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You know the molecular weight of the monomeric Encprotein; however you would like to get an idea of what the pI ofthe protein is. From the following options, what is the best way toestimate that?
[ ] SDS-PAGE
[ ] Size-exclusion chromatography
[ ] 2-D gel electrophoresis
[ ] "Salt out"
Protein analysis: You are attempting to separate a60-subunit protein, Enc, from a mixture of other proteins. Eachmonomer has a molecular weight of 29 kDa. At pH 7.0, the proteinhas a net charge of -12. Which of the following options is the bestway to purify this protein?
[ ] âSalt outâ via ammonium sulfate precipitation and ionexchange chromatography
[ ] Ion exchange chromatography and size-exclusionchromatography
[ ] SDS-PAGE and affinity chromatography
[ ] âSalt outâ via ammonium sulfate precipitation and affinitychromatography
I have two purified samples of the enzyme PKA (ProteinKinase A). One sample is treated with cAMP (cyclic AMP), while theother other is not. The cAMP-treated sample shows 2 bands on anon-denaturing PAGE, whereas the untreated sample shows only 1band. What is the best explanation for this result?
[ ] PKA is activated by cAMP. The active enzyme would show morebands.
[ ] PAGE causes denaturation of the PKA.
[ ] cAMP unfolds PKA.
[ ] cAMP dissociates the regulatory and catalytic subunits ofPKA.
You have some protein sample and you want to quantify itusing a spectrophotometer. You take a small sample of protein andput it in a quartz cuvette, take a wavelength scan, and observeabsorbance intensity at 280 nm. Which of the following is likely tomake it so that you can analyze protein using aspectrophotometer?
[ ] Very concentrated protein sample
[ ] Proteins are composed of chiral molecules
[ ] The number of Trp and Tyr residues found in the amino acidsequence
[ ] All of the above