Table 2. Cleavage activity of S.cerevisiae PI-SceI, the DH1-1A homing endonuclease and singly substituted PI-SceI endonucleases^a.

Protein	Activity (×10–2)b	Relative activityc
S.cerevisiae	2.6 ± 0.3	1
DH1-1A	0.25 ± 0.05	0.1
R44S	3.0± 0.3	1.2
V67M	2.4± 0.3	0.9
I132V	2.0± 0.1	0.8
I276V	1.7± 0.2	0.7
V291I	2.3± 0.1	0.9
V361A	3.6± 0.1	1.4
A409V	1.9± 0.1	0.7
A411T	3.1± 0.1	1.2
A413V	2.0± 0.1	0.8
R417Q	0.47± 0.1	0.2
D429N	2.7± 0.1	1.1

^aValues represent means ± SD from at least three experiments.

^bUnits are M DNA cleaved/(min × M enzyme).

^cRelative activity is the ratio of the DH1-1A or singly substituted PI-SceI to S.cerevisiae values.