Physicochemical properties and oxygen affinity of glutaraldehyde polymerized crocodile hemoglobin: the new alternative hemoglobin source for hemoglobin-based oxygen carriers

Abstract

Hemoglobin-based oxygen carriers (HBOCs) are modified stroma-free hemoglobin molecules used in developing a blood substitute for therapeutic usage. In order to prevent hemoglobin dissociation, glutaraldehyde (GTA) was used to generate high-molecular weight heterogeneous crocodile hemoglobin (Poly-cHb). This work, Poly-cHb was created using various GTA concentrations, ranging from 0.025-0.150% (v/v). Physicochemical properties were investigated that were comparable GTA polymerized human hemoglobin (Poly-hHb). This study has revealed that GTA polymerization increases the molecular size of Native-cHbs from 14.10 nm over a range from 16.31 to 54.27 nm. Moreover, this polymerization alters the secondary structure and heme environment by decreasing the helicity ratio from 1.00 to 0.95 at the highest condition and exhibits hypochromic shift of the Soret band to be 0.88 times lower than the native. However, all Poly-cHbs still possessed higher oxygen affinity than that of Poly-hHbs with average P50 values of 13 and 21 mmHg, respectively. Although, polymerization affected the overall Poly-cHb structure slightly, but compensated by decreasing the denaturation level to lower than 10%. Thus, it is interesting to note that Poly-cHb may advantageously provide effective oxygen carriage and ability for pasteurization, which may benefit the search for new alternative hemoglobin sources for HBOC development.

GRAPHICAL ABSTRACT

KEYWORDS:

• Hemoglobin-based oxygen carrier (HBOC)
• polymerization
• modified hemoglobin
• stroma-free hemoglobin
• Siamese crocodile
• glutaraldehyde

Acknowledgements

I appreciate to especially thank Sriracha Moda Co., Ltd. (Chon Buri, Thailand) for supplying the crocodile blood sample and Department of Biochemistry, Faculty of Science, Khon Kaen University for providing the scientific instruments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was financially supported by the Office of the Higher Education Commission; the Army Research and Development Office; Protein and Proteomics Research Center for Commercial and Industrial Purposes; and Research Fund for Supporting Lecturer to Admit High Potential Student to study and Research on His Expert Program Year 2017, Khon Kaen University [Grant number 601T106].