Citric acid cycle
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Overview of the citric acid cycle
The citric acid cycle — also known as the tricarboxylic acid cycle (TCA cycle), the Krebs cycle, or the Szent-Györgyi-Krebs cycle, [1][2] — is a series of enzyme-catalysed chemical reactions, which is of central importance in all living cells that use oxygen as part of cellular respiration. In eukaryotic cells, the citric acid cycle occurs in the matrix of the mitochondrion. The components and reactions of the citric acid cycle were established by seminal work from Albert Szent-Györgyi and Hans Krebs.
In aerobic organisms, the citric acid cycle is part of a metabolic pathway involved in the chemical conversion …show more content…

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| | |CO2 | | |generates a 5C molecule |
|6 |α-Ketoglutarate + |Succinyl-CoA + |α-Ketoglutarate |Oxidative |irreversible stage, |
| |NAD+ + |NADH + H+ + |dehydrogenase |decarboxylation |generates NADH (equivalent of 2.5 |
| |CoA-SH |CO2 | | |ATP), |
| | | | | |regenerates the 4C chain (CoA |
| | | | | |excluded) |
|7 |Succinyl-CoA + |Succinate + |Succinyl-CoA |substrate-level |or ADP→ATP instead of GDP→GTP,[4] |
| |GDP + Pi |CoA-SH + |synthetase |phosphorylation |generates 1 ATP or equivalent |
| | |GTP | | | |
|8 |Succinate + |Fumarate + |Succinate |Oxidation |uses FAD as a prosthetic group |
| |ubiquinone (Q) |ubiquinol (QH2) |dehydrogenase | |(FAD→FADH2 in the first step of the|
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