TAILIEUCHUNG - Lecture Organic chemistry - Chapter 26: Amino acids
In nature, the most common representatives are 2-amino acids (α-amino acids) with the general formula RCH(NH2)COOH. This chapter provides knowledge of amino acids. The main contents of this chapter include all of the following: structure and properties of amino acids, synthesis of amino acids: a combination of amine and carboxylic acidchemistry,.and other contents. | Chapter 26: Amino Acids In nature, the most common representatives are 2-amino acids (α-amino acids) with the general formula RCH(NH2)COOH. R = alkyl, acyl, amino, hydroxy, mercapto, sulfide, carboxy, guanidino, or imidazolyl groups Amino acids give rise to polyamides: polypeptides (proteins, enzymes) Amide linkage For proteins, n ≥ 8000 and MW > 1,000,000. Proteins are crucial for transport (O2, hemoglobin), energy storage, catalysis, control of reactions, template for RNA/DNA action, antibodies, etc. More than 500 natural amino acids known Among the 20 main amino acids, 8 cannot be synthesized by the body (essential amino acids) Names: We use common names. α-Stereocenter usually S (or, old nomenclature, L, from L-glyceraldehyde) Essential amino acids Used in reversible disulfide bridging Monosodium glutamate (MSG) R ! Amino acids are acidic and basic: Exist as zwitterions pKa = 9-10 pKa = 2-3 Zwitterion Glycine as a zwitterion H3NCH2COO– + Synthesis of Amino Acids .
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