So they have have quotinary structure. And the question is, if a protein has quotinary structure, if a protein consists of two or more polypeptide chains, how do we sequence these types of proteins? So how do we determine the amino acid sequence in proteins that consists of two or more polypeptide subunits? So there are three steps that we essentially have to follow. In step one, what we want to do is we want to take our quarterly structure and break it down. We want to denature our protein.