Abstract
Abstract The interaction between human hemoglobin and haptoglobin has been followed by measuring the quenching of haptoglobin fluorescence associated with complex formation. The effects of varying the concentration of the reactants suggest that hemoglobin tetramers do not react with haptoglobin, but that hemoglobin subunits are involved. Separated α chains of hemoglobin react with haptoglobin; although separated β chains do not do so, they react rapidly with a previously incubated mixture of haptoglobin and α chains. It is suggested that the haptoglobin site binds α chains specifically, and that the normal reaction between hemoglobin and haptoglobin proceeds either by consecutive binding of α and β monomers or by attachment of αβ dimers through the α chain. The rate of the reaction is markedly dependent on conditions: the observed second order constant may reach 4 x 106 m-1 sec-1, and the true value is probably 7 x 106 m-1 sec-1.
Highlights
Tetramers containing cr chains blocked by HMB and /3 chains with the -SH groups free (02HMB /3~) were obtained by incubating aHMB chains prepared by the Bucci and Fronticelli method and Hb H (&)
The binding of hemoglobin to Hp l-l appears to be the reaction between 1 molecule of Hp l-l and 1 molecule of hemoglobin [1]
The results of the experiments presented suggest that the reaction between haptoglobin and hemoglobin may proceed via a hemoglobin subunit
Summary
The interaction between human hemoglobin and haptoglobin has been followed by measuring the quenching of haptoglobin fluorescence associatedwith complex formation. Chains and that the normal reaction between hemoglobin and haptoglobin proceeds either by consecutive binding of The hemoglobin-haptoglobin reaction appeared to be well suited for kinetic studies by rapid reaction methods because of its irreversibility and because it was anticipated that binding would be associated with quenching of the aromatic amino acid fluorescence of the haptoglobin by the heme groups of hemoglobin, which have effective quenching radii of some 42 A [10]. Comparisons between the reaction of haptoglobin with Hb A, Hb H, and The complex which is formed with the globin moiety of hemoglobin [2] probably involves the B chains of haptoglobin [3]. Service Grants AM 04502 and GM 14276-02 and Grant G-6549 from the Life Insurance Medical Research Fund
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
