Reductive nitrosylation of ferric human serum heme-albumin.

Heme endows human serum albumin (HSA) with heme-protein-like reactivity and spectroscopic properties. Here, the kinetics and thermodynamics of reductive nitrosylation of ferric human serum heme-albumin [HSA-heme-Fe(III)] are reported. All data were obtained at 20 degrees C. At pH 5.5, HSA-heme-Fe(II...

Full description

Bibliographic Details
Published in:FEBS Journal
Main Authors: P. Ascenzi, Y. Cao, A. d. Masi, F. Gullotta, G. D. Sanctis, M. Coletta, FANALI, GABRIELLA, FASANO, MAURO
Other Authors: P., Ascenzi, Y., Cao, A. d., Masi, F., Gullotta, G. D., Sancti, Fanali, Gabriella, Fasano, Mauro, M., Coletta
Format: Article in Journal/Newspaper
Language:unknown
Published: 2010
Subjects:
Animal
Ferric Compound
Heme
Horse
Human
Kinetic
Nitric Oxide
Oxidation-Reduction
Rabbit
Serum Albumin
Sperm Whale
Thermodynamics
Sperm whale
Online Access:http://hdl.handle.net/11383/1718486
https://doi.org/10.1111/j.1742-4658.2010.07662.x
Description
Summary:Heme endows human serum albumin (HSA) with heme-protein-like reactivity and spectroscopic properties. Here, the kinetics and thermodynamics of reductive nitrosylation of ferric human serum heme-albumin [HSA-heme-Fe(III)] are reported. All data were obtained at 20 degrees C. At pH 5.5, HSA-heme-Fe(III) binds nitrogen monoxide (NO) reversibly, leading to the formation of nitrosylated HSA-heme-Fe(III) [HSA-heme-Fe(III)-NO]. By contrast, at pH >or= 6.5, the addition of NO to HSA-heme-Fe(III) leads to the transient formation of HSA-heme-Fe(III)-NO in equilibrium with HSA-heme-Fe(II)-NO(+). Then, HSA-heme-Fe(II)-NO(+) undergoes nucleophilic attack by OH(-) to yield ferrous human serum heme-albumin [HSA-heme-Fe(II)]. HSA-heme-Fe(II) further reacts with NO to give nitrosylated HSA-heme-Fe(II) [HSA-heme-Fe(II)-NO]. The rate-limiting step for reductive nitrosylation of HSA-heme-Fe(III) is represented by the OH(-)-mediated reduction of HSA-heme-Fe(II)-NO(+) to HSA-heme-Fe(II). The value of the second-order rate constant for OH(-)-mediated reduction of HSA-heme-Fe(II)-NO(+) to HSA-heme-Fe(II) is 4.4 x 10(3) M(-1) s(-1). The present results highlight the role of HSA-heme-Fe in scavenging reactive nitrogen species.

Similar Items