Fixation of aldehydic dextrans onto human deoxyhemoglobin

Area of Science:

• Biochemistry
• Biomaterials Science
• Hematology

Background:

• Native adult human hemoglobin (Hb) requires modification for use as a physiological oxygen carrier.
• Current Hb modification methods often result in molecular heterogeneity, necessitating complex fractionation.
• Key modifications include pyridoxylation to reduce oxygen affinity and polymerization to enhance circulation half-life.

Purpose of the Study:

• To develop hemoglobin derivatives with controlled low oxygen affinity and narrow molecular weight distribution.
• To create stable, reversible oxygen carriers suitable for in vivo applications.
• To investigate the effect of crosslinking on hemoglobin's allosteric site and oxygen-binding properties.

Main Methods:

• Linking dextran polyaldehydic derivatives to deoxyhemoglobin at pH 8.
• Utilizing inositolhexaphosphate as an allosteric effector during conjugation.
• Employing NaBH4 for stabilization of polymer-hemoglobin derivatives.

Main Results:

• Synthesized hemoglobin derivatives exhibited low oxygen affinity and a narrow molecular weight distribution.
• Crosslinking likely stabilized the deoxy structure by blocking the allosteric site.
• Conjugates demonstrated stable, reversible oxygen-carrying capacity comparable to blood after NaBH4 treatment.

Conclusions:

• Dextran-conjugated hemoglobin offers a promising approach for creating effective oxygen carriers.
• The modification strategy allows for tuning oxygen affinity and improving stability for potential therapeutic use.
• Further research may optimize these Hb derivatives for transfusion medicine and other applications.