Thermal stability and aggregation of creatine kinase from rabbit skeletal muscle.: Effect of 2-hydroxypropyl-β-cyclodextrin

Effect of 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) on thermal aggregation of creatine kinase from rabbit skeletal muscle (RMCK) at 48 °C has been studied using dynamic light scattering. An increase in the duration of the lag period on the kinetic curves of aggregation, registered as an increment of the light scattering intensity in time, has been observed in the presence of HP-β-CD. It has been shown that the initial parts of the dependences of the hydrodynamic radius (Rh) of the protein aggregates on time follow the exponential law. The reciprocal value of parameter t2R (t2R is the time interval over which the Rh value is doubled) was used to characterize the rate of aggregation. A 10-fold decrease in the 1/t2R value was observed in the presence of 76 mM HP-β-CD. Judging from the data on the kinetics of RMCK inactivation and the data on differential scanning calorimetry of RMCK, HP-β-CD does not affect the rate of RMCK unfolding.