Stability of a potential blood substitute, HbXL99 alpha, under high pressure.
One important criteria for a plasma circulating hemoglobin blood substitute is resistance to subunit dissociation. For this reason, cross-linked hemoglobins (with low oxygen affinities) are being specifically designed to serve as potential blood substitutes. An example is HbXL99 alpha, cross-linked between the alpha-subunits [PNAS (1987) 84:7280]. In the study presented here, the effects of up to 2 kilobars of pressure on the intrinsic fluorescence of HbXL99 alpha, HbA, and myoglobin were compared. Hemoglobin solutions were studied between 0.01-0.1g% in potassium phosphate or Hepes buffers, pH 7.4. Results show HbA exhibits a decrease in fluorescence intensity as a function of pressure. In contrast, HbXL99 alpha as well myoglobin (a monomer) show essentially no significant intrinsic fluorescence changes as a function of pressure. These results suggest that HbXL99 alpha is stable as a tetramer up to approximately 2 kilobars of pressure. In addition, high pressure intrinsic fluorescence studies provide a suitable technique for determining the subunit stability of hemoglobins.
Hirsch
R E
RE
Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461.
Friedman
J M
JM
Harrington
J R
JR
Scarlata
S F
SF
Harrington
J P
JP
D000818:Animals; D001241:Aspirin / Q000031:analogs & derivatives* / Q000737:chemistry; D006441:Hemoglobin A / Q000737:chemistry; D006454:Hemoglobins / Q000737:chemistry*; D006801:Humans; D006874:Hydrostatic Pressure; D066298:In Vitro Techniques; D009211:Myoglobin / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D014907:Whales
D006454:Hemoglobins; D009211:Myoglobin; C053936:hemoglobin XL99alpha; D006441:Hemoglobin A; D001241:Aspirin