300936 Lecture Notes - Lecture 9: Lactose Permease, Copolymer, Enolase
27 Feb 2019
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Document Summary
Functional proteins and genes: polypeptide chains are flexible yet conformationally restricted, protein structure stabilised by multiple weak interactions. But covalent bonds in polypeptide backbone place constraints on structure: proteins- main agents in biological function. Catalysis: enolase (in glycolytic pathway, dna polymerase (in replication) Transport: haemoglobin (transport 02 in blood, lactose permease (transport lactose across cell membrane) Structure: collagen (connective tissue, keratin (hair, nails, feathers, horns) Motion: myosin (muscle tissue, actin (muscle tissue, cell motility, primary structure of proteins- linear sequence (heteropolymer) of a-amino acids. Amino acids have properties well suited to carry out biological functions- capacity to polymerize, varied physical properties (charge, solubility), varied chemical properties (amphoteric, chirality, hydrophobicity, hydrophilicity). Protein structure: from primary to tertiary: levels of structure in proteins: primary- amino acid residues, secondary- a helix, tertiary- polypeptide chain, quaternary- assembled subunits. Primary structure: linear polymers formed by linked carboxyl group of one amino acid to amino group of another, polypeptide bond= amide bond.
