| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1179536 | Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics | 2014 | 7 Pages |
•PEG-Hb is prepared using acylation chemistry with protection of Cys-93(β) by PEG20K.•Heme and tetramer stability of PEG-Hb were increased by protection of Cys-93(β).•Autoxidation and O2 affinity of PEG-Hb were decreased by protection of Cys-93(β).
As a potential hemoglobin (Hb)-based oxygen carrier (HBOC), the PEGylated Hb has received much attention for its non-nephrotoxicity. However, PEGylation can adversely alter the structural and functional properties of Hb. The site of PEGylation is an important factor to determine the structure and function of the PEGylated Hb. Thus, protection of some sensitive residues of Hb from PEGylation is of great significance to develop the PEGylated Hb as HBOC. Here, Cys-93(β) of Hb was conjugated with 20 kDa polyethylene glycol (PEG20K) through hydrazone and disulfide bonds. Then, the conjugate was modified with PEG5K succinimidyl carbonate (PEG5K-SC) using acylation chemistry, followed by removal of PEG20K Hb with hydrazone hydrolysis and disulfide reduction. Reversible conjugation of PEG20K at Cys-93(β) can protect Lys-95(β), Val-1(α) and Lys-16(α) of Hb from PEGylation with PEG5K-SC. The autoxidation rate, oxygen affinity, structural perturbation and tetramer instability of the PEGylated Hb were significantly decreased upon protection with PEG20K. The present study is expected to improve the efficacy of the PEGylated Hb as an oxygen therapeutic.
