Table 2. Intrinsic oxygen affinities and anaerobic redox potentials of bottlenose dolphin Hb and adult human Hb in anion-free 0.05 M HEPES buffer at pH 7.5, 20°C, and consequences of adding inorganic or organic anionic effectors.

Redox potentials are given vs NHE and were determined in the presence of a cationic mediator, 0.5 mM Ru(NH₃)₆. Entries are for Hb from Buster, which has a single type of Hb, and for the “Mixed” Bottlenose Dolphin Hbs of Peak II, which contained one type of α chains and three types of β chains. The dolphin Hbs in the presence of IHP oxidized rather quickly. They exhibited somewhat lower oxygen affinities in the presence of IHP (the higher P₅₀ values listed) when measured in the presence of a cocktail of reagents developed for enzymatic heme reduction (Imai, 1982).

Protein and effectors	Oxygenation Log P50	Oxidation E1/2
Buster Bottlenose Dolphin Hb	0.20	76
with 0.2 M Cl−	0.53	105
with 2.5−10 fold excess IHP	1. 3−1.6	119
Mixed Bottlenose Dolphin Hbs	0.20	57
with 0.2 M Cl−	0.58	96
with 2.5−10 fold excess IHP	1. 3−1.6	108
Adult Human Hb (HbA0)	−0.02	72
with 0.2 M Cl−	0.25	103
with 2.5−10 fold excess IHP	1.66	127