What amino acids have nonpolar, aliphatic R groups? Glycine, Alanine, Proline,
Valine, Leucine, Isoleucine, Methionine What amino acids have polar,
uncharged R groups? Serine, Threonine, Cysteine, Asparagine, and Glutamine
What amino acids have aromatic R groups? Phenylalanine, Tyrosine, and
Tryptophan What amino acids have negatively charged R groups? Aspartate and
Glutamate What amino acids have positively charged R groups? Lysine,
Arginine, and Histidine
What is isoelectric focusing? Proteins are electrophoresed in a pH gradient gel.
Each protein will move in the gel as long as the protein contains a charge
What does SDS do? It binds to proteins and denatures it. All proteins have same
mass/ charge ratio
How do you determine the Amino Terminus? 1. Make a derivative of the N-
terminus with a marker molecule
2. Hydrolyze the peptide
3. N-terminal AA is identified by chromatography- modified amino acid will
elute differently than unmodified AA
What molecule does Edman Degradation use? Phenyl Isothiocyanate (PTH)
What does Edman Degradation do? It removes one amino acid at a time. The
limit is 50 amino acids. After 50 amino acids, the polypeptide must be
hydrolyzed into smaller fractions
Where does Cyanogen Bromide cleave? Cleaves only on the caryboxyl side
of Methionine residues
