Table 2. DNA synthesis fidelity of human Polκ.

DNA polymerasea	Mutation frequencyb	Point mutation (%)	Deletion (%)	Insertion (%)	Average mutations per targetc	Average mutation rate
Polκ	3.0 × 10–1	87.3	9.3	3.4	3.8	5.0 × 10–3
Polη	4.9 × 10–1	91.8	7.2	1.0	3.9	8.3 × 10–3
Polβ	2.7 × 10–2	36.6	58.5	4.9	1.3	1.5 × 10–4

^aHuman DNA polymerases κ, η and β were purified to apparent homogeneity and 400, 205 and 1200 fmol, respectively, were used in the M13mp2 DNA synthesis fidelity assays.

^bIn the M13mp2 fidelity assay, ∼60% phage plaques were derived from the gap filling strand (minus strand) (32). Thus, mutation frequency = (mutant plaques/total plaques) × 1/0.6. For the Polκ experiment, 2144 phage plaques were scored, of which 82 light blue and 301 colorless mutant phage plaques were observed. For the Polη experiment, 1577 phage plaques were scored, of which 142 light blue and 323 colorless mutant phage plaques were observed. For the Polβ experiment, 2349 phage plaques were scored, of which 3 light blue and 35 colorless mutant phage plaques were observed.

^cMutant phage clones sequenced in Polκ, η and β experiments were 53, 53 and 32, respectively. The target sequence is 229 nt of the E.coli lacZα gene (from nucleotide –84 to +145).