TABLE 1.

Oxygen binding properties and Bohr effect of Hb S and recombinant mutants

Experiments were conducted in 0.1 m sodium phosphate buffer at 29 °C in the presence of a methemoglobin reductase system (29). Values for the Bohr effect were estimated from the pH range in parentheses. Experiment results have an S.D. of <±4% between runs.

Hemoglobins	pH	P50	n50	−Δ(log P50)/ΔpH
Hb Aa	5.73	22.22	2.71	0.46 (pH 6.56–8.23)
	6.25	22.86	2.78
	6.56	22.44	2.82
	6.75	17.97	2.82
	7.06	14.80	2.78
	7.40	9.38	2.82
	7.83	5.61	2.69
	8.23	3.93	2.62
Hb S	5.75	21.73	2.90	0.48 (pH 6.52–7.99)
	6.22	22.84	2.95
	6.52	21.16	2.99
	7.01	14.08	3.09
	7.39	8.51	3.20
	7.99	4.34	3.12
rHb (βE6V/αH20Q)	5.82	20.98	2.61	0.45 (pH 6.51–8.23)
	6.26	21.91	2.73
	6.51	19.38	2.68
	7.02	13.13	2.78
	7.40	7.79	2.90
	7.71	5.49	2.93
	8.23	3.34	2.90
rHb (βE6V/αH20R)	5.80	21.61	2.81	0.48 (pH 6.51–8.10)
	6.27	22.50	2.88
	6.51	21.14	2.98
	6.97	13.63	2.85
	7.39	8.48	3.06
	8.10	3.75	2.99
rHb (βE6V/αH50Q)	6.53	23.74	2.97	0.43 (pH 6.77–8.02)
	6.77	20.06	2.87
	7.4	11.37	3.19
	7.66	7.96	3.15
	8.02	8.02	2.85
rHb (βE6V/αH20R/H50Q)	5.74	16.41	2.47	0.45 (pH 6.49–7.98)
	6.19	18.40	2.58
	6.49	16.41	2.58
	7.02	10.99	2.76
	7.38	6.93	2.93
	7.98	3.63	2.83
	8.62	2.81	2.78
rHb (βE6V/αH20Q/H50Q)	5.76	16.85	2.62	0.46 (pH 6.52–8.00)
	6.22	18.61	2.68
	6.52	17.08	2.68
	7.03	11.48	2.78
	7.41	7.07	2.81
	8.00	3.70	2.69
	8.70	2.60	2.57

^a Data from Tam et al. (31).