Flash photolytic studies of carbon monoxide binding to the ferrous chains of [Mn(II),Fe(II)] hybrid hemoglobins: kinetic mechanism for the early stages of hemoglobin ligation. Academic Article uri icon

abstract

  • Flash photolysis is employed to investigate the kinetics of CO recombination to the ferrous chains of [Mn(II),Fe(II)] hemoglobin (Hb) hybrids. At low pH (6.6), Hb remains predominantly in the T quaternary state for the first two CO ligation steps, when binding to either the alpha chains or beta chains. At elevated pH, CO binding to the alpha chains produces a larger degree of T to R conversion than binding to the beta chains, in support of earlier equilibrium measurements. This study provides the full pH dependence of the CO binding rate constants for both alpha- and beta-Fe chains within the T state and at elevated values of pH gives the R-state rate constants for the monoliganded analogues. The data can be analyzed within the context of a two-state model for Hb cooperativity, but they give clear evidence for slow quaternary structure interconversion at the monoliganded level.

published proceedings

  • Biochemistry

author list (cited authors)

  • Blough, N. V., Zemel, H., & Hoffman, B. M.

citation count

  • 12

complete list of authors

  • Blough, NV||Zemel, H||Hoffman, BM

publication date

  • June 1984