Answer A1 is wrong The procedure for purifying a certain enzyme calls for centri
ID: 88910 • Letter: A
Question
Answer A1 is wrong
The procedure for purifying a certain enzyme calls for centrifugation of the homogenate, then adding ammonium sulfate to the supernatant, and then a second centrifugation with the supernatant being retained and subsequently dialyzed. Which of the following statements is most likely TRUE? A. The enzyme of interest precipitated when ammonium sulfate was added. A. A benefit of dialysis is to remove impurities like chromosomal DNA. A. Cellular organelles like mitochondria would be removed in the first centrifugation pellet. A. Enzyme assays cannot be performed until after the dialysis is completed. A. All of the above are false.Explanation / Answer
Answer
A4. Enzyme assay cannot be performed until after the dialysis is completed.
The presence of one of the substrates in the enzyme solution can given a blank rate with an incomplete reaction mixture. Alternatively, if the contaminating subtrate is a small molecule, it should be removed by dialysis or gel filtration because the problem with the contaminated subtrate is that it would decrease the purification of the enzyme. Thus, it is necessary to to remove tsuch molecules by dialysis or gel filtration before assay.
Therefore, the correct answer is option (A4).