There are several key steps to sequencing a protein, including: 1) Separating individual protein chains and breaking disulfide bonds. This can involve reagents like mercaptoethanol or performic acid. 2) Purifying individual protein chains using techniques like electrophoresis or chromatography. 3) Cleaving the purified protein into fragments using enzymes like trypsin or chemicals like cyanogen bromide. 4) Determining the amino acid sequence of each fragment, then combining the overlapping sequences to deduce the full protein sequence.