And then we repeat that with the blue polypeptide. And at the end, we know exactly what the sequence of amino acid is in this protein that consists of these two polypeptide chains. Now, the final piece of information that we need to know is where exactly are these disulfide bonds? So we want to answer the following question how do we determine the position of the sulfide bonds in that protein that contains these disulfide bridges. So we have to follow three different steps. And what we use is a special process known as diagonal electrophoresis which is basically two different applications of the gel electrophoresis process as we'll see in just a moment.