Physicochemical characterization of cross-linked human serum albumin dimer and its synthetic heme hybrid as an oxygen carrier

Teruyuki Komatsu, Yukiko Oguro, Yuji Teramura, Shinji Takeoka, Junpei Okai, Makoto Anraku, Masaki Otagiri, Eishun Tsuchida

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

The recombinant human serum albumin (rHSA) dimer, which was cross-linked by a thiol group of Cys-34 with 1,6-bis(maleimido)hexane, has been physicochemically characterized. Reduction of the inert mixed-disulfide of Cys-34 beforehand improved the efficiency of the cross-linking reaction. The purified dimer showed a double mass and absorption coefficient, but unaltered molar ellipticity, isoelectric point (pI: 4.8) and denaturing temperature (65°C). The concentration dependence of the colloid osmotic pressure (COP) demonstrated that the 8.5 g dL -1 dimer solution has the same COP with the physiological 5 g dL -1 rHSA. The antigenic epitopes of the albumin units are preserved after bridging the Cys-34, and the circulation lifetime of the 125I-labeled variant in rat was 18 h. A total of 16 molecules of the tetrakis{(1-methylcyclohexanamido)phenyl}porphinatoiron(II) derivative (FecycP) is incorporated into the hydrophobic cavities of the HSA dimer, giving an albumin-heme hybrid in dimeric form. It can reversibly bind and release O 2 under physiological conditions (37°C, pH 7.3) like hemoglobin or myoglobin. Magnetic circular dichroism (CD) revealed the formation of an O 2-adduct complex and laser flash photolysis experiments showed the three-component kinetics of the O 2-recombination reaction. The O 2-binding affinity and the O 2-association and -dissociation rate constants of this synthetic hemoprotein have also been evaluated.

Original languageEnglish
Pages (from-to)21-31
Number of pages11
JournalBiochimica et Biophysica Acta - General Subjects
Volume1675
Issue number1-3
DOIs
Publication statusPublished - 2004 Nov 18

Keywords

  • Albumin-heme dimer
  • Colloid osmotic pressure
  • Cross-linking
  • Human serum albumin dimer
  • Oxygen carrier
  • Synthetic heme

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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