Citric Acid Cycle

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[[Image:2000px-Glycolysis.png|350px|right|thumb| Overview of Each Step of Glycolysis]]
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<StructureSection load='1cts' size='350' side='right' scene='User:Wayne_Decatur/1cts_to_2cts_(citrate_synthase)_morph_methods/Camorph/5' caption='Open conformation of citrate synthase dimer complex with citrate (PDB code [[1cts]]) and closed conformation of citrate synthase dimer complex with citrate and CoA (PDB code [[2cts]])'>
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The [[Citric Acid Cycle]]
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[[Image:Citric acid cycle with aconitate 2.png|350px|left|thumb| A Citric Acid Cycle Schematic]]
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{{Clear}}
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'''The Citric Acid Cycle is a key metabolic pathway that connects carbohydrate, fat, and protein metabolism!!!''' See also [https://en.wikipedia.org/wiki/Citric_acid_cycle].
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*[[Krebs cycle importance]]
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*[[Krebs cycle overview]]
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*[[Krebs cycle reactions]]
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*[[Major metabolic pathways converging on the citric acid cycle]]
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*[[Citric acid cycle intermediates serve as substrates for biosynthetic processes]]
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The [[Citric Acid Cycle]] (tricarboxylic acid cycle) is a series of enzyme catalyzed reactions which are critical in cellular respiration. Under oxidative conditions, pyruvate continues to be metabolized through the tricarboxylic acid cycle. In this cycle, Acetyl-CoA, a byproduct of [[glycolysis]], along with various cofactors, are broken down into carbon dioxide, water, and energy in the form of GTP and NADH.
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Articles in Proteopedia concerning [[Citric Acid Cycle]] include:
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'''Pyruvate decarboxylation or pyruvate oxidation''', also known as the link reaction (or oxidative decarboxylation of pyruvate), is the conversion of <scene name='39/392339/Cv1/11'>pyruvate</scene> into <scene name='43/430893/Cv/2'>Acetyl-CoA</scene> by the enzyme complex pyruvate dehydrogenase complex (see [[Pyruvate dehydrogenase]]).
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* [[2-Oxoglutarate Dehydrogenase]]
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The multienzyme complex together catalyzes five distinct reactions in the conversion of pyruvate to Acetyl-CoA. The overall result is described by the following reaction:
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Pyruvate + CoA + NAD+ ==> Acetyl-CoA + CO2 + NADH
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However, pyruvate dehydrogenase (E1) is responsible for only the first two of the five reactions. The first of these is the decarboxylation of pyruvate and coupling of thiamine pyrophosphate (TPP) to form hydroxyethyl-TPP.
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Pyruvate + TPP ==> Hydroxyethyl-TPP + CO2
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''' Step 0 / 10 - Aldol condensation - Citrate synthase'''
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*[[Citrate Synthase]]
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*Step 0 / 10 = [[Krebs cycle step 1]]
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*[[ATP-citrate synthase]]
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4C <scene name='43/430893/Cv/3'>oxaloacetate</scene> to a 6C molecule <scene name='43/430893/Cv/4'>citrate</scene>
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'''Step 1 - Dehydration - Aconitase'''
* [[Aconitase]]
* [[Aconitase]]
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* [[Citrate_Synthase|Citrate Synthase Structure & Mechanism]]
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*1st step of [[Krebs cycle step 2]]
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* [[User:Cameron Evans/Sandbox 1|Glutamate Dehydrogenase]]
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6C Citrate => 6C <scene name='43/430893/Cv/5'>cis-Aconitate</scene>
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* [[Malate dehydrogenase|Malate Dehydrogenase]]
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* [[Succinyl-Coa Synthetase]]
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<br/>
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To view [[Citric Acid Cycle]] related proteins which are [[Proteopedia:Structure Index|Structure Index]] entries see:
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'''Step 2 - Hydration - Aconitase'''
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* [[Aconitase#Available_3D_structures_of_Aconitase|Aconitase]]
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* [[Aconitase]]
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*2nd step of [[Krebs cycle step 2]]
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6C ''cis''-Aconitate => 6C <scene name='43/430893/Cv/6'>Isocitrate</scene>
