A mixture of Alanine (pl 6.02), Glutamic Acid (pl 3.22), Glycine (pl 5.79), Lysine (pl 9.74) and Threonine (pl 6.53) are separated by cation exchange chromatography. What is the order of elution of these amino acids if you use gradient buffer system from pH 10 to pH 2 ? - v First 1. Alanine - v Second 2. Glutamic Acid v Third 3. Glycine - v Fourth 4. Lysine v Fifth 5. Threonine 6. No separation

1.0.1 mL of a protein solution of concentration of 11 mg/mL was diluted to a total volume of 4.0 mL with water (i.e. 0.1 mL of the solution was added to 3.9 mL of water). 2 mL of this solution was then mixed with 18 mL of water. What is the concentration of the diluted protein solution? Space to show your workings:

A tetrameric protein dissociates into dimers when the detergent sodium dodecyl sulfate (SDS) is added to a solution of the protein. But the dimers are termed SDS-resistant because they do not further dissociate into monomers in the presence of the detergent. What intermolecular forces might be acting at the dimer-dimer interface? Are the intermolecular forces acting at the monomer-monomer interface different? Explain.

A stock solution contains 0.2 mg/mL protein. From this stock solution, 179 uL is diluted with 1.1 mL buffer. What is the concentration of protein in this dilution?

Would each of the following ions of serine exist at a pH above, below, or at its pI? Drag the appropriate items to their respective bins. Above pl H₂N-CH-COO CH₂OH H₂N-CH-COOH CH₂OH Below pl H₂N-CH-COO CH₂OH At its pl Reset Help

Titration curve of an unknown amino acid The graph below shows a curve, which was obtained following titration of an unknown amino acid. Include a suitable descriptive title stating the identity of the unknown amino acid Use rectangles to precisely outline the regions in the graph where ionisable groups show buffering activity (base/acid ratio 1:10 to base/acid ratio 10:1); clearly associate the name of the ionisable group with the buffering regions; indicate within the graph all observable titration mid-points and all observable titration end-points and indicate estimates of the pKa of the three functional groups (do not provide pka values from the literature, you need to read the pka from the titration curve provided). Note that it is not possible to estimate the pka with more than one decimal precision due to limited resolution of the shown graph.

A purified protein fraction has a total sample volume of 360 µL.  The sample has a corrected A280 of 0.484, and the blank corrected A280 was 0.052.  (Both values were measured with a path length of 1.00 cm.)  If 5.00 µL of the sample was used in a reaction, calculate the mass of protein in the reaction (in µg).