Nitrite reductase activity of sol-gel-encapsulated deoxyhemoglobin: Influence of quaternary and tertiary structure

Camille J. Roche, David Dantsker, Uri Samuni, Joel M. Friedman

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31 Scopus citations


Nitrite reductase activity of deoxyhemoglobin (HbA) in the red blood cell has been proposed as a non-nitric-oxide synthase source of deliverable nitric oxide (NO) within the vasculature. An essential element in this scheme is the dependence of this reaction on the quaternary/tertiary structure of HbA. In the present work sol-gel encapsulation is used to trap and stabilize deoxy-HbA in either the T or R quaternary state, thus allowing for the clear-cut monitoring of nitrite reductase activity as a function of quaternary state with and without effectors. The results indicate that reaction is not only R-T-dependent but also heterotropic effector-dependent within a given quaternary state. The use of the maximum entropy method to analyze carbon monoxide (CO) recombination kinetics from fully and partially liganded sol-gel-encapsulated T-state species provides a framework for understanding effector modulation of T-state reactivity by influencing the distribution of high and low reactivity T-state conformations.

Original languageEnglish (US)
Pages (from-to)36874-36882
Number of pages9
JournalJournal of Biological Chemistry
Issue number48
Publication statusPublished - Dec 1 2006


ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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