Table 3.

Influence of the Mg²⁺ concentration on the inhibition of ssDNA synthesis by NRTIs

	(−) Strand strong stop DNA (%)a
	6 mM Mg2+	6 mM Mg2+ + 3.5 mM ATPb	2 mM Mg2+	2 mM Mg2+ + 3.5 mM ATPc
No NRTI	12	17	17	34
	10d			29d
ddATP	1.3	3.8	3.5	29
	0d			16d
ddCTP	1.1	1.1	2.6	24
3TCTP	5.4	10	8.9	27
d4TTP	1.8	2.8	3.2	21
AZTTP	0.05	0.11	0.31	13
	0d			8d

^a([(−) strong stop DNA]/[extended + unextended primer]) × 100.

^bThe calculated free Mg²⁺ concentration is 2.6 mM.

^cThe calculated free Mg²⁺ concentration is 0.1 mM.

^dThese experiments were performed with RNase H(−) RT.