Open AccessIntermediates in the Interconversion of Acid and Alkaline Ferrihemoglobin
Author(s) -
CHANCE Britton,
RUMEN Nevenka M.
Publication year - 1976
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1976.tb10034.x
Subject(s) - ammonia , chemistry , dissociation (chemistry) , reaction rate constant , acid dissociation constant , inorganic chemistry , kinetics , organic chemistry , aqueous solution , physics , quantum mechanics
The acid‐alkaline pH jump in suspension of crystalline sheep hemoglobin has been studied in the range 5.95 to 8.94. Crystals suspended in 3.8 M Cs 2 SO 4 show a rapid optical transition of half‐time equal to or less than 2 ms. As the ammonia concentration is increased in the Cs 2 SO 4 ‐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.