View
- Term
- Definition
- Both Sides
Study
- All (12)
Shortcut Show
Next
Prev
Flip
BIOSC 1000: CHAPTER 3: AMINO ACIDS, PEPTIDES, AND PROTEINS
enantiomers
|
nonsuperposable mirror images...true of all AA
|
polarity |
tendency to interact with water at biological pH
|
Nonpolar, aliphatic R groups
|
Glycine (little hydrophobic interactions), Alanine, Proline (aliphatic side chain), Valine, Leucine, Isoleucine, and Methionine (nonpolar thioether group)
|
Aromatic R groups
|
Phenylalanine (least polar of the 3), Tyrosine (can H bond), and Tryptophan. Relatively nonpolar, all can participate in hydrophobic interactions
|
Polar, Uncharged R groups
|
contain functional groups that form H bonds with water: Serine, Threonine, Cysteine, Asparagine, and Glutamine (both found in proteins and easily hydrolyzed)
|
Positively charged (basic) R groups
|
o Hydrophilic at pH 7
o Lysine- has second primary amino group on thealiphatic chain
o Arginine- pos charged guanidinium group
o Histidine-aromatic imidazole group
ยง pKa near neutrality and therefore can be chargedor uncharged at pH 7
|
Negatively Charged (Acidic) R groups
|
o Aspartate and Glutamate
Each of which have second COO group
|
pKa
|
tendency of a group to give up a proton
decreases 10x as the pKa increases by 1 unit
|
isoelectric point, pI
|
pH at which the net electric charge is zero
|
peptide
|
chains of amino acids
|
residue |
part left over after losing a H atom from its amino group and the hydroxyl moiety from its carboxyl group
|
N-terminal
|
amino-terminal with free alpha-amino group
|