PPT-Proteins Ch 11- Amino Acids and Peptides

Unit objectives Identify amino acid classifications based on nutritional use and chemical properties of side chains Describe the primary secondary tertiary and quaternary structures of proteins. CHAPTER 3, Part 1 . Amino Acids and Peptides . To know the structure and naming of all 20 protein amino acids. To know the structure and properties of peptides and the particularly the structure of the peptide bond.. Subunits (building blocks) of peptides and proteins. Neurotransmitters. Metabolic intermediates. glutamate. γ. -. aminobutyric. acid. (GABA). Proteins are synthesized from 20 ‘standard’ . α. -amino acids. Their names have 3- and 1-letter abbreviations.. B.2. Properties of 2-amino acids . (B.2.2). Zwitterion. (dipolar) . amino acids contain both acidic and basic groups in the same molecule . therefore, are . amphoteric. in nature (capable of behaving as acids or bases). Polypeptides . are chains of amino acids linked together by condensation reactions. the main, or only, component in proteins. Some proteins are composed of only one polypeptide chain, while others are made of 2 or more. 6. 6.1 Differentiate . between essential amino acids and nonessential amino acids.. 6.2 List . the functions of protein in the body.. 6.3 List . the steps for protein digestion and absorption in the body. . A. PHYSICAL PROPERTIES. Optical properties: . All amino acids except glycine possess optical isomers due to the presence of asymmentric carbon atom. Some amino acids have a second assymmentric carbon e.g. isoleucine, threonine.. Each amino acid (aa) shares a common structure; i.e. an amine (NH. 2. ) group, an acid group (COOH), and a central carbon atom bonded to hydrogen and to a side chain (R).. The side chains qualify aas as acidic, basic, neutral, aromatic, and sulphur-containing amino acids.. Peptide bond formation. : . α-carboxyl group of one amino acid (with side chain R1) forms a covalent peptide bond with α-amino group of another amino acid . ( . with the side chain R2) by removal of a molecule of water. The result is : Dipeptide ( i.e. Two amino acids linked by one peptide bond). By the same way, the dipeptide can then forms a second peptide bond with a third amino acid (with side chain R3) to give . Amino Acids are the building units of proteins.. The main role of amino acids is in the synthesis of structural and functional . proteins.. The . non-essential amino acids are either derived from the. Presented . by. Ms. . P. . . H. . Giri. Department of Microbiology. Deogiri . College, Aurangabad. B.Sc. F. Y.. Semester II. Paper No. V. Basic Biochemistry. Unit 3 Proteins. Ms. . Priyanka. H. . Giri. A. . Peptides. are compounds, formed of less . than . 50 . amino acids . linked together by peptide bonds.. 1.. . Dipeptide. (2 amino acids and one peptide bond).. 2.. . Tripeptide. (3 amino acids and two peptide bonds).. amino acid. This structure is common to . all . but one of the . α. - amino . acids.. exception . structure, size, and electric charge, and which influence. the . solubility of the amino acids in water. BSc 3. rd. year . AMINO ACIDS. C. lassification of amino acids . Classification according to nature of side chain. PREPARATION OF AMINO ACIDS. 1. Gabriel Phthalimide synthesis. 2. Strecker’s synthesis. Proteins. Part I. Dr. Ravish Chauhan. Associate Professor. IGN College, Ladwa. . . Amino Acids. . These are the compounds which contain both amino and carboxylic group.