Because the four interchain disulfide bonds are clustered in the highly-flexible hinge region and much more solvent-accessible than other (intra-chain) disulfide bonds, reduction with an excess of, for example, a reducing agent, such as but not limited to dithiothreitol (DTT), Tris(2-carboxyethyl)phosphine (TCEP), or 2-Mercaptoethanol, breaks all four bonds and generates eight cysteines (i.e., con