Table 1 Rate constants for the early steps of O2 reduction at low and high temperature for pH 7 and 10, respectively.

Errors are the SDs for n = 3 (pH 10 data) or n = 4 (pH 7 data) measurements.

Rate constant (s−1) (Time constant) (μs)
T (°C)pH 7pH 10
O2 binding (610-nm decay)10(2.8 ± 0.8) × 105 (3.6)(2.9 ± 0.1) × 105 (3.4)
45(2.7 ± 0.8) × 105 (3.7)(4 ± 1) × 105 (2.5)
Heme b oxidation (kb) (560-nm decay)10(9 ± 4) × 104 (11)(2.6 ± 0.6) × 104 (38)
45(1.9 ± 0.2) × 105 (5.3)(1.9 ± 0.2) × 105 (5.3)
PR formation (kP) (610-nm increase)10(9 ± 1) × 103 (110)(8.7 ± 0.3) × 103 (120)
45(1.8 ± 0.5) × 105 (5.5)(1.5 ± 0.5) × 105 (6.7)
Ratio (kb/kP)10103
451.11.3