Table 1.

Effects of biologically relevant cations and anions on kinetics of β-haematin formation mediated by MPG (0.54 L/H), citric buffer (50 mM, pH 4.8), 37°C^a

Added ion or biomolecule	Concentration (mM)		k(min−1) ± SEM (n = 4)
−		(control)	0.085 ± 0.006
Na+	8	RBC concentration	0.067 ± 0.006
Na+	150	serum concentration	0.031 ± 0.004
K+	150	RBC concentration	0.045 ± 0.005
Mg2+	1.75	RBC concentration	0.038 ± 0.005f
Mg2+	1.5	serum concentration	0.050 ± 0.005
Ca2+	3	serum concentration	0.030 ± 0.005f
H2PO4−	1	RBC concentrationb	0.033 ± 0.004
HCO3−	15	RBC concentrationc	0.026 ± 0.004
ATP	1.5	RBC concentration	0.039 ± 0.005
all ions combined	d	RBC concentrations	0.037 ± 0.006
all ions combined	e	serum concentrations	0.037 ± 0.003
glutathione	2.48	RBC concentration	0.024 ± 0.003g

^aAll ions were added to 50 mM citrate/sodium citrate buffer, which represents a background value. ^bTotal RBC phosphates. ^cAt pH 4.8 present as CO₂. ^d 8 mM Na⁺, 150 mM K⁺, 1 mM H₂PO₄⁻, 15 mM HCO₃⁻ and 1.5 mM ATP. ^e 150 mM Na⁺, 1.75 mM Mg²⁺ and 3 mM Ca²⁺. ^f 50 mM acetate/acetic acid buffer instead of citrate. ^g Under Ar, all solutions purged with Ar.