TABLE 3.

Kinetic parameters of Fab 3/11 and AP33 binding to peptide and sE2

Affinity	kon (M−1 · s−1) ± SE	koff (s−1) ± SE	Kd (nM) (±SE)
“Glasgow” peptide over:
Fab AP33a,b	5.9 × 105 ± 0.5 × 105	3.1 × 10−2 ± 0.2 × 10−2	55.3 (±3.6)
Fab 3/11a,b	4.6 × 105 ± 0.4 × 105	3.6 × 10−3 ± 0.3 × 10−3	7.9 (±0.7)
“H77” peptide over:
Fab AP33a,b	5.1 × 105 ± 0.3 × 105	2.5 × 10−2 ± 0.1 × 10−2	50.9 (±3.3)
Fab 3/11a,b	3.9 × 105 ± 0.2 × 105	2.6 × 10−3 ± 0.2 × 10−3	6.5 (±0.4)
Fab 3/11 over:
sE2b	4.1 × 103	2.7 × 10−4	65
sE2 ΔHVR1b	15 × 103	4.1 × 10−4	26
Denatured sE2 ΔHVR1b	11 × 103	5.0 × 10−4	44
Fab AP33 over:
sE2b	35 × 103	13 × 10−4	38
sE2 ΔHVR1b	45 × 103	43 × 10−4	97
Denatured sE2 ΔHVR1b	29 × 103	57 × 10−4	196

^aFab affinities for the peptide were determined in three independent experiments and are shown as mean values with standard errors.

^bk_off values were determined by globally fitting dissociation profiles alone, while k_on and K_d values were determined by globally fitting association and dissociation profiles simultaneously.