Amyloid Aggregation Kinetics

Amyloid fibrils form via nucleation-elongation: primary nucleation creates seeds (rare, rate ∝ m^n_c), elongation adds monomers (rate k_+), and secondary nucleation on fibril surface accelerates growth (rate ∝ M·m^n_2). This generates characteristic sigmoidal curves with a lag phase that shortens with higher initial monomer concentration.

Kinetic Parameters

Initial monomer m₀: 5.0 μM Primary nuc. rate k_n: 0.01 Elongation rate k₊: 2.0 Secondary nuc. k₂: 0.05 Primary nuc. order n_c: 2

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Knowles et al. (2009, Science) showed secondary nucleation on fibril surface dominates kinetics in many amyloids (Aβ, α-synuclein). Lag time t_lag ∝ m₀^(-n_c/2) for primary-nucleation dominated regime.