2 and NADPH are formed. NADPH is also formed by the pentose phosphate pathway which converts glucose into ribose, which can be used in synthesis of nucleotides and nucleic acids, or it can be catabolized to pyruvate. [50]
The source of the NADPH is two-fold. When malate is oxidatively decarboxylated by "NADP +-linked malic enzyme" to form pyruvate, CO 2 and NADPH are formed. NADPH is also formed by the pentose phosphate pathway which converts glucose into ribose, which can be used in synthesis of nucleotides and nucleic acids, or it can be catabolized to ...
In rat liver, the total amount of NAD + and NADH is approximately 1 μmole per gram of wet weight, about 10 times the concentration of NADP + and NADPH in the same cells. [17] The actual concentration of NAD + in cell cytosol is harder to measure, with recent estimates in animal cells ranging around 0.3 mM , [ 18 ] [ 19 ] and approximately 1.0 ...
Pyruvate + 2 H + + 2 e − → Lactate-0.19 [9] Oxaloacetate + 2 H + + 2 e − → Malate-0.17 [10] While under standard conditions malate cannot reduce the more electronegative NAD +:NADH couple, in the cell the concentration of oxaloacetate is kept low enough that Malate dehydrogenase can reduce NAD + to NADH during the citric acid cycle.
Pyruvate is the terminal electron acceptor in lactic acid fermentation. When sufficient oxygen is not present in the muscle cells for further oxidation of pyruvate and NADH produced in glycolysis, NAD+ is regenerated from NADH by reduction of pyruvate to lactate. [4] Lactate is converted to pyruvate by the enzyme lactate dehydrogenase. [3]
Malate dehydrogenase (EC 1.1.1.37) (MDH) is an enzyme that reversibly catalyzes the oxidation of malate to oxaloacetate using the reduction of NAD + to NADH. This reaction is part of many metabolic pathways, including the citric acid cycle.