Table 1. Generation of G(-H)^• Radicals in DNA: Reaction Scheme and Rate Constants^a.

N	reaction	kn, M–1 s–1b
1		φ308 = 0.55c
2		(1.6 ± 0.2) × 109
3		(10.9 ± 0.9) × 109d
4		(8.6 ± 0.9) × 109d
5		(10.4 ± 0.9) × 109d

^aThe kinetic parameters were measured in air-equilibrated 10 mM phosphate buffer solutions, pH 7.0 containing 50 mM Na₂SO₄ at 24 ± 1 °C.

^bThe rate constants were obtained from the best least-squares fits of the appropriate kinetic equations to the transient absorption profiles describing the decay of SO₄^•– radicals at 445 nm (ε₄₄₅ = 1.6 × 10³ M^–1cm^–1)²⁷ and the formation of G(-H)^• radicals at 312 nm (ε₃₁₂ = 7.2 × 10³ M^–1cm^–1).^18,28

^cQuantum yield of SO₄^•– radicals at 308 nm.²⁹

^dThe G(-H)^• radicals form with the yields of 0.55 ± 0.10 calculated from the ratio of the transient absorbances of G(-H)^• and SO₄^•– radicals at 312 and 445 nm, respectively.