. 2007 Sep 18;35(18):6297–6310. doi: 10.1093/nar/gkm536

Table 2.

ATPase, helicase, DNA binding and ATP binding activities of the wild-type and mutant BLM proteins

Helicases	ATPase				Helicase				DNA binding		ATP binding

	V_m	K_M	k_cat	k_cat/K_M	A₁	k_obs,1	A₂	k_obs,2	ssDNA	dsDNA	[ATP]/[Protein]
	µM·min⁻¹	µM	s⁻¹	s⁻¹·mM⁻¹	%	s⁻¹	%	s⁻¹	nM	nM
BLM^642–1290	164.2 ± 9.3	80.7 ± 2.0	13.7	169.5	62.8 ± 0.6	0.52 ± 0.01	23.2 ± 0.6	0.05 ± 0.01	7.2 ± 0.4	9.8 ± 1.1	1.02 ± 0.23
Q672R	127.6 ± 11.4	1755 ± 127	10.6	6.0	16.2 ± 0.1	0.03 ± 0.01			10.9 ± 0.8	15.3 ± 1.9	0.22 ± 0.04
I841T	39.8 ± 7.4	ND^a	3.3	ND					12.1 ± 1.2	14.8 ± 1.5	1.01 ± 0.15
C878R	196.5 ± 11.5	3460 ± 693	16.3	4.7	30.2 ± 0.1^b	0.01 ± 0.01			168 ± 10	327 ± 27	0.97 ± 0.23
G891E	4.6 ± 0.9	ND	0.38	ND					352 ± 12	349 ± 12	0.98 ± 0.14
C901Y	5.8 ± 0.8	ND	0.48	ND					475 ± 25	122 ± 18	0.89 ± 0.27

^aND: cannot be determined precisely. The ATP saturation curves of the BLM^642–1290 and its corresponding variant were fitted by Michaelis–Menten, Lineweaver–Burk and Eadie–Hofstee equations. The ATP saturation curves of BLM^642–1290, Q672R and C878R were fitted well by the three equations, yielding similar V_m and K_m values, whatever the fitting procedure. In contrast, for poorly active mutants, I841, G891E and C901Y, the Lineweaver–Burk and Eadie–Hofstee plots were not linear. For these mutants, only the V_m values were precisely recovered by fitting with the Michaelis–Menten equation.

^bData obtained with 150 nM protein.