after removal of tropomyosin and troponin from the ; natural ' actomyosin complex , the adenosine triphosphatase activity of the resulting ; desensitized ' actomyosin is stimulated to the same extent by various bivalent cations with an ionic radius in the range 0.65-0.99a when tested at optimum concentration of the metal ion in the presence of 2.5mm-atp at low ionic strength and ph7.6 .
C0007447
cations
C0022023
ion