Table 3.

Barnase-barstar dissociation constants at different ionic strengths^*

I, M	Off rate (s−1) in free solution†	On rate (107 M−1⋅s−1) in free solution†	KD, nM in free solution	KD, nM at the mitochondrial surface‡
0.05	1.2  ± 0.1	14  ± 1	9  ± 1	18  ± 1
0.07	1.1  ± 0.3	6.8  ± 0.6	16  ± 5	23  ± 2
0.17	1.0  ± 0.2	2.3  ± 0.2	43  ± 8	51  ± 3

^*All measurements were with barnase precursors with a Thr⁶ → Ala + Ile⁷⁶ → Val + Ile⁸⁸ → Val + Ile⁹⁶ → Val mutant background. All errors are SE. 

^†Determined at 35°C in import buffer lacking BSA. 

^‡Determined at 35°C in import buffer.