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Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is the first chemical step in photosynthesis , is called carboxylation , the addition of CO 2 to a compound.
In animal tissue, BCKDC catalyzes an irreversible step [2] in the catabolism of the branched-chain amino acids L-isoleucine, L-valine, and L-leucine, acting on their deaminated derivatives (L-alpha-keto-beta-methylvalerate, alpha-ketoisovalerate, and alpha-ketoisocaproate, respectively) and converting them [3] to α-Methylbutyryl-CoA, Isobutyryl-CoA and Isovaleryl-CoA respectively.
Pyruvate decarboxylation is also known as the "pyruvate dehydrogenase reaction" because it also involves the oxidation of pyruvate. [ 2 ] This multi-enzyme complex is related structurally and functionally to the oxoglutarate dehydrogenase and branched-chain oxo-acid dehydrogenase multi-enzyme complexes.
These enzymes catalyze the decarboxylation of amino acids and alpha-keto acids. [1] Classification and nomenclature
The enzyme is necessary to help the decarboxylation of alpha-keto acids because there is a build-up of negative charge that occurs on the carbonyl carbon atom in the transition state; therefore, the enzyme provides the suitable environment for TPP and the alpha-keto acid (pyruvate) to meet. [4]
Energy-generating ions and molecules, such as amino acids and carbohydrates, enter the Krebs cycle as acetyl coenzyme A and oxidize in the cycle. [5] The pyruvate dehydrogenase complex (PDC) catalyzes the decarboxylation of pyruvate, resulting in the synthesis of acetyl-CoA, CO 2, and NADH.
Cu(I)-only systems have also been found to promote coupling of alkynyl carboxylic acids with aryl halides (see aryl alkynes below), as well as decarboxylative dehydrogenative cross-coupling of amino acids with alkynes (or similar nucleophiles). [5] [6] Cu-catalyzed decarboxylative coupling of amino acids, reported by Jiang et al.
The first step in the mechanism is the formation of a Schiff base with the substrate amino group. [5] The lysine residue binding PLP to the structure is replaced by diaminopimelate . [ 4 ] [ 7 ] DAPDC then uses the interaction of 3 residues ( Arginine , Aspartate , and Glutamate ) within the active site to identify the D-stereocenter.