Malate dehydrogenase (decarboxylating)

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NAD-malic enzyme
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malic enzyme tetramer, Human
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EC no. 1.1.1.39
CAS no. 9028-46-0
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Malate dehydrogenase (decarboxylating) (EC 1.1.1.39) or NAD-malic enzyme (NAD-ME) is an enzyme that catalyzes the chemical reaction

(S)-malate + NAD+ pyruvate + CO2 + NADH

Thus, the two substrates of this enzyme are (S)-malate and NAD+, whereas its three products are pyruvate, CO2, and NADH. Malate is oxidized to pyruvate and CO2, and NAD+ is reduced to NADH.

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:NAD+ oxidoreductase (decarboxylating). This enzyme participates in pyruvate metabolism and carbon fixation. NAD-malic enzyme is one of three decarboxylation enzymes used in the inorganic carbon concentrating mechanisms of C4 and CAM plants. The others are NADP-malic enzyme and PEP carboxykinase. [1] [2]

Related Research Articles

<span class="mw-page-title-main">Citric acid cycle</span> Interconnected biochemical reactions releasing energy

The citric acid cycle—also known as the Krebs cycle, Szent–Györgyi–Krebs cycle or the TCA cycle (tricarboxylic acid cycle)—is a series of biochemical reactions to release the energy stored in nutrients through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins. The chemical energy released is available under the form of ATP. The Krebs cycle is used by organisms that respire (as opposed to organisms that ferment) to generate energy, either by anaerobic respiration or aerobic respiration. In addition, the cycle provides precursors of certain amino acids, as well as the reducing agent NADH, that are used in numerous other reactions. Its central importance to many biochemical pathways suggests that it was one of the earliest components of metabolism. Even though it is branded as a "cycle", it is not necessary for metabolites to follow only one specific route; at least three alternative segments of the citric acid cycle have been recognized.

<span class="mw-page-title-main">Glycolysis</span> Series of interconnected biochemical reactions

Glycolysis is the metabolic pathway that converts glucose into pyruvate and, in most organisms, occurs in the liquid part of cells. The free energy released in this process is used to form the high-energy molecules adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide (NADH). Glycolysis is a sequence of ten reactions catalyzed by enzymes.

A dehydrogenase is an enzyme belonging to the group of oxidoreductases that oxidizes a substrate by reducing an electron acceptor, usually NAD+/NADP+ or a flavin coenzyme such as FAD or FMN. Like all catalysts, they catalyze reverse as well as forward reactions, and in some cases this has physiological significance: for example, alcohol dehydrogenase catalyzes the oxidation of ethanol to acetaldehyde in animals, but in yeast it catalyzes the production of ethanol from acetaldehyde.

<span class="mw-page-title-main">Crassulacean acid metabolism</span> Metabolic process

Crassulacean acid metabolism, also known as CAM photosynthesis, is a carbon fixation pathway that evolved in some plants as an adaptation to arid conditions that allows a plant to photosynthesize during the day, but only exchange gases at night. In a plant using full CAM, the stomata in the leaves remain shut during the day to reduce evapotranspiration, but they open at night to collect carbon dioxide and allow it to diffuse into the mesophyll cells. The CO2 is stored as four-carbon malic acid in vacuoles at night, and then in the daytime, the malate is transported to chloroplasts where it is converted back to CO2, which is then used during photosynthesis. The pre-collected CO2 is concentrated around the enzyme RuBisCO, increasing photosynthetic efficiency. This mechanism of acid metabolism was first discovered in plants of the family Crassulaceae.

C<sub>4</sub> carbon fixation Photosynthetic process in some plants

C4 carbon fixation or the Hatch–Slack pathway is one of three known photosynthetic processes of carbon fixation in plants. It owes the names to the 1960s discovery by Marshall Davidson Hatch and Charles Roger Slack.

