malic enzyme


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malic enzyme

[′mal·ik ′en‚zīm]
(biochemistry)
An enzyme which utilizes nicotinamide-adenine dinucleotide phosphate (NADP) to catalyze the oxidative decarboxylation of malic acid to pyruvic acid and carbon dioxide. Also known as malate dehydrogenase.
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Spectrophotometric assays were used to determine the activity of glucose 6-phosphate dehydrogenase (G6PDH) [16], isocitrate dehydrogenase (ICDH) [17], malate dehydrogenase (MDH) [18], and malic enzyme (ME) [19].
In this case, the lack of malic enzyme increases malate accumulation and diminishes the formation of pyruvate and of ethanol, which is highly toxic to plants.
The team overexpressed an additional bacterialgene in this strain to produce malic enzyme. They combined strategy resulted in an improvement of 25 percent over previously engineered yeasts.
Ten enzyme systems in starch gel were analyzed: Aspartate amino Transferase (AAT), Alcohol Dehydrogenase (ADH), Glucose-3-phosphate dehydrogenase (G3PD), Glucose-6-phosphate dehydrogenase (G6PD), Glucose phosphate Isomerase (GPI), Isocitrate Dehydrogenase (IDH), Lactate dehydrogenase (LDH), Malate dehydrogenase (MDH) Malic Enzyme (ME), Phosphoglucomutase (PGM), and Esterase (EST) in the polyacrylamide gel.
One approach is to transform the key genes for C4 photosynthesis enzymes, such as PEP carboxylase (PEPC) (Hudspeth et al., 1992; Ku et al., 1999; Endo et al., 2008), NADP malic enzyme (NADP-ME) (Takeuchi et al., 2000; Tsuchida et al., 2001) and pyruvate orthophosphate dikinase (Fukayama et al., 2001; Wang et al., 2012) into C3 plants.
Saccharomyces cerevisiae-derived peptides reduce the activity of enzymes critical to the manufacture of fat from excess energy in foods, particularly glucose-6-phosphate dehydrogenase (G6PD) and malic enzyme (ME).
Acetyl-CoA can be used as the carbon source for fatty acid synthesis and oxaloacetate can be converted by malic enzyme 1 to pyruvate that then reenters mitochondria.
This MDH then undergoes oxidative decarboxylation to form pyruvate and C[O.sub.2], while generating NADPH from [NADP.sup.+] in a reaction catalyzed by malic enzyme. Reuptake of pyruvate by mitochondria occurs, whereby pyruvate combines with CO2 to regenerate oxaloacetate in a reaction catalyzed by the enzyme pyruvate carboxylase.
Abbreviations PUFAs: Polyunsaturated fatty acids SCO: Single cell oil GLA: [gamma]-linolenic acid AA: Arachidonic acid NADPH: Nicotinamide adenine dinucleotide phosphate AMP: Adenosine monophosphate Acetyl Co-A: Acetyl co-enzyme A ME: Malic enzyme FAS: Fatty acid synthase ACL: ATP citrate-lyase NAD: ICDH: Nicotinamide adenine dinucleotide: isocitrate dehydrogenase N: Nitrogen C: Carbon X: Biomass (g/L) L: Lipid.
Genes relevantes sobre expresados en IB GEN ENTREZ GENE NAME FOLD CHANGE CASP 7 Caspase 7 2,02 ME1 Malic Enzyme 2,00 UBE2D4 Ubiquitin conjugating 1,57 enzyme ELOVL6 Fatty Acid Elongase 6 1,56 CASP4 Caspase 4 1,56 CTSL2 Cathepsin L2 1,44 Genes relevantes sobre expresados en DU x IB IGF2 Insuline-like ggrowth factor 2 -4,87 COL12A1 Collagen type XII alpha 1 -2,61 COL1A1 Collagen type I alpha 1 -2,17 UBA5 Ubiquitin-like modifier act.
It has been demonstrated that the cytosolic NAD (P)- dependent dehydrogenases6 and NADP malic enzyme are inhibited by MTX, indicating that the drug could decrease the availability of NADPH in cells by inhibiting pentose cycle enzymes.7 Due to the interference with the pentose phosphate shunt, MTX may also depress nucleic acid metabolism.