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Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO 2). Usually, decarboxylation refers to a reaction of carboxylic acids , removing a carbon atom from a carbon chain.
Pyruvate dehydrogenase complex (PDC) is a complex of three enzymes that converts pyruvate into acetyl-CoA by a process called pyruvate decarboxylation. [1] Acetyl-CoA may then be used in the citric acid cycle to carry out cellular respiration , and this complex links the glycolysis metabolic pathway to the citric acid cycle .
Probing this PLP-catalyzed decarboxylation, it has been discovered that there is a difference in concentration and pH dependence between substrates. DOPA is optimally decarboxylated at pH 6.7 and a PLP concentration of 0.125 mM, while the conditions for optimal 5-HTP decarboxylation were found to be pH 8.3 and 0.3 mM PLP.
It is used to inhibit the decarboxylation of L-DOPA to dopamine outside the brain, i.e. in the blood. This is primarily co-administered with L -DOPA to combat Parkinson's disease . Administration can prevent common side-effects, such as nausea and vomiting, as a result of interaction with D 2 receptors in the vomiting center (or cheomoreceptor ...
Glutamate decarboxylase or glutamic acid decarboxylase (GAD) is an enzyme that catalyzes the decarboxylation of glutamate to gamma-aminobutyric acid (GABA) and carbon dioxide (CO 2). GAD uses pyridoxal-phosphate (PLP) as a cofactor. The reaction proceeds as follows: HOOC−CH 2 −CH 2 −CH(NH 2)−COOH → CO 2 + HOOC−CH 2 −CH 2 −CH 2 NH 2
In several reactions, including that of pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, and transketolase, TPP catalyses the reversible decarboxylation reaction (aka cleavage of a substrate compound at a carbon-carbon bond connecting a carbonyl group to an adjacent reactive group—usually a carboxylic acid or an alcohol).
In contrast to the relatively facile decarboxylation of β-keto acids, the decarboxylation of α-keto acids presents a mechanistic challenge. Thiamine pyrophosphate (TPP) provides the biochemical and enzymological answer. TPP is the key catalytic cofactor used by enzymes catalyzing non-oxidative and oxidative decarboxylation of α-keto acids.
Two common decarboxylation products of protein associated with decomposition are putrescine and cadaverine. These compounds are toxic at high levels and have distinctive, foul odours. [ 6 ] It is believed that they are components of the characteristic odours of decomposition commonly detected by cadaver dogs .