Friday, December 31, 2010

Understanding amino acid metabolism

Chemical processes by which amino acids are either synthesized or are broken down and are used for energy in the body.
Amino acid synthesis is important because approximately half of the different amino acids used as PROTEIN building blocks can be made from CARBOHYDRATES.
Amino acids such as ALANINE, GLUTAMIC ACID, and GLUTAMINE made by the brain and MUSCLE help transport NITROGEN waste products via the bloodstream to the LIVER for disposal. When amino acids are degraded, the first step (transamination) releases nitrogen with the help of VITAMIN B6. The final nitrogen-containing waste product is UREA. The second step of amino acid degradation requires the oxidation of the carbon atoms of amino acids to produce ATP, the energy currency of cells. The waste product is CARBON DIOXIDE. An alternative route permits the liver to convert most amino acids to blood sugar (GLUCOSE) when the diet does not provide adequate carbohydrates that can be digested to glucose to fuel the brain. This process is called GLUCONEOGENESIS. HEME (the pigment of red blood cells), neurotransmitters (brain chemicals that carry nerve impulses), purines (building blocks of RNA and DNA), and HORMONES represent important amino acid derivatives.

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