Table 2.

Binding to abrin fraction I and abrin agglutinin.

Binder	Abrin frac I			Abrus Agglutinin
	on, 1/Ms	off, 1/s	Kd, M a	on, 1/Ms	off, 1/s	Kd, M a
mAb 5F6	1.6 × 105	12.1 × 10−4	1.3 × 10−9	1.5 × 105	6.3 × 10−4	4.3 × 10−9
mAb 18E11	1.2 × 105	1.1 × 10−2	8.5 × 10−8	1.8 × 105	1.6 × 10−2	9.0 × 10−8
Abr1	NB	NB	NB	NB	NB	NB
Abr2	NB	NB	NB	1.1 × 106	1.6 × 10−5	1.4 × 10−11
Abr4	1.5 × 105	1.6 × 10−4	1.1 × 10−9	5.1 × 105	4.9 × 10−4	9.5 × 10−10
N5	NB	NB	NB	1.8 × 105	5.3 × 10−5	2.9 × 10−10
N12	NB	NB	NB	1.6 × 106	4.2 × 10−6	2.6 × 10−12
Abr6	4.0 × 104	2.1 × 10−4	5.2 × 10−9	9.1 × 104	2.6 × 10−5	2.9 × 10−10
3E	1.2 × 105	1.6 × 10−4	1.3 × 10−9	5.3 × 105	4.2 × 10−4	7.8 × 10−10
10C	3.2 × 105	6.5 × 10−4	2.0 × 10−9	1.2 × 106	8.1 × 10−4	6.6 × 10−10

NB = no binding observed; ^a Kd values are calculated from kd/ka; Binding constants for mAbs were determined using a bivalent model while those for sdAb were done with a Langmuir model.