Question

Electrophoresis of histones (pI = 8.5) and myoglobin (pI = 5.5) under non-denaturing conditions (pH = 7.0) results in the following:

A) histones migrate to the cathode (-); myoglobin migrates to the anode (+).
B) histones migrate to the anode (+); myoglobin migrates to the cathode (-).
C) both proteins migrate to the anode (+). D) both proteins migrate to the cathode (-).

Answer 1

Under non-denaturing conditions at pH 7.0, histones with a pI of 8.5 migrate to the cathode due to their positive charge, while myoglobin with a pI of 5.5 migrates to the anode because of its negative charge. The correct answer is: B).

Step-by-step explanation:

When performing electrophoresis under non-denaturing conditions at a pH of 7.0, the movement of proteins such as histones and myoglobin is dictated by their isoelectric point (pI). The isoelectric point is the pH at which a protein carries no net electrical charge. For histones with a pI of 8.5, at pH 7.0, they are positively charged because the pH is below their pI. Therefore, histones will migrate towards the cathode (-). Conversely, myoglobin with a pI of 5.5 will be negatively charged at pH 7.0, since the pH is above its pI, causing it to migrate towards the anode (+).

Thus, the correct answer is: B) histones migrate to the anode (+); myoglobin migrates to the cathode (-).