Intermediates in the interconversion of acid and alkaline ferrihemoglobin. Structural and kinetic aspects.
The acid-alkaline pH-jump in suspension of crystalline sheep hemoglobin has been studied in the range of 5.95 to 8.94. Crystals suspended in 3.8 M Cs2SO4 show a rapid optical transition of half-time equal to or less than 2 ms. As the ammonia concentration is increased in the Cs2SO4-suspended crystals, a second optical transition is observed as a pseudo-first-order reaction, with a rate constant of between 10 and 15 s-1. The alkaline-acid pH-jump proceeds through a very rapid shift of the alkaline-acid equilibrium and is followed by a first-order dissociation constant between 9 and 12 s-1. The dissociation of the ammonia is biphasic, and the ratio between the fast and slow phases is 9.
Intermediates in the interconversion of acid and alkaline ferrihemoglobin. Structural and kinetic aspects. The acid-alkaline pH-jump in suspension of crystalline sheep hemoglobin has been studied in the range of 5.95 to 8.94. Crystals suspended in 3.8 M Cs2SO4 show a rapid optical transition of half-time equal to or less than 2 ms. As the ammonia concentration is increased in the Cs2SO4-suspended crystals, a second optical transition is observed as a pseudo-first-order reaction, with a rate constant of between 10 and 15 s-1. The alkaline-acid pH-jump proceeds through a very rapid shift of the alkaline-acid equilibrium and is followed by a first-order dissociation constant between 9 and 12 s-1. The dissociation of the ammonia is biphasic, and the ratio between the fast and slow phases is 9.