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Proteins Amino acids and peptides,

Proteins Amino acids and peptides,. Lec. Dr. Muthana A. Al-Shemeri. Video. myoglobin pdb code: 1WLA. Bacteriorhodopsin pdb code: 1AP9. Anti-parallel  -sheets of lectin pdb code: 2LAL. Parallel  -sheets carbonic anhydrase pdb code: 1QRM. Properties of Amino Acids.

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Proteins Amino acids and peptides,

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  1. Proteins Amino acids and peptides, Lec. Dr. Muthana A. Al-Shemeri

  2. Video

  3. myoglobin pdb code: 1WLA Bacteriorhodopsin pdb code: 1AP9 Anti-parallel -sheets of lectin pdb code: 2LAL Parallel -sheets carbonic anhydrase pdb code: 1QRM

  4. Properties of Amino Acids • Capacity to polymerize • Novel acid-base properties • Varied structure and chemical functionality • Chirality

  5. The name protein is giving to compounds containing more than 100 amino acids. An amino acid part in a polypeptide or protein is called residue. • D-amino acids are not found in proteins but found in nature. • Crystalline amino acids are colorless, odorless, and melt with decomposition at temperature more than 200 °C. • The physical properties of amino acids are resemble those of inorganic salt such as sodium chloride

  6. Functions of proteins • Enzymes : biological catalysis that are vital to all living systems. They are simple or conjugated proteins. • Structural proteins: proteins that hold living systems together such as collagen. • Hormones: proteins that act as messengers such as insulin. • Transport proteins: proteins that carry molecules and ions from one place to another in the living system such as hemoglobin carry oxygen from lung to cells. • Protective proteins: proteins that destroy any foreign substance released into the living system by an infections agent. • Toxin: proteins that are poisons such as snake venom.

  7. carboxyl group amino group a-carbon side chain Basic Amino Acid Structure • a-carbon is chiral (except for glycine) • at pH 7.0 uncharged amino acids zwitterion. • amino acids have a tetrahedral structure

  8. Proteins are make about two third of dry weight of cell • Major compounds of muscle, skin, and bones • The molecular weight varied from several thousand to several millions • Treated with a boiled acids or bases solution hydrolyzed the smaller compounds. • Twenty amino acids are obtain from hydrolysis of all living systems.

  9. Amino Acid Enantiomers • Steroisomers / enantiomers • Biological system only synthesize and use L-amino-acids

  10. Amino Acid Classification • Aliphatic • Aromatic • Sulfur containing • Polar/uncharged • basic/acidic Hydrophobic Hydrophillic

  11. Peptide bond formation

  12. Reaction of amino acids • The thiol side chain is oxidized by the oxygen in air or oxidizing agent to form two cysteine molecules.

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