Protein Fiber Nucleation & Growth

Amyloid fibrillation: nucleation-dependent polymerization. Monomers form nuclei (slow) then elongate (fast). Shows the characteristic sigmoidal aggregation curve with lag phase.

Kinetics

Nucleation rate kₙ: 0.001 Elongation rate k₊: 0.05 Monomer conc. C₀: 1.0 nc (nucleus size): 3

Nucleated polymerization kinetics (Oosawa-Kasai model). Nucleation: n monomers → nucleus with rate kₙ[M]^nc. Elongation: fiber + monomer → fiber+1 with rate k₊[M]. The lag time t_lag ∝ 1/√(kₙ k₊) [M]^(nc/2+1/2).