<span class="mw-page-title-main">Isocitrate dehydrogenase</span> Class of enzymes

Isocitrate dehydrogenase (IDH) (EC 1.1.1.42) and (EC 1.1.1.41) is an enzyme that catalyzes the oxidative decarboxylation of isocitrate, producing alpha-ketoglutarate (α-ketoglutarate) and CO2. This is a two-step process, which involves oxidation of isocitrate (a secondary alcohol) to oxalosuccinate (a ketone), followed by the decarboxylation of the carboxyl group beta to the ketone, forming alpha-ketoglutarate. In humans, IDH exists in three isoforms: IDH3 catalyzes the third step of the citric acid cycle while converting NAD+ to NADH in the mitochondria. The isoforms IDH1 and IDH2 catalyze the same reaction outside the context of the citric acid cycle and use NADP+ as a cofactor instead of NAD+. They localize to the cytosol as well as the mitochondrion and peroxisome.

Oxidative decarboxylation is a decarboxylation reaction caused by oxidation. Most are accompanied by α- Ketoglutarate α- Decarboxylation caused by dehydrogenation of hydroxyl carboxylic acids such as carbonyl carboxylic acid, malic acid, isocitric acid, etc.

In enzymology, a D-malate dehydrogenase (decarboxylating) (EC 1.1.1.83) is an enzyme that catalyzes the chemical reaction

<span class="mw-page-title-main">Homoisocitrate dehydrogenase</span> Enzyme

In enzymology, a homoisocitrate dehydrogenase (EC 1.1.1.87) is an enzyme that catalyzes the chemical reaction

Malate dehydrogenase (NADP<sup>+</sup>)

In enzymology, a malate dehydrogenase (NADP+) (EC 1.1.1.82) is an enzyme that catalyzes the chemical reaction

<span class="mw-page-title-main">Malate dehydrogenase (oxaloacetate-decarboxylating)</span>

In enzymology, a malate dehydrogenase (oxaloacetate-decarboxylating) (EC 1.1.1.38) is an enzyme that catalyzes the chemical reaction below

Malate dehydrogenase (oxaloacetate-decarboxylating) (NADP<sup>+</sup>) Enzyme

Malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+) (EC 1.1.1.40) or NADP-malic enzyme (NADP-ME) is an enzyme that catalyzes the chemical reaction in the presence of a bivalent metal ion:

In enzymology, an oxaloglycolate reductase (decarboxylating) (EC 1.1.1.92) is an enzyme that catalyzes the chemical reaction

In enzymology, a sterol-4alpha-carboxylate 3-dehydrogenase (decarboxylating) (EC 1.1.1.170) is an enzyme that catalyzes the chemical reaction

In enzymology, a 1,6-dihydroxycyclohexa-2,4-diene-1-carboxylate dehydrogenase (EC 1.3.1.25) is an enzyme that catalyzes the chemical reaction

In enzymology, an arogenate dehydrogenase [NAD(P)+] (EC 1.3.1.79) is an enzyme that catalyzes the chemical reaction

In enzymology, a 4-hydroxybenzoate 1-hydroxylase (EC 1.14.13.64) is an enzyme that catalyzes the chemical reaction

In enzymology, an anthranilate 1,2-dioxygenase (deaminating, decarboxylating) (EC 1.14.12.1) is an enzyme that catalyzes the chemical reaction

In enzymology, a 2-oxoaldehyde dehydrogenase (NAD+) (EC 1.2.1.23) is an enzyme that catalyzes the chemical reaction

In enzymology, a malonate-semialdehyde dehydrogenase (acetylating) (EC 1.2.1.18) is an enzyme that catalyzes the chemical reaction

References

  1. Kanai R, Edwards, GE (1999). "3. The Biochemistry of C4 Photosynthesis". In Sage RF, Monson RK (eds.). C4 Plant Biology. pp. 43–87. ISBN   0126144400.
  2. Christopher JT, Holtum JA (1996). "Patterns of carbon partitioning in leaves of Crassulacean acid metabolism species during deacidification". Plant Physiol. 112 (1): 393–399. doi:10.1104/pp.112.1.393. PMC   157961 . PMID   12226397.