Page - (000214) - in Biomedical Chemistry: Current Trends and Developments

intermediate (once again, likely dehydroalanine) (adapted from Turanov, 2011). Figure 3.1.4: Structures of non-protein α-AA (ornithine, citrulline, homo-cysteine) and non-α-AA (taurine, β-alanine). The catabolism of several AA exhibit a number of common characteristics throughout different organisms. Important metabolites of AA include ammonia, CO2, long-chain and short-chain fatty acids, glucose, H2S, ketone bodies, nitric oxide (NO), urea, uric acid, poly- amines, and other nitrogenous substances with enormous biological importance. Complete oxidation of AA carbons occurs only if their carbons are ultimately converted to acetyl-CoA, which is oxidized to CO2 and H2O via the Krebs cycle and the mitochondrial electron transport system (Wu, 2009). Biotransformation of amino acids into bioactive molecules can be essential in biomedical considerations, such as the hydroxylation of Tyr into L-Dopa (hihydroxyphenylalanine) followed by another decarboxylation to produce dopamine in the brain (Youdin, 2006). Histamine is a small molecule derived from the decarboxylation of the amino acid histidine (Haas, 2008). Trp is processed to form serotonin, a neurotransmissor that is linked to depression at low levels (Oxenkrug, 2013). After the action of serine dehydratase, Ser is converted into aminoacrylate that tautomerizes to the imine which then hydrolyzes into pyruvate and ammonia (Birolo, 1995). Arg is hydrolysed to urea and ornithine by arginase before it can be used for the synthesis of polyamines or Pro (Grillo & Colombatto, 2004). Arg is also associated with Glu formation, as well His. Met reacts with ATP to form S-