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'''Step 3 - Oxidation - Isocitrate dehydrogenase'''
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*[[Isocitrate dehydrogenase]]
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*1st step of [[Krebs cycle step 3]]
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6C Isocitrate => 6C <scene name='43/430893/Cv/7'>Oxalosuccinate</scene>
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To view automatically seeded indices concerning [[Citric Acid Cycle] See:
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'''Step 4 - Decarboxylation - Isocitrate dehydrogenase'''
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*[[Isocitrate dehydrogenase]]
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*2nd step of [[Krebs cycle step 3]]
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6C Oxalosuccinate => 5C <scene name='43/430893/Cv/8'>α-Ketoglutarate</scene>
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The α-ketoglutarate family of amino acid synthesis (synthesis of glutamate, glutamine, proline and arginine) begins with α-ketoglutarate, an intermediate in the Citric Acid Cycle. See [[Alpha-Ketoglutarates: glutamate, glutamine, proline, arginine]]
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'''Step 5 - Oxidative decarboxylation - α-Ketoglutarate dehydrogenase (2-Oxoglutarate Dehydrogenase)'''
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*[[2-Oxoglutarate Dehydrogenase]]
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*Step 5 = [[Krebs cycle step 4]]
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5C α-Ketoglutarate => <scene name='43/430893/Cv/9'>Succinyl-CoA</scene> 4C chain (CoA excluded)
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'''Step 6 - Substrate-level phosphorylation - Succinyl-CoA synthetase'''
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*[[Succinyl-CoA synthetase]]
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*Step 6 = [[Krebs cycle step 5]]
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Succinyl-CoA => <scene name='43/430893/Cv/10'>Succinate</scene>
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The succinyl-CoA formed during [[Beta oxidation]] can also enter the Citric Acid Cycle in this step.
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'''Step 7 - Oxidation - Succinate dehydrogenase'''
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*[[Succinate Dehydrogenase]]
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*Step 7 = [[Krebs cycle step 6]]
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Succinate => <scene name='43/430893/Cv/11'>Fumarate</scene>
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'''Step 8 - Hydration - Fumarase'''
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*[[Fumarase]]
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*Step 8 = [[Krebs cycle step 7]]
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Fumarate => <scene name='43/430893/Cv/12'>L-Malate</scene>
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'''Step 9 - Oxidation - Malate dehydrogenase'''
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*[[Malate dehydrogenase]]
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*Step 9 = [[Krebs cycle step 8]]
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L-Malate => <scene name='43/430893/Cv/3'>oxaloacetate</scene>
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Oxaloacetate takes part in [[gluconeogenesis]], the urea cycle, the glyoxylate cycle, amino acid synthesis ([[Oxaloacetate/aspartate: lysine, asparagine, methionine, threonine, and isoleucine]]), [[fatty acid synthesis]].
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'''Step 10 / 0 - Aldol condensation - Citrate synthase'''
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*[[Citrate Synthase]]
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*Step 10 / 0 = [[Krebs cycle step 1]]
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4C <scene name='43/430893/Cv/3'>oxaloacetate</scene> to a 6C molecule <scene name='43/430893/Cv/4'>citrate</scene>
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To view automatically seeded indices concerning [[Citric Acid Cycle]] See:
*[[:Category:Citric acid cycle|Citric Acid Cycle]]
*[[:Category:Citric acid cycle|Citric Acid Cycle]]
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*[[:Category:Citric acid cycle|Krebs Cycle]]
 
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See also:
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*[[Biosynthesis of cholesterol]]
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*[[Fatty acid synthesis]]
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*[[Amino Acid Synthesis]]
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</StructureSection>

Current revision

Open conformation of citrate synthase dimer complex with citrate (PDB code 1cts) and closed conformation of citrate synthase dimer complex with citrate and CoA (PDB code 2cts)

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Proteopedia Page Contributors and Editors (what is this?)

Alexander Berchansky, David Canner, Ann Taylor, Wayne Decatur, Jaime Prilusky

Retrieved from "http://52.214.119.220/wiki/index.php/Citric_Acid_Cycle"
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