Biochem 4000 Lecture 1 PI

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  1. Nonpolar amino acids
    • Glycine
    • Alanine
    • Proline
    • Valine
    • Leucine
    • Isoleucine
    • Tryptophan
    • Phenylalanine
    • Methionine
  2. Polar uncharged amino acids
    • Serine
    • Threonine
    • Asparagine
    • Cysteine
    • Glutamine
    • Tyrosine
  3. Polar charged amino acids
    • Histidine
    • Lysine
    • Glutamate
    • Aspartate
    • Arginine
  4. Frequency of nonpolar residues?
    50%
  5. Frequency of polar uncharged residues
    24%
  6. Frequency of polar charged residue
    26%
  7. Top three most common amino acids
    • 1. Leucine
    • 2. Alanine
    • 3. Glycine
  8. Three least common amino acids
    • 1. Tryptophan
    • 2. Cysteine
    • 3. Histidine
  9. Aliphatic residues are more or less frequent?
    Much more frequent
  10. Sulfur containing residues are more or less frequent?
    Less frequent
  11. Aromatic residues are more or less frequent?
    Less frequent
  12. How are amino acids classified?
    According to the physiochemical properties of their R-group (especially polarity)
  13. Polarity
    Magnitude of the dipole induced in the presence of an external electromagnetic field
  14. How is molecular polarity approximated in amino acids?
    Using the fraction of polar bonds
  15. Two residues having multiple forms at neutral pH
    • Cysteine (-SH or -C-S-S-C-)
    • Histidine (pKa close to 7, polar or polar charged)
  16. Residues with intermediate polarity
    • Glycine - Small R-group, charged proton
    • Tyrosine - Polar OH on large aromatic ring
  17. Hydrophobicity
    Lacking affinity for water or inability to dissolve
  18. What types of residue tend to be hydrophobic?
    Nonpolar
  19. Hydrophobic effect
    Tendency of water to minimize contact with hydrophobic compounds
  20. Why is classification based on hydrophobicity common?
    It's easy to measure
  21. How is hydropathy (hydrophobicity) quantified?
    Solute partitioning experiments (sep funnel)
  22. Equation for free energy of hydropathy
    ΔG = -(RT)ln(Xnp/Xaq)
  23. Formula partition coefficient of hydropathy
    K = Xnp/Xaq
Author:
Ant
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314570
Card Set:
Biochem 4000 Lecture 1 PI
Updated:
2016-02-11 21:04:58
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Biochemistry 4000
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Biochem 4000
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