How do I find the net charge of a protein at a given pH?

Question

anonymous · Answer

pH = -log [H+]

anonymous · Answer

Amino acids that make up proteins may be positive, negative, neutral, or polar in nature, and together give a protein its overall charge. At a pH below their isoelectric point proteins carry a net positive charge; above their pI they carry a net negative charge. Proteins can, thus, be separated according to their isoelectric point (overall charge) on a polyacrylamide gel using a technique called isoelectric focusing, which uses a pH gradient to separate proteins.

preetha · Answer

naf has it.  You can't just look at it and predict it.  Its made up of hundreds of amino acids and the resultant charge of hundreds of charges.

anonymous · Answer

thnx preetha

anonymous · Answer

Well what I meant to ask was, given a string of amino acids I need to determine the overall charge of the polypeptide. Based on your information and pKa value table I can determine the net charge though, correct?