Table 1.

Kinetic^a and equilibrium constants for the binding of lipid-free apoE isoforms to LRP1

Protein	ka1 (M−1 s−1)	kd1 (1/s)	ka2 (1/s)	kd2 (1/s)	bKD (nM)	cKD (nM)
dApoE2	3.4 ± 0.4 × 104	8.6 ± 0.5 × 10−2	1.0 ± 0.2 × 10−2	2.8 ± 0.4 × 10−3	529 ± 75	493 ± 86
dApoE3	4.3 ± 0.8 × 104	9.0 ± 0.7 × 10−2	9.6 ± 0.1 × 10−3	2.6 ± 0.2 × 10−3	456 ± 48	398 ± 67
dApoE4	6.2 ± 0.7 × 104	6.5 ± 0.4 × 10−2	9.9 ± 0.3 × 10−3	2.7 ± 0.3 × 10−3	202 ± 51	236 ± 101

^aKinetic constants were obtained by fitting the data to a bivalent binding model.

^bThe equilibrium binding constant K_A was calculated using the following equation: K_A = (k_a1/k_d1) ∗ (1 + (k_a2/k_d2)), and K_D was calculated as: K_D = 1/K_A.

^cCalculated from equilibrium SPR measurements, in which Req was determined by fitting the association data to a pseudo first-order process to determine Req.

^dSix independent experiments were performed, and the values shown are the average ± SD.