What does the malic enzyme do?
Malic enzyme (ME) is widespread in all kinds of organisms and catalyzes the reversible oxidative decarboxylation of malate to pyruvate, CO2, and NAD(P)H in the presence of a divalent metal ion (Drincovich et al., 2001).
What enzyme converts malate to pyruvate?
malic enzyme
Pyruvate cycling has been implicated in glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells. The operation of some pyruvate cycling pathways is proposed to necessitate malate export from the mitochondria and NADP+-dependent decarboxylation of malate to pyruvate by cytosolic malic enzyme (ME1).
Does malic enzyme generate Nadph?
Malic enzyme (ME; NADP(+)-dependent; EC 1.1. 40) provides NADPH for lipid biosynthesis in oleaginous microorganisms. However, the availability of cytosolic NADH is limited and, consequently, ancillary means of producing NADPH are necessary.
Is malic enzyme the same as malate dehydrogenase?
Malic enzyme may refer to decarboxylating malate dehydrogenases: Malate dehydrogenase (decarboxylating) (EC 1.1. 1.39) or NAD-malic enzyme. Malate dehydrogenase (oxaloacetate-decarboxylating) (EC 1.1.
Where is malic enzyme found?
In human liver, almost 90% of malic enzyme activity is located within the extramitochondrial compartment, and only approximately 10% in the mitochondrial fraction.
What is the role of malate dehydrogenase in gluconeogenesis?
Malate dehydrogenase is also involved in gluconeogenesis, the synthesis of glucose from smaller molecules. In order to get the oxaloacetate out of the mitochondria, malate dehydrogenase reduces it to malate, and it then traverses the inner mitochondrial membrane.
How is malate converted to pyruvate?
Malate can then either be recycled to pyruvate via the mitochondrial, NAD-dependent form of malic enzyme (MEm) or can be transported to the cytosol via the dicarboxylate carrier (DIC). If transported to the cytosol, malate can be reconverted to pyruvate by the cytosolic, NADP-dependent form of ME (MEc).
Does malate dehydrogenase make Nadph?
Thus, the two substrates of this enzyme are (S)-malate and NADP+, whereas its 3 products are pyruvate, CO2, and NADPH. Malate is oxidized to pyruvate and CO2, and NADP+ is reduced to NADPH….Malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+)
| NADP-malic enzyme | |
|---|---|
| Identifiers | |
| Gene Ontology | AmiGO / QuickGO |
| showSearch |
Does malate dehydrogenase make NADPH?
What is the km of malate dehydrogenase?
Km (oxaloacetate) of commercially available mitochondrial malate dehydrogenase from pig heart was determined as Km equals 1.65 x 10(-5) mol/1 using the measurement conditions for aspartate aminotransferase according to the preliminary recommendations of the IFCC.
Do humans have malic enzyme?
In human liver, almost 90% of malic enzyme activity is located within the extramitochondrial compartment, and only approximately 10% in the mitochondrial fraction. The isoelectric point of the isolated enzyme was 5.65. The enzyme was shown to carboxylate pyruvate with at least the same rate as the forward reaction.
Where is NADH produced by the malic enzyme?
This malate diffuses into the bundle sheath cells, is taken up by the mitochondria, and is oxidized there by malic enzyme to yield NADH. ATP is generated from oxidation of this NADH by the respiratory chain. This pathway also operates in the phosphoenolpyruvate carboxykinase type metabolism.
What is the function of the malic enzyme?
Malic enzymes catalyze the oxidative decarboxylation of malate to pyruvate and CO2, with the concomitant reduction of the cofactor NAD(P)+ to NAD(P)H.
How is malic acid converted to lactic acid?
The malic enzyme is NAD dependent; it acts together with l -lactate dehydrogenase. At the end of the reaction, malic acid is converted to l -malate decarboxylase in lactic acid and CO 2 in the presence of NAD and Mn 2 +. Malic enzyme is produced when microorganisms use malic acid as a source of energy.
What kind of organic acid inhibits NADP-ME enzyme?
The enzyme requires Mg 2+ or Mn 2+. Organic acids also modulate the activity of NADP-ME. Glyoxylate, oxaloacetate, and 2-oxoglutarate inhibit the activity of the maize enzyme, and inhibition is more evident at the lower pH ( Asami et al., 1979; see also Iglesias and Andreo, 1989 ).