If antibody binds to normal tissues it can cause damage to the body or create other disease symptoms. Rheumatoid arthritis is a good example of an autoimmune disease. Antibodies that react with body tissues are felt to contribute to joint swelling and pain.
In eukaryotic cells the pyruvate decarboxylation occurs inside the mitochondria, after transport of the substrate, pyruvate, from the cytosol. The transport of pyruvate into the mitochondria is via a transport protein and is active, consuming energy. Passive diffusion of pyruvate into the mitochondria is impossible because it is a polar molecule. On entry to the mitochondria the pyruvate decarboxylation occurs, producing acetyl CoA.
The decarboxylation occurs with the help of NAD, which is converted to NADH. The enzyme that catalyzes this reaction is alpha-ketoglutarate dehydrogenase. The mechanism of this conversion is very similar to what occurs in the first few steps of pyruvate metabolism.The resulting molecule is called succinyl-CoA.he first reaction of the citric acid cycle is catalyzed by the enzyme citrate synthase. In this step, oxaloacetate is joined with acetyl-CoA to form citric acid. Once the two molecules are joined, a water molecule attacks the acetyl leading to the release of coenzyme A from the complex. Figure %: Reaction 1.