Requirements for generating sigmoidal time-course aggregation in nucleation-dependent polymerization model.

Requirements for generating remarkable sigmoidal time-course of aggregation are found in the nucleation-dependent polymerization model by a numerical calculation method; i.e. there are optimum values of the kinetic constants to afford prominent sigmoidal character by inducing slightly unfavorable nucleation. However, if the nucleus formation is too unfavorable, sigmoidal character is again decreased. This result is in contrast to the generally accepted idea that sigmoid is induced by thermodynamically unfavorable nucleation phase.