THE DISSOCIATION OF CARBON-MONOXIDE FROM THE ALPHA-SUBUNIT AND THE BETA-SUBUNIT OF HUMAN CARBONMONOXY HEMOGLOBIN
Articolo
Data di Pubblicazione:
1987
Citazione:
THE DISSOCIATION OF CARBON-MONOXIDE FROM THE ALPHA-SUBUNIT AND THE BETA-SUBUNIT OF HUMAN CARBONMONOXY HEMOGLOBIN / M. SAMAJA, E. ROVIDA. - In: BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS. - ISSN 0006-291X. - 148:3(1987), pp. 1196-1201. [10.1016/S0006-291X(87)80259-0]
Abstract:
We have measured the intrinsic CO dissociation rates from the subunits of the human hemoglobin tetramers (αCO βNO)2 and (αNO βCO)2 using microperoxidase and a stopped-flow spectrophotometer. The dissociation of NO is negligible. The rate constants for the and the subunits are similar (0.014 s-1 vs. 0.011 s-1, respectively, at pH 7, 20 C; and 0.016 s-1 for both in the presence of inositol hexaphosphate), indicating that they are equivalent in the first step of the CO dissociation. Therefore, the chain unequality observed in the third and fourth steps (Samaja, M., Rovida, E., Niggeler, M., Perrella, M., and Rossi-Bernardi, L. (1987). J. Biol. Chem.: 262, 4528-4533) are not due to the intrinsic properties of the subunits, but to the conformational state of the molecule.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
M. Samaja, E. Rovida
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