title: Albumin as a carrier for NO delivery: preparation, physicochemical characterization, and interaction with gold nanoparticles.
abstract: BACKGROUND
  Nitric oxide (NO) is a gaseous transmitter playing numerous physiological roles and characterized by a short half-life. Its binding to endogenous thiols increases its stability, facilitating its storage and transport. The purpose of this study was to investigate the nitrosated serum albumin (SA-SNO) and to provide a reference for its easy preparation for further use in in vitro studies.
  
  
  METHODS
  Serum albumin (SA) was S-nitrosated by reacting with (i) NaNO2in acidic medium; (ii) different low-molecular weight S-nitrosothiols (RSNO) (S-nitrosocysteine (CysNO), S-nitrosoglutathione (GSNO), and S,S'-dinitrosobucillamine (Buc(NO)2)); and (iii) diethylamine NONOate (DEA/NO). SA-SNO was purified by size exclusion chromatography and the S-nitrosation site and the rate were studied by mass spectrometry and Griess-Saville assay, respectively. Then, SA-SNO was characterized by spectrofluorimetry, dynamic light scattering, and circular dichroism. Finally, SA-SNO reactivity with citrate stabilized gold nanoparticles (AuNP-citrate) was investigated via determination of NO release.
  
  
  RESULTS
  S-nitrosation rates of SA were 90.1 ± 3.3, 76.8 ± 2.7, 80.3 ± 3.2, 84.8 ± 5.0, and 15.4 ± 1.9% (n = 5), when SA was reacted with acidified NaNO2, CysNO, GSNO, Buc(NO)2, and DEA/NO, respectively. The physicochemical characterization indicated that the resulting product corresponded to a mono-S-nitrosothiol (on cysteine-34), and the conformational construction remained unchanged. Stability studies showed that the NO content was preserved over 1 week. AuNP-citrate reacted with SA-SNO with increase of its hydrodynamic diameter but preservation of SNO bond.
  
  
  CONCLUSIONS
  SA-SNO prepared and stored under the reported conditions affords a well-defined reference suitable for in vitro studies.
authors.affiliation: a Université De Lorraine - CITHEFOR EA 3452 , Nancy Cedex , France ;
authors.forename: Ming
authors.initials: M
authors.lastname: Luo
authors.affiliation: a Université De Lorraine - CITHEFOR EA 3452 , Nancy Cedex , France ;
authors.forename: Ariane
authors.initials: A
authors.lastname: Boudier
authors.affiliation: a Université De Lorraine - CITHEFOR EA 3452 , Nancy Cedex , France ;
authors.forename: Arnaud
authors.initials: A
authors.lastname: Pallotta
authors.affiliation: a Université De Lorraine - CITHEFOR EA 3452 , Nancy Cedex , France ;
authors.forename: Philippe
authors.initials: P
authors.lastname: Maincent
authors.affiliation: b Université De Lorraine - IMoPA, UMR 7365 CNRS , Vandœuvre-lès-Nancy Cedex , France ;|c Proteomics Platform of Fédération De Recherche 3209 , Biopole De La Faculté De Médecine De Nancy , Vandœuvre-lès-Nancy Cedex , France.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Vincourt
authors.affiliation: a Université De Lorraine - CITHEFOR EA 3452 , Nancy Cedex , France ;
authors.forename: Pierre
authors.initials: P
authors.lastname: Leroy
keywords: Citrate-stabilized gold nanoparticles; S-nitrosation processes; conformational study; serum albumin; stability