Cross-linked bis-hemoglobins: connections and oxygen binding.
Covalently linked pairs of cross-linked hemoglobin tetramers ("bis-tetramers", shown schematically as 6-8) were prepared by reacting hemoglobin A with tetrakis acyl phosphate esters (3-5). The effects of the link between tetramers are observed in the oxygen-binding properties of the bis-tetramers: they bind oxygen cooperatively but with Hill coefficients (n(50)) lower than that of the native protein and with a high average affinity. The bis-tetramers with longer connections between tetramers show a higher n(50), suggesting that steric interactions between the tetramers affect cooperativity. These results correlate to the observed reduced vasoactivity of heterogeneous solutions of oligomeric cross-linked hemoglobin tetramers.
Gourianov
Nikolai
N
Davenport Chemical Laboratories, Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6.
Kluger
Ronald
R
D003432:Cross-Linking Reagents / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D006441:Hemoglobin A / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D010755:Organophosphates / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry* / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D003432:Cross-Linking Reagents; D010755:Organophosphates; D006441:Hemoglobin A; D010100:Oxygen