Well, logically speaking, if we don't know anything about that protein that we just isolated, what we want to do first is we want to actually determine what the amino acid composition is within that protein. So we want to know what types of amino acids are found within that protein and how many of each amino acid is found within that protein. So how do we calculate this information? How do we find this information? So this is what we're going to look at in this lecture. So we're going to begin by assuming we know what our protein is.