Table 1.

Excision activity in HeLa cell nuclear extract (μmol oligo/μg protein/min)

Substrate	Activity
U ss	2.3  × 10−8
U:A	6.3  × 10−8
U:G	8.0  × 10−8
HmU ss	3.2  × 10−11
HmU:A	4.7  × 10−11
HmU:G	2.7  × 10−9

Excision activities on oligonucleotide substrates containing U or HmU [single-stranded (ss), paired with A, or mispaired with G] were calculated from measurements of the initial rates.