Biosynthesis of Dispensable Amino Acids

A short-chain fatty add thiokinase catalyzes the ATP-dependent conversion of propionic acid to propionyl-CoA. Which cells of the gastrointestinal tract might be expected to have high levels of short-chain thiokinase and of methylmalonyl-CoA mutase. Hint see the section on Dietary Fiber in Chapter 3. 

The amino acids can be classified according to whether they are glucogenic or ketogenic. This classification is based on the pathways of catabolism followed by 

Isoleucine, phenylalanine, t5nrosine, tryptophan Alanine, serine, glycine, cysteine, aspartic add, asparagine, glutamic acid, glutamine, arginine, histidine, valine, threonine, methionine, praline 

Leucine and lysine are purely ketogenic amino adds. The catabolism of these amino acids does not yield intermediates of the Krebs cycle. It does not yield pyruvate. It does not produce compoimds that can result in the net synthesis of glucose. Leucine catabolism results in the production of a molecule of acetyl-CoA and a molecule of acetoacetate lysine breakdown produces acetoacetyl-CoA. 

Entry of Glucogenic Amino Acids into the Krebs Cycle 

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Biosynthesis of Dispensable Amino Acids Clucogt icand Ketogcnic Amino Adds... 

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