Table 1. Haem stock solutions prepared.

Haem powder is dissolved in 0.1 M NaOH, pH 12, by gentle pipetting and inversion for 5 min, and incubation at room temp for 10 min before use.

Haem stock 1	10 mM
Haem diluted stock 2	1 mM
Haem diluted stock 3	500 μM
Haem diluted stock 4	100 μM