Question

In paper electrophoresis, you separated amino acids based on charge. What is the variable this time in SDS-PAGE? How do you know that there is only one variable in this separation? Explain in detail.

Answer 1

The most important variable must be the [H+] which is related to the pH

the pH is essentially the H+ ions in solution.

Note that the amin acids will charge positively and/or negatively according to the pH

Some of the amino acids will get protons from solution to form NH2 + H+ --> NH3+

and vice versa.

Some carboxlic acids from amino acids will free/get H+ ions in soution COOH --> COO- + H+

That is the only variable, since the amino acids will only charge with respect to pH