proteinnotes - -Uses polystyrene beads via a CH 2 Cl...

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Polypeptide (protein) notes H 2 N N H H N O O O N H H N O O OH H 3 N CH 2 CH 2 S CH 3 CH 2 OH CH 3 HO CH 3 H CH 2 CH 2 C OH O H N H O H N O H CH 3 O H N H HC O H N H O O H CH 2 CH 2 S CH 3 CH 2 OH OH CH 3 CH 2 CH 2 C O O MetTyrAlaThrGlu Fischer projection @ pH7 Line drawings: Dashes down Wedges up N -> C Peptides can be hydrolized with acid and water into their individual amino acids (residues) Protein structure is created by: i) hydrophobic effect ii) hydrogen bonding iii) covalent cross links a) disulfide bond b) imine bond c) aldol condensation CH 2 S-H H-SCH 2 oxidation CH 2 S SCH 2 a) disulfide bond between two cysteines b) imine (CH 2 ) 3 H 2 N(CH 2 ) 4 O H allysine lysine (CH 2 ) 3 (CH 2 ) 4 N H (CH 2 ) 3 O H allysine (CH 2 ) 3 O H allysine (CH 2 ) 3 (CH 2 ) 2 O H c) aldol condensation Acid Protecing Groups easy on easy off OCH 2 Ph = OBn benzyl OCH 3 = OMe methyl O CH 3 CH 3 CH 3 = OtBu t-butyl Coupling reagent: DCC dicylohexyl urea N C N HO CH 3 CH 3 CH 3 HCl HOCH 2 Ph, HCl HOCH 3 , HCl H 2 Pd/C HBr (anh) CF 3 COH O OR HBr (anh) Base Protecting Groups Solid state synthesis necessary to improve yield to 99%+ in order to achieve a reasonable overall yield
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Unformatted text preview: -Uses polystyrene beads via a CH 2 Cl group-Synthesis runs C to N terminus-Bead acts like a benzyl protecting group and can be removed in the same manner easy on easy off O C OCH 2 Ph = Cbz O C O = Boc CH 3 CH 3 CH 3 S n 2 S n 1 S n 2 S n 1 H 2 Pd/C OR HBr (anh) CF 3 COH O O C OCH 2 Ph O C O CH 3 CH 3 CH 3 Cl + base N 3 Problems: 1) Propose a synthesis for LysProMet 2) Draw the peptide GlyAspCysArg at its pI. Sketch the titration curve for this tetrapeptide. Label each half equivalance point and each equivalence point with the appropriate pH. 3) Draw a each the Fischer projection and a dash and wedge drawing of LeuTrpAsp at pH ~7 4) Starting with the bead below, propose a solid state synthesis for the oligopeptide IleProVal Cl Peptide synthesis in the lab...
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