Studies on the depolymerization of the heme-proteins

摘要: Abstract The dissociation of an avian hemoglobin, chick oxyhemoglobin 1, was studied in the presence ionic type (LiCl, NaCl, KCl and CaCl 2 ) non-ionic solutes (formamide, urea, guanidine hydrochloride 2-chloroethanol), high alkaline pH conditions. An increase solute concentration alkalinity media produced increasing as measured by sedimentation velocity coefficient values. Sedimentation equilibrium studies employing ultraviolet monochromator automatic double-beam photoelectric scanner revealed that state exists between different subunits, tetramer, dimer, monomer, depending on condition media. Alkaline hemoglobin to half-molecule began at 10.6 completed 11.6. degree implies is more resistant than mammalian hemoglobins, adult human bovine hemoglobins. Localized conformational change evaluated solvent perturbation difference spectra observed with , all solutes. Spectrophotometric titration tyrosine ionization showed 17 residues amino acid analysis 15 were ionized 12.5–pH 12.75 8 became available 10.3 11.3 where tetrameric dissociated half-molecule. Urea effective reducing heme-heme interaction producing hyperbolar oxygen curves NaCl. transition from sigmoidic curve dependent concentration.