Thiamine pyrophosphate (TPP)
There are very many enzymes involved. A few from glycolysis are: hexokinase and glucokinase, phosphohexose isomerase, phosphofructokinase, pyruvate kinase; from pyruvate decarboxylation are pyruvate dehydrogenase phosphatase and pyruvate dehydrogenase kinase; and a few from the Kreb's cycle are: aconitase, alpha-ketoglutamate dehydrogenase, succinate thiokinase, and fumarase.
Pyruvate decarboxylation is an irreversible reaction in cellular metabolism where pyruvate is converted into acetyl-CoA and carbon dioxide, primarily in the mitochondria. This process is catalyzed by the pyruvate dehydrogenase complex and is a key step linking glycolysis to the citric acid cycle. Due to its irreversibility, pyruvate decarboxylation cannot be reversed under normal physiological conditions, as the release of CO2 makes it energetically unfavorable to revert the reaction.
The enzyme that converts pyruvate into acetyl-CoA is pyruvate dehydrogenase. This multienzyme complex is responsible for catalyzing the conversion of pyruvate into acetyl-CoA, which is a key step in the metabolism of carbohydrates to produce energy.
Pyruvate dehydrogenase complex react with pyruvate to form acetyl-CoA
Yes, during the oxidation of pyruvate to acetyl CoA in the mitochondria, CO2 is released through decarboxylation reactions. This process is part of the pyruvate dehydrogenase complex, where pyruvate is converted to acetyl CoA, releasing CO2 as a byproduct.
Pyruvate decarboxylation -> Acetaldehyde reduction The product is ethanol. Pyruvate decarboxylation is performed by pyruvate decarxylase with cofactor thiamine pyrophosphate, and the product, acetaldehyde, is reduced by NADH. (Pyruvate decarboxylase is NOT the same as the pyruvate dehydrogenase complex in cellular respiration. Though pyruvate dehydrogenase also decarboxylates pyruvate, but the decarboxlated species immediately reacts with CoA to form acetyl-CoA).
In prokaryotes, the pyruvate dehydrogenase complex is located in the cytoplasm.
Correct answer: I, II, III and IV
Pyruvate dehydrogenase complex . . . mitochondrial matrix
Immediately after pyruvate enters the mitochondrion, it is converted into acetyl-CoA through a process called pyruvate decarboxylation. This reaction is catalyzed by the pyruvate dehydrogenase complex, which also produces carbon dioxide as a byproduct and reduces NAD+ to NADH. Acetyl-CoA then enters the citric acid cycle (Krebs cycle) to continue cellular respiration and energy production.
Alpha-ketoglutarate dehydrogenase is the most similar to Pyruvate dehydrogenase because both are part of the α-ketoglutarate dehydrogenase complex, involved in the citric acid cycle and share structural and functional similarities.
decarboxylation means removal of co2 from the reaction