Amino Acids
True or false. All naturally occurring amino acids are L isomers in S configurations.
True
Name the peptide IMFWP.
Isoleucine-methionine-phenylalanine-tryptophan-proline
What does gel filtration chromatography separate proteins on the basis of?
Size
Which enzyme cleaves on the C-side of R and K?
Trypsin
True or false. Myoglobin contributes to 35% of the dry weight in red blood cells.
False
This amino acid has a phenol functional group in its R group. What is the one letter abbreviation for this amino acid?
Y
True or false. Collagen is an example of a globular protein.
False, it’s a fibrous protein
Which type of ELISA uses an antigen-coated well?
Indirect ELISA
Which enzyme cleaves disulfide bridges?
2-mercaptoethanol
Which molecule facilitates the transfer of oxygen from the mother’s hemoglobin to the fetus?
2,3-BPG
How many nitrogen atoms are in the R group of histidine?
2
What kinds of residues on amino acids destabilize the alpha structure?
Steric hindrance (Val, Leu, Thr), competing H-bonds with the main chain (Ser, Asn, Asp), and conformation restriction (Pro)
In isoelectric focusing, would you expect proteins with a high pI to migrate towards the cathode or the anode?
Cathode
Name the one-letter codon of amino acid(s) cleaved by cyanogen bromide.
M
True or false. High pH increases the affinity of hemoglobin to oxygen.
True
Name the three-letter and one-letter abbreviations of amino acids with carboxylic groups.
Asp and Glu; D and E
I started with a functional protein. I added urea and BME. I first remove BME and then remove urea. Do I have an active protein?
No
True or false. In indirect ELISA, the rate of color formation is proportional to the amount of antigen.
False
True or false. Edman degradation cleaves the C-terminal.
False, carboxypeptidases
What mutation causes sickle cell anemia?
Valine for glutamic acid substitution
Name the three-letter and one-letter abbreviations of amino acids with two chiral centers.
Ile and Thr; I and T
What’s the PI of Asp-Gly-Glu?
3
Draw a diagram of 2D Gel Electrophoresis on the board and label each corner that separates proteins on the basis of pI and mass.
Top left: low pI, high mass;
Top right: high pI, high mass;
Bottom left: low pI, low mass;
Bottom right: high pI, low mass
Name the four accessory groups required in solid phase peptide synthesis.
FMOC, DCC, Resin, and protecting groups
High Kd increases or decreases a protein’s affinity to ligands.
Decreases