Structural Changes in Cod Myosin after Modification with Formaldehyde or Frozen Storage

摘要

Structural changes in cod myosin after formaldehyde (FA) addition with and without subsequent freezing at - 18℃ were examined by Raman spec- troscopy, ANS hydrophobicity, solubility and SDS-PAGE profiles. Protein solubility decreased by >90/100, whereas ANS fluorescence showed little change, possibly due to a balance between soluble and insoluble fractions differing in exposed hydrophobicity. SDS-PAGE showed irreversible in- solubilization at increasing FA concentration, especially after frozen stor- age. Raman spectral analysis indicated a change in secondary structure of aquacide concentrated myosin preparations, from 95/100 a-helix in the con- trol (no FA) to 60/100 after 12 mM FA treatment. Changes in vibrational modes assigned to aliphatic residues suggested involvement of hydropho- bic interactions after FA addition or frozen storage.