. Author manuscript; available in PMC: 2010 Aug 6.

Published in final edited form as: DNA Repair (Amst). 2009 Jul 8;8(8):961–968. doi: 10.1016/j.dnarep.2009.06.002

Table II.

Kinetics of DNA ligation by hLigI, IIIα, IIIβ, and IV on nicked and DSB substrates. Enzyme activity parameters were obtained from reactions containing 1 pmol of each ligase in a 20 μl reaction.

ligase	substrate	K_m (μM)	k_cat (min⁻¹)	relative k_cat	k_cat/K_m (M⁻¹·s⁻¹)
I	nick	1.6 ± 0.2	6.6 ± 0.2	100	69,000
I	dsb	0 ± 0.0	0 ± 0.0	0	n/a
IIIα	nick	1.3 ± 0.2	5.5 ± 0.3	83	71,000
IIIα	dsb	1.2 ± 0.2	1.4 ± 0.1	21	20,000
IIIβ	nick	1.4 ± 0.3	4.9 ± 0.4	74	58,000
IIIβ	dsb	2.9 ± 0.5	1.2 ± 0.1	18	7,000
IV	nick	n/a	0.2 ± 0.1	3	n/a
IV	dsb	n/a	0.3 ± 0.1	5	n/a