|
|Section2= |Section3= }} Acetyl coenzyme A or acetyl-CoA is an important molecule in metabolism, used in many biochemical reactions. Its main function is to convey the carbon atoms within the acetyl group to the citric acid cycle (Krebs cycle) to be oxidized for energy production. Structure of coenzyme A (CoASH or CoA) consists of a β-mercaptoethylamine group linked to the vitamin pantothenic acid through an amide linkage. The acetyl group of acetyl-CoA is linked by a "high energy" thioester to the sulfhydryl portion of the β-mercaptoethylamine. It is this thioester bond that makes acetyl-CoA one of the "high energy" compounds. Hydrolysis of the thioester bond is highly exergonic (-31.5 kJ). Acetyl-CoA is produced during breakdown of carbohydrates through glycolysis as well as fatty acid oxidation and enters the citric acid cycle. Acetyl-CoA is also an important component in the biogenic synthesis of the neurotransmitter acetylcholine. Choline, in combination with acetyl-CoA, is catalyzed by the enzyme choline acetyltransferase to produce acetylcholine and a Coenzyme A byproduct. Konrad Bloch and Feodor Lynen were awarded the 1964 Nobel Prize in Physiology and Medicine for their discoveries linking acetyl-CoA and fatty acid metabolism. Fritz Lipmann won the Nobel Prize in 1953 for his discovery of the cofactor Coenzyme A. ==Functions== ===Pyruvate dehydrogenase and pyruvate formate lyase reactions=== The oxidative conversion of pyruvate into acetyl-CoA is referred to as the pyruvate dehydrogenase reaction. It is catalyzed by the pyruvate dehydrogenase complex. Other conversions between pyruvate and acetyl-CoA are possible. For example, pyruvate formate lyase disproportionates pyruvate into acetyl-CoA and formic acid. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Acetyl-CoA」の詳細全文を読む スポンサード リンク
|