Preparation and Characterization of Dimeric Bovine Hemoglobin Tetramers

Hu, Tao; Li, Dongxia; Su, Zhiguo

doi:10.1023/b:jopc.0000005455.94103.b8

Cited by 13 publications

(6 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, Su and co-workers reported bis-tetrameric bovine hemoglobin that was prepared selectively using glutaraldehyde in combination with column-adsorbed bovine hemoglobin. The material has an increased oxygen affinity and significant cooperativity (n 50 ) 1.72) (24). The Hill coefficient is larger than we see in the structurally defined human hemoglobin bis-tetramers (4,5).…”

Section: Discussionmentioning

confidence: 70%

Conjoined Hemoglobins. Loss of Cooperativity and Protein−Protein Interactions

Gourianov

Kluger

2005

Biochemistry

View full text Add to dashboard Cite

Hemoglobin cross-linked as a bis(isophthalamide) of the epsilon-amino groups of lysine 82 of each beta-subunit binds and releases oxygen with a Hill coefficient indicative of cooperative oxygen binding (typically approximately 2.0). However, connecting two such cross-linked tetramers with a relatively short covalent linkage produces cross-linked bis-tetramers that bind oxygen with Hill coefficients near unity. To separate the effect of the linkages from the effects of protein-protein interactions in the conjoined proteins, reagents (1 and 2) were used to produce bis-tetramers (A and B). These have a considerably greater distance between cross-linked tetramers than earlier examples. Yet, the bis-tetramers (A and B) bind oxygen with minimal cooperativity (n(50) = 1.4, 1.2). To assess the effect of the linkage itself, cross-linked tetramers (Cand D) were prepared from reactions with the same reagents. These bind oxygen with cooperativity similar to that of cross-linked tetramers without the extended chain (C, n(50) = 2.0; D, n(50) = 1.8). Other tetramers (E and F) with flexible, saturated hydrocarbon appendages were also prepared. These also showed cooperativity in oxygen binding (E, n(50) = 1.7; F, n(50) = 1.8) despite their high degree of hydrophobicity. Thus, the intertetrameric linkages themselves do not induce the loss of cooperativity, leading to the conclusion that solution effects of the tetramers upon one another are the source of the decline in cooperativity: protein-protein interactions are most significant in disrupting the cooperativity of the bis-tetramers, regardless of the span or composition of the linker. This suggests that effects of oligomerization of hemoglobin within red cell substitutes should be considered in terms of such interactions.

show abstract

Section: Discussionmentioning

confidence: 70%

Conjoined Hemoglobins. Loss of Cooperativity and Protein−Protein Interactions

Gourianov

Kluger

2005

Biochemistry

View full text Add to dashboard Cite

show abstract

“…Experimental results also demonstrate that oxygen release by conjugated Hbs are more susceptible to hypoxic conditions (oxygen < 6%) rather than the changes in cellular or media pH. The altered cooperative nature and Bohr Effect observed is common with most other polymerization techniques 35,36 and may be attributed to transformation of Glu-101 beta to acidic Bohr group, which is in close proximity to Lys-99 alpha in oxyhemoglobin that may be involved in crosslinking. 37 In experiments involving hypoxic conditions, from among the different conjugates, conjugates with 1:10 (Hb/PEG) ratio were chosen for MTT viability studies.…”

Section: Discussionmentioning

confidence: 78%

Hemoglobin Conjugates with Antioxidant Enzymes (Hemoglobin-Superoxide Dismutase-Catalase) via Poly(Ethylene Glycol) Crosslinker for Protection of Pancreatic Beta RINm5F Cells in Hypoxia

Nadithe

Bae

2011

Tissue Engineering Part A

View full text Add to dashboard Cite

A low p50 hemoglobin (Hb) (p50 indicates O(2) tension at which Hb is half-saturated)-based oxygen carrier conjugated to antioxidant enzymes via dicarboxymethylated poly(ethylene glycol) (PEG) linker may have the beneficial effect in protecting pancreatic beta cells from severe hypoxia at transplantation sites. In this study, the oxygen dissociation curves, Hill plots, Bohr Effect, and oxygen content of Hb conjugates were measured. The protective effect due to incubation of Hb-conjugates (Hb/PEG molar ratio 1:10) with pancreatic beta cells (RINm5F) against hypoxia (6%, 3%, and 1% oxygen) was evaluated by an MTT assay and confocal microscopy. Quantitatively, Hb conjugates with antioxidant enzymes offered statistically significant protection (p<0.01, increased viability ∼80%) from hypoxia compared to control cells in 1% oxygen environment. Confocal images also showed that the low p50 Hb conjugates with antioxidants protected RINm5F cells from hypoxia.

show abstract

“…Hb polymerized by glutaraldehyde in aqueous solution often leads to uncontrolled polymerization and multiple aggregates of varying composition, ranging from two to six Hb tetramers are obtained. Using an ion‐exchange matrix, dimeric Hb tetramers were formed predominantly on the SP, which can be easily separated from the unreacted monomer [74] . Subsequent O 2 binding studies indicate that the dimers still retain their activity and exhibit lower viscosity compared to commercially available polyHb due to the low polymerization degree thus making them easier to administrate.…”

Section: Sps As a Versatile Platform For Preparing Precise Protein Olmentioning

confidence: 99%

Solid‐Phase Protein Modifications: Towards Precision Protein Hybrids for Biological Applications

Kuan

Raabe

2020

ChemMedChem

View full text Add to dashboard Cite

Proteins have attracted increasing attention as biopharmaceutics and diagnostics due to their high specificity, biocompatibility, and biodegradability. The biopharmaceutical sector in particular is experiencing rapid growth, which has led to an increase in the production and sale of protein drugs and diagnostics over the last two decades. Since the first‐generation biopharmaceutics dominated by native proteins, both recombinant and chemical technologies have evolved and transformed the outlook of this rapidly developing field. This review article presents updates on the fabrication of covalent and supramolecular fusion hybrids, as well as protein‐polymer hybrids using solid‐phase approaches that hold great promise for preparing protein hybrids with precise control at the macromolecular level to incorporate additional features. In addition, the applications of the resultant protein hybrids in medicine and diagnostics are highlighted where possible.

show abstract

Preparation and Characterization of Dimeric Bovine Hemoglobin Tetramers

Cited by 13 publications

References 15 publications

Conjoined Hemoglobins. Loss of Cooperativity and Protein−Protein Interactions

Conjoined Hemoglobins. Loss of Cooperativity and Protein−Protein Interactions

Hemoglobin Conjugates with Antioxidant Enzymes (Hemoglobin-Superoxide Dismutase-Catalase) via Poly(Ethylene Glycol) Crosslinker for Protection of Pancreatic Beta RINm5F Cells in Hypoxia

Solid‐Phase Protein Modifications: Towards Precision Protein Hybrids for Biological Applications

Contact Info

Product

Resources

About