Table 3. Kinetic and thermodynamic constants for 6cNO AXCP complexes in pH 8.9 buffer solutions at 25 °C ^a .

Res16	Distal 6cNO	Proximal 5cNO	k 6on (M–1 s–1)	k 6off (s–1)	K D (M)	k 6-5 (M–1 s–1)	Reference
Ala	Product	no	2.9 × 106	2.0 × 10–7	6.90 × 10–14	no	12
Val	Product	no	1.52 (±0.03) × 106	7.80 × 10–5	5.13 × 10–11	no	tw
Ile	Product	no	1.79 (±0.15) × 106	1.78 × 10–5	9.94 × 10–12	no	tw
Leu (wt)	Intermediate	Product	4.33 (±0.04) × 104	6.0 × 10–3	1.40 × 10–7	1.14 (±0.04) × 104	9
Phe	Intermediate	Product	8.88 (±0.37) × 103	nd	nd	3.57 (±0.68) × 103	tw

^aAbbreviations: no; not observed, tw; this work, nd; not determined..