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| :::::'''[[citrate]] <big>→</big> [[Aconitic acid|cis-aconitate]] <big>→</big> α-ketoglutarate <big>→</big> [[succinyl-CoA]] <big>→</big> [[succinate]] <big>→</big> [[Fumaric acid|fumarate]] <big>→</big> [[malate]] <big>→</big> [[oxaloacetate]] <big>→</big> [[citrate]]''' | :::::'''[[citrate]] <big>→</big> [[Aconitic acid|cis-aconitate]] <big>→</big> α-ketoglutarate <big>→</big> [[succinyl-CoA]] <big>→</big> [[succinate]] <big>→</big> [[Fumaric acid|fumarate]] <big>→</big> [[malate]] <big>→</big> [[oxaloacetate]] <big>→</big> [[citrate]]''' |
| In this cycle, the enzyme [[isocitrate dehydrogenase]] converts D-isocitrate to α-ketoglutarate which in the next step is converted to succinyl-CoA by the enxyme complex, [[oxoglutarate dehydrogenase complex]]. Outside of the citric acid cycle, α-ketoglutarate is made by '''a)''' the enzyme [[isocitrate dehydrogenase]]'s oxidative [[decarboxylation]] (i.e., removal of a carboxy group) from [[isocitrate]]; '''b)''' the enzyme [[glutamate dehydrogenase]]'s oxidative [[deamination]], i.e., removal of the [[amino group]] (i.e., {{chem2|\sNH2}}) from [[glutamate]] and '''c)''' various [[pyridoxal phosphate]]-dependent transamination reactions (e.g., [[alanine transaminase]], also termed alanine aminotransferase and glutamate pyruvate transaminase<ref name="pmid19085960">{{cite journal | vauthors = Yang RZ, Park S, Reagan WJ, Goldstein R, Zhong S, Lawton M, Rajamohan F, Qian K, Liu L, Gong DW | title = Alanine aminotransferase isoenzymes: molecular cloning and quantitative analysis of tissue expression in rats and serum elevation in liver toxicity | journal = Hepatology (Baltimore, Md.) | volume = 49 | issue = 2 | pages = 598–607 | date = February 2009 | pmid = 19085960 | pmc = 2917112 | doi = 10.1002/hep.22657 | url = }}</ref>) in which glutamate "donates" its amino group to other substances (see [[transamination]]).<ref name="pmid26759695"/><ref name="pmid34952764">{{cite journal | vauthors = Gyanwali B, Lim ZX, Soh J, Lim C, Guan SP, Goh J, Maier AB, Kennedy BK | title = Alpha-Ketoglutarate dietary supplementation to improve health in humans | journal = Trends in Endocrinology and Metabolism: TEM | volume = 33 | issue = 2 | pages = 136–146 | date = February 2022 | pmid = 34952764 | doi = 10.1016/j.tem.2021.11.003 | url = }}</ref> Acting in these pathwasys, α-ketoglutaratehas functions in: | In this cycle, the [[enzyme]] [[isocitrate dehydrogenase]] converts D-isocitrate to α-ketoglutarate which in the next step is converted to succinyl-CoA by the [[oxoglutarate dehydrogenase complex]] of enzymes. Outside of the citric acid cycle, α-ketoglutarate is made by '''a)''' the enzyme [[isocitrate dehydrogenase]]'s removal of a carboxy group by oxidative [[decarboxylation]] from [[isocitrate]]; '''b)''' the enzyme [[glutamate dehydrogenase]]'s removal of the [[amino group]], i.e., {{chem2|\sNH2}}, from [[glutamate]], '''c)''' various [[pyridoxal phosphate]]-dependent transamination reactions by e.g., [[alanine transaminase]]<ref name="pmid19085960">{{cite journal | vauthors = Yang RZ, Park S, Reagan WJ, Goldstein R, Zhong S, Lawton M, Rajamohan F, Qian K, Liu L, Gong DW | title = Alanine aminotransferase isoenzymes: molecular cloning and quantitative analysis of tissue expression in rats and serum elevation in liver toxicity | journal = Hepatology (Baltimore, Md.) | volume = 49 | issue = 2 | pages = 598–607 | date = February 2009 | pmid = 19085960 | pmc = 2917112 | doi = 10.1002/hep.22657 | url = }}</ref>) in which glutamate "donates" its amino group to other substances (see [[transamination]]).<ref name="pmid26759695"/><ref name="pmid34952764">{{cite journal | vauthors = Gyanwali B, Lim ZX, Soh J, Lim C, Guan SP, Goh J, Maier AB, Kennedy BK | title = Alpha-Ketoglutarate dietary supplementation to improve health in humans | journal = Trends in Endocrinology and Metabolism: TEM | volume = 33 | issue = 2 | pages = 136–146 | date = February 2022 | pmid = 34952764 | doi = 10.1016/j.tem.2021.11.003 | url = }}</ref> Acting in these pathwasys, α-ketoglutaratehas functions to promote the formation of [[amino acids]], such as [[glutamine]], [[proline]], [[arginine]], and [[lysine]]. This in turn contributes to the regulation of cellular carbon and nitrogen usage and thereby prevents excessive levels of these two elements from accumulating in tissues.<ref name="pmid19085960"/><ref name="pmid34952764"/><ref name="pmid29750149">{{cite journal | vauthors = Liu S, He L, Yao K | title = The Antioxidative Function of Alpha-Ketoglutarate and Its Applications | journal = BioMed Research International | volume = 2018 | issue = | pages = 3408467 | date = 2018 | pmid = 29750149 | pmc = 5884300 | doi = 10.1155/2018/3408467 | url = }}</ref> For example, the amino groups of amino acids are transferred to α-ketoglutarate which is then carried to the liver where its amino groups are added to the [[urea cycle]] and removed as [[urea]] from the body.<ref>{{Cite journal |last=Katayama |first=Kazuhiro |date=2004-12-01 |title=Ammonia metabolism and hepatic encephalopathy |url=https://www.sciencedirect.com/science/article/pii/S138663460400227X |journal=Hepatology Research |volume=30 |pages=73–80 |doi=10.1016/j.hepres.2004.08.013 |pmid=15607143 |issn=1386-6346}}</ref> |
| :'''1)''' The formation of [[amino acids]], such as [[glutamine]], [[proline]], [[arginine]], and [[lysine]] which in turn contributes to the regulation of cellular carbon and nitrogen usage and and preventing the overload of these elements.<ref name="pmid19085960"/><ref name="pmid34952764"/><ref name="pmid29750149">{{cite journal | vauthors = Liu S, He L, Yao K | title = The Antioxidative Function of Alpha-Ketoglutarate and Its Applications | journal = BioMed Research International | volume = 2018 | issue = | pages = 3408467 | date = 2018 | pmid = 29750149 | pmc = 5884300 | doi = 10.1155/2018/3408467 | url = }}</ref> For example, the amino groups of amino acids are transferred to α-ketoglutarate which is then carried to the liver where its amino groups are added to the [[urea cycle]] and removed as [[urea]] from the body.<ref>{{Cite journal |last=Katayama |first=Kazuhiro |date=2004-12-01 |title=Ammonia metabolism and hepatic encephalopathy |url=https://www.sciencedirect.com/science/article/pii/S138663460400227X |journal=Hepatology Research |volume=30 |pages=73–80 |doi=10.1016/j.hepres.2004.08.013 |pmid=15607143 |issn=1386-6346}}</ref> | |
| :'''2)''' | |
| ===Nitrogen transporter=== | ===Nitrogen transporter=== |
Okumaya devam et...