Isoelectric point of protein?

Question

could someone help with this question plsss

you are given a protein with an isoelectric point of 6 dissolved in a buffer of pH8.... is the overall charge on this protein positive or negative, what type of ion exchange chromatography would u carry out to separate it from protiens of opposite charge by binding it to the column

Answer 1

The protein will be negatively charged because th high pH of the solution cause the solution to have a high hydroxide concentration (relatively) and will cause extraction of hydrogen atoms from acidic residues on the aminio acids of the protein. I would use a weak anion exchanger for the ion exchange chromatography of this protein.

Answer 2

or if you know this is the ONLY protein in your mixture with a -ve charge and all the others have a +ve charge, then use a cation exchanger which will bind all +ve ions (to a greater or lesser degree) and the -ve one will elute straight through for collection!

Answer 3

every protein have an isoelectric point since all are produced by addition of amino acids

Answer 4

eat a fillet steak....preferbly with garlic and lemon. green beens an some nice potatoes with lot of butter, feel sorry for you