Table 1. SPR: BBK32/C1 and C1r binding parameters.

Immobilized Ligand	Analyte	K D (nM)	k a (M-1s-1)	k d (s-1)
BBK32-FL	C1	3.9 ± 0.31	(7.2 ± 0.24) x 104	(2.8 ± 0.14) x 10−4
	C1r enzyme	15 ± 7.5	(1.9 ± 1.1) x 104	(2.2 ± 0.85) x 10−4
BBK32-C	C1	2.3 ± 0.11	(8.4 ± 0.21) x 104	(1.9 ± 0.01) x 10−4
	C1r enzyme	32 ± 11	(3.9 ± 2.2) x 103	(1.1 ± 0.46) x 10−4

The dissociation constant (K _D), association rate constant (k _a) and dissociation rate constant (k _d) were calculated by performing kinetic analysis for each interaction. All experiments were performed between three and five times and errors are reported as the mean ± SEM.