抄録
The stability of actomyosin from carp during ice storage was studied focusing onthe effect of disulfide bond formation on the protein conformational change. Behavior of characteristics of the protein in the presence of cryoprotectants and a reducing reagent during ice storagewas investigated by measuring SH content, Ca2+-ATPase activity and surface hydrophobicity, and by performing SDSPAGE.
In the case of no additives, a decrease in SH content and a dimer formation of myosin heavy chain (MHC) through SS bonding were observed along with a decrease in Ca2+-ATPase activity and an increase in surface hydrophobicity. The dimer formation of MHC proceeded even in the presence of cryoprotectants, although the Ca2+-ATPase activity was stabilized throughout ice storage. In addition, a slight change in surface hydrophobicity was also observed. On the other hand, the addition of a reducing reagent (dithiothreitol) showed that the decrease in Ca2+-ATPase activity and the increase in surface hydrophobicity occurred without the dimer formation of MHC through SS bonding.
Therefore, it was suggested that the oxidation of SH groups in myosin heavy chain and the MHC dimer formation by SS bonding proceed regardless of the conformational change of myosin head portion related to Ca2+-ATPase activity during ice storage.
