Effect of modification on physicochemical and biological properties of haptoglobin. VI. Reaction with azlactone of p-nitrobenzoyl-valine.
The azlactone of p-nitrobenzoyl-valine (Nbz-Val) has been used for modification of xi-amino groups of lysine in haptoglobin type 1-1, in hemoglobin, and in the haptoglobin-hemoglobin complex. By the use of this reagent 95% of amino groups in haptoglobin and 90% in hemoglobin have been blocked without any changes in peroxidase activity of the formed complexes: Nbz-Val.haptoglobin with hemoglobin, Nbz-Val. hemoglobin with haptoglobin, and Nbz-Val.(haptoglonin-hemoglobin). After reduction and reoxidation, Nbz-Val.haptoglobin was found to retain 90% of peroxidase activity when complexed with hemoglobin. Beta chains separated either from haptoglobin or Nbz-Val.haptoglobin showed 15% of peroxidase activity in the complex with hemoglobin, alpha chains of the same origin were completely inactive. Whereas recombination of haptoglobin from alpha and beta chains resulted in 42% hemoglobin-binding capacity, renaturation of Nbz-Val.haptoglobin from separated subunits was found to proceed with almost 100% yield. In immunodiffusion with rabbit anti-haptoglobin or anti-Nbz-Val.haptoglobin sera, preparations of haptoglobin and Nbz-Val.haptoglobin after reduction and reoxidation or after recombination from separated subunits gave similar precipitation arcs showing the reaction of immunological identity.
D006242:Haptoglobins / Q000276:immunology; D006454:Hemoglobins; D006801:Humans; D009579:Nitrobenzoates; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000032:analysis; D010544:Peroxidases / Q000378:metabolism; D014633:Valine / Q000031:analogs & derivatives*
D006242:Haptoglobins; D006454:Hemoglobins; D009579:Nitrobenzoates; D010446:Peptide Fragments; D010544:Peroxidases; D014633:Valine