Hexa-thiocarbamoyl phenyl PEG5K Hb: Vasoactivity and structure : Ithe conjugation linkage on the pegylation induced plasma expander-like solution properties of PEG-Hb adducts

Fantao Meng, Belur N. Manjula, Amy G. Tsai, Pedro Cabrales, Marcos Intaglietta, Paul K. Smith, Muthuchidambaram Prabhakaran, Seetharama A. Acharya

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

A new hexaPEGylated hemoglobin, (TCP-PEG5K)6-Hb (TCP, thiocarbamoyl phenyl) has been developed using PEG-phenyl-isothiocyanate and its vasoactivity and structure has been investigated. Of the six PEG5K chains of (TCP-PEG5K)6-Hb, 4 are conjugated to the α-amino groups of Hb, and the other 2 chains are distributed on ε-amino groups, identified as Lys-40(α) (∼45%), Lys-56(α) (∼25%), and Lys-8(β) (∼24%). The studies with hamster infused with a bolus of a 4 gm % solution of (TCP-PEG5K)6-Hb equivalent to 10% of their blood volume have established that this new hexaPEGylated Hb is vasoinactive. The viscosity and the colloidal osmotic pressure of (TCP-PEG5K)6-Hb at 4% is 1.9 cP and 69.7 mmHg, respectively. The molecular radius of (TCP-PEG5K)6-Hb is about 4.6 nm and is significantly smaller than hexaPEGylated Hbs developed using other direct and extension arm facilitated PEGylation platform. The presence of an outside the central cavity intramolecular crosslink, succinimidophenyl-PEG2K between Cys-93(β, β′) in (TCP-PEG5K)6-ββ- Hb strongly impacts its solution properties. These patterns of influence suggest that the inter-dimeric interactions in (TCP-PEG5K)6-Hb is weakened just as with other direct PEGylation platforms, and (SP-PEG5K)6-Hb generated by EAF-PEGylation is unique in not inducing this effect. A comparison of the properties of hexaPEGylated Hbs establishes that rigidity of the conjugation linkage between PEG and Hb plays a significant influence on the resultant dictating solution properties and/structure/conformation of PEG-Hb adduct.

Original languageEnglish (US)
Pages (from-to)199-212
Number of pages14
JournalProtein Journal
Volume28
Issue number5
DOIs
StatePublished - Jun 1 2009

Keywords

  • Blood substitute
  • Conjugation chemistry
  • Hemoglobin
  • Linkage rigidity
  • PEGylation
  • Vasoactivity

ASJC Scopus subject areas

  • Analytical Chemistry
  • Bioengineering
  • Biochemistry
  • Organic Chemistry

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