a. You have been approached by a biotech company to help write a protocol for the
purification of a protein X that has been expressed in Lactococcus lactis and secreted
into the culture supernatant. Briefly describe a one-step chromatographic procedure
that you will recommend for purifying protein X directly from the culture supernatant
and state three (3) factors that need to be controlled to ensure the stability of protein X
during the purification process.
b. What is the molecular basis for protein concentration determination at a wavelength of
280 nm and why is this method not accurate for determining the concentration of- uncharacterized
proteins or protein mixtures?
2.
a. Scurvy is a corrective tissue—related disease that is caused by a lack of ascorbic acid.
Based on your knowledge of protein structure and function, explain the molecular
basis of this disease.
b. A protein W is reduced by treatment with 2—mercaptoethanol and when subjected to
dansylation, yields a product that is chromatographically confirmed to contain glycine.
Treatment of the reduced protein W with trypsin yields the following four peptides fragments;
i) Gly-Ala-Phe-Asp-Met-Arg ii) Cys-Met-Tyr-Lys iii) Cys-Asp-Trp-Cys-Lys
iv) Gly-Glu-Ala
purification of a protein X that has been expressed in Lactococcus lactis and secreted
into the culture supernatant. Briefly describe a one-step chromatographic procedure
that you will recommend for purifying protein X directly from the culture supernatant
and state three (3) factors that need to be controlled to ensure the stability of protein X
during the purification process.
b. What is the molecular basis for protein concentration determination at a wavelength of
280 nm and why is this method not accurate for determining the concentration of- uncharacterized
proteins or protein mixtures?
2.
a. Scurvy is a corrective tissue—related disease that is caused by a lack of ascorbic acid.
Based on your knowledge of protein structure and function, explain the molecular
basis of this disease.
b. A protein W is reduced by treatment with 2—mercaptoethanol and when subjected to
dansylation, yields a product that is chromatographically confirmed to contain glycine.
Treatment of the reduced protein W with trypsin yields the following four peptides fragments;
i) Gly-Ala-Phe-Asp-Met-Arg ii) Cys-Met-Tyr-Lys iii) Cys-Asp-Trp-Cys-Lys
iv) Gly-Glu-Ala
