Table 1.

Characteristics of reactions of Co(I) and Co(II) with S₂O₄²⁻ (SO₂⁻) and SO₂²⁻

Constants	Complex
	Cobalamin	Cobinamide
k1S2O42−a/M−1 s−1	4.90 ± 0.45	6.13 ± 0.31
k1SO2−a/M−1 s−1	(1.35 ± 0.06)104	(2.82 ± 0.29)103
k−1S2O42−b/M−1 s−1	2.83 ± 0.11	2.18 ± 0.07
k−1SO2−b/M−1 s−1	5.92 ± 0.08	3.30 ± 0.11
KCo(I)/Co(II) (S2O42−)c/M−1	0.35 ± 0.05	0.57 ± 0.05
KCo(I)/Co(II) (SO2−)c/M−1	458.2 ± 26.6	172.4 ± 23.4

^adetermined at 25°C, pH 10 (0.1 M borate buffer).

^bobserved values determined at 25°C, pH 13 (0.1 M NaOH).

^cdetermined as a quotient of k¹ and k⁻¹.