THE ROLE OF OXALATE IN THE RELAXING-FACTOR SYSTEM IN SKELETAL MUSCLE.

Abstract

1. Large amounts of the fresh microsomes prolonged the duration of the clear bphase, and inhibited the syneresis and ATPase of myosin B even in the absence of oxalate. These effects were increased by the addition of oxalate to the reaction mixture.In the absence of oxalate, the relaxing activity of the microsomes on the clear phase, syneresis and ATPase of myosin B fell off on the storage at 0°C.2. With the aged microsomes, in the presence of oxalate, the same effects as the fresh microsomes on the clear phase, syneresis and ATPase of myosin B were observed.3. In the absence of oxalate, the calcium binding activity of the microsomes decreased to about one-fifth to one-tenth of that in the presence of oxalate, and typical “extra” splitting of ATP was not observed even with the fresh microsomes. On the other hand, over 50 times larger amounts of the microsomes than that required in the presence of oxalate was required for 50% inhibition of the myofibrillar ATPase activity.4. The release of calcium from the aged microsomes was not observed.5. The protein-free effective eluate was separated in the absence of oxalate and its relaxing activity was not affected by the addition of oxalate.