posted by Andrew .
On preparation of a solution of protein, you attempted to dissolve the substance in water, but a suspension resulted. Drop-wise adition of NaOH solution, with stirring, eliminated the suspension. Addition of acid to the original suspension had no effect. Think about how pH affects the charge on a protein and explain the phenomenon.
I don't know where to start! Someone please help?
Read the part about pH and pI carefully. The answer is there. Remember that adding NaOH will form the Na salt and adding HCl can form the amine salt.
So with NaOH... it's a strong base... it denatured the protein so it eliminated the suspension? Adding acid to the original suspension didn't do anything because it didn't denature the protein?
In strong acid, the protein is exposed to the strong acid and the charge is neutral as the protein gains a proton. In strong base, the protein is exposed to OH- and postive (as a proton is being taken away).