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.
The green sulfur bacteria are a phylum, Chlorobiota, of obligately anaerobic photoautotrophic bacteria that metabolize sulfur.
Oxaloacetic acid (also known as oxalacetic acid or OAA) is a crystalline organic compound with the chemical formula HO2CC(O)CH2CO2H. Oxaloacetic acid, in the form of its conjugate base oxaloacetate, is a metabolic intermediate in many processes that occur in animals. It takes part in gluconeogenesis, the urea cycle, the glyoxylate cycle, amino acid synthesis, fatty acid synthesis and the citric acid cycle.
In the mitochondrion, the matrix is the space within the inner membrane. The word "matrix" stems from the fact that this space is viscous, compared to the relatively aqueous cytoplasm. The mitochondrial matrix contains the mitochondrial DNA, ribosomes, soluble enzymes, small organic molecules, nucleotide cofactors, and inorganic ions.[1] The enzymes in the matrix facilitate reactions responsible for the production of ATP, such as the citric acid cycle, oxidative phosphorylation, oxidation of pyruvate, and the beta oxidation of fatty acids.
Pyrococcus furiosus is a heterotrophic, strictly anaerobic, extremophilic, model species of archaea. It is classified as a hyperthermophile because it thrives best under extremely high temperatures, and is notable for having an optimum growth temperature of 100 °C. P. furiosus belongs to the Pyrococcus genus, most commonly found in extreme environmental conditions of hydrothermal vents. It is one of the few prokaryotic organisms that has enzymes containing tungsten, an element rarely found in biological molecules.
Pyruvate dehydrogenase (NADP+) EC 1.2.1.51 is an enzyme that should not be confused with Pyruvate dehydrogenase (acetyltransferase) EC 1.2.4.1.
Pyruvate dehydrogenase is an enzyme that catalyzes the reaction of pyruvate and a lipoamide to give the acetylated dihydrolipoamide and carbon dioxide. The conversion requires the coenzyme thiamine pyrophosphate.
In biochemistry, fatty acid synthesis is the creation of fatty acids from acetyl-CoA and NADPH through the action of enzymes called fatty acid synthases. This process takes place in the cytoplasm of the cell. Most of the acetyl-CoA which is converted into fatty acids is derived from carbohydrates via the glycolytic pathway. The glycolytic pathway also provides the glycerol with which three fatty acids can combine to form triglycerides, the final product of the lipogenic process. When only two fatty acids combine with glycerol and the third alcohol group is phosphorylated with a group such as phosphatidylcholine, a phospholipid is formed. Phospholipids form the bulk of the lipid bilayers that make up cell membranes and surrounds the organelles within the cells. In addition to cytosolic fatty acid synthesis, there is also mitochondrial fatty acid synthesis (mtFASII), in which malonyl-CoA is formed from malonic acid with the help of malonyl-CoA synthetase (ACSF3), which then becomes the final product octanoyl-ACP (C8) via further intermediate steps.
In enzymology, an indolepyruvate C-methyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, a 2-oxoglutarate synthase (EC 1.2.7.3) is an enzyme that catalyzes the chemical reaction
In enzymology, a 3-methyl-2-oxobutanoate dehydrogenase (ferredoxin) (EC 1.2.7.7) is an enzyme that catalyzes the chemical reaction
In enzymology, a carbon-monoxide dehydrogenase (ferredoxin) (EC 1.2.7.4) is an enzyme that catalyzes the chemical reaction
In enzymology, a glyceraldehyde-3-phosphate dehydrogenase (ferredoxin) (EC 1.2.7.6) is an enzyme that catalyzes the chemical reaction
In enzymology, a pyruvate synthase is an enzyme that catalyzes the interconversion of pyruvate and acetyl-CoA. It is also called pyruvate:ferredoxin oxidoreductase (PFOR).
In enzymology, a rubredoxin—NAD(P)+ reductase (EC 1.18.1.4) is an enzyme that catalyzes the chemical reaction
The enzyme indolepyruvate decarboxylase (EC 4.1.1.74) catalyzes the chemical reaction
In enzymology, a pyruvate, water dikinase (EC 2.7.9.2) is an enzyme that catalyzes the chemical reaction
Indole-3-pyruvate monooxygenase (EC 1.14.13.168, YUC2 (gene), spi1 (gene)) is an enzyme with systematic name indole-3-pyruvate,NADPH:oxygen oxidoreductase (1-hydroxylating, decarboxylating). This enzyme catalyses the following chemical reaction
In enzymology, an aldehyde ferredoxin oxidoreductase (EC 1.2.7.5) is an enzyme that catalyzes the chemical reaction
Pyruvate decarboxylation or pyruvate oxidation, also known as the link reaction, is the conversion of pyruvate into acetyl-CoA by the enzyme complex pyruvate dehydrogenase complex.
