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 chemical reactions to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins. 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.
In molecular biology, biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined to form macromolecules. This process often consists of metabolic pathways. Some of these biosynthetic pathways are located within a single cellular organelle, while others involve enzymes that are located within multiple cellular organelles. Examples of these biosynthetic pathways include the production of lipid membrane components and nucleotides. Biosynthesis is usually synonymous with anabolism.
N-Acetylglutamate synthase (NAGS) is an enzyme that catalyses the production of N-acetylglutamate (NAG) from glutamate and acetyl-CoA.
In enzymology, a succinate-semialdehyde dehydrogenase (SSADH) (EC 1.2.1.24) is an enzyme that catalyzes the chemical reaction
In enzymology, a succinylglutamate-semialdehyde dehydrogenase (EC 1.2.1.71) is an enzyme that catalyzes the chemical reaction
In enzymology, a succinyl-CoA:(R)-benzylsuccinate CoA-transferase is an enzyme that catalyzes the chemical reaction
In enzymology, an adenosylcobyric acid synthase (glutamine-hydrolysing) (EC 6.3.5.10) is an enzyme that catalyzes the chemical reaction
Cobalt chelatase (EC 6.6.1.2) is an enzyme that catalyzes the chemical reaction
In enzymology, a hydrogenobyrinic acid a,c-diamide synthase (glutamine-hydrolysing) (EC 6.3.5.9) is an enzyme that catalyzes the chemical reaction
In enzymology, 2-aminomuconate deaminase (EC 3.5.99.5) (also known as amnd) is an enzyme that catalyzes the chemical reaction
In enzymology, a N-formylglutamate deformylase (EC 3.5.1.68) is an enzyme that catalyzes the chemical reaction
In enzymology, a N-succinylarginine dihydrolase (EC 3.5.3.23) is an enzyme that catalyzes the chemical reaction
In enzymology, a succinyl-diaminopimelate desuccinylase (EC 3.5.1.18) is an enzyme that catalyzes the chemical reaction
In enzymology, an arginine N-succinyltransferase (EC 2.3.1.109) is an enzyme that catalyzes the chemical reaction
In enzymology, an acetylornithine transaminase (EC 2.6.1.11) is an enzyme that catalyzes the chemical reaction
In enzymology, a diaminobutyrate-2-oxoglutarate transaminase is an enzyme that catalyzes the chemical reaction
In enzymology, a succinylornithine transaminase (EC 2.6.1.81) is an enzyme that catalyzes the chemical reaction
The gabT RNA motif is the name of a conserved RNA structure identified by bioinformatics whose function is unknown. The gabT motif has been detected exclusively in bacteria within the genus Pseudomonas, and is found only upstream of gabT genes, and downstream to gabD genes.
In molecular biology, members of the ArgJ protein family are bifunctional protein that catalyses the first and fifth steps in arginine biosynthesis. The structure has been determined for glutamate N-acetyltransferase 2, an ArgJ-like protein from Streptomyces clavuligerus.
In molecular biology, the arginine repressor (ArgR) is a repressor of prokaryotic arginine deiminase pathways.
