Insolubilizing and adhesive studies of water-soluble synthetic model proteins

Insolubilizing and adhesive studies of water-soluble synthetic copoly(Tyr1 Lysx) (x = 1-10) were examined using tyrosinase in water and simulated seawater systems. Tyrosinase oxidized tyrosine aromatic nuclei, causing intermolecular crosslinking reactions, which have been assigned by the absorption band at around 360 nm. The viscosities of the model polypeptides were affected by salinity and the kinds of salts in solution systems. As a whole the amino acid compositions, salinity, system pH and beta-structure conformation are considered to play roles in the insolubilizing reaction. The bonding strengths of the model polypeptides exhibited tensile strengths of 16-24 kg/cm2 without enzyme and 29-31 kg/cm2 with tyrosinase on iron, and increased up to 10 kg/cm2 on metals by the addition of tyrosinase as an oxidant.