Table 2.

Pre-steady-state kinetic parameters of the WT and mutant APE1 proteins

APE1 Variant	[APE1]active (nM)	kobs (s−1)	kss (s−1)
3′ mismatch (exo)
WT	26 ± 2	0.9 ± 0.2	0.045 ± 0.008
F266A	25 ± 5	21 ± 7	2.1 ± 0.7
M270A	22 ± 4	1.9 ± 0.9	0.13 ± 0.03
R177A	13 ± 1	1.0 ± 0.2	0.14 ± 0.01
W280A	17 ± 4	0.5 ± 0.2	0.21 ± 0.05
THF (endo)
WTa	11	36 ± 6	0.8 ± 0.1

^a Freudenthal, B. D. et al.¹¹