Abstract
Hydropathic mass (HM) has been used to display the characterization of hydrophilicity and hydrophobicity of proinsulin. The a-helix of the B chain (residues 9-19), which is located at the inner part of the crystalline insulin, possesses a strong positive HM. The proteolytic sites of proinsulin for insulin maturation are located in the most negative HM regions. This suggests that they are exposed to the exterior of the molecule, which contributes to the digestion by proteases during insulin maturing.