STABILIZATION OF FISH MYOSIN SUBFRAGMENT-1 BY ADENOSINE 5'-TRIPHOSPHATE AND BY SORBITOL

The stabilizing effect of ATP and its analogues on fish myosin subfragment-1 (S-1) was investigated under various conditions. ATP strongly stabilized all S-1 tested, and ADP was less effective. The effect of PPi depends upon S-1s from fish species and KCl concentration for the thermal treatment; in 0.1 M KCl, carp and rabbit S-1 were both stabilized by PPi, while tilapia S-1 was destabilized upon PPi addition. ATP and its analogues increased the turbidity of S-1 solution just as change in ATPase inactivation rate. The protective effect of sorbitol was similarly observed even after S-1 was fully stabilized by ATP binding.