Different susceptibilities to intracellular proteases of hemoglobin and hemoglobin-haptoglobin complex.
The susceptibilities of hemoglobin and hemoglobin-haptoglobin complex to intracellular proteases differ significantly. Hemoglobin and hemoglobin-haptoglobin complex are degested in the regions of pH 5.5-2.5 and 4.0-2.5 respectively, having pH optima at pH 4.0 and 3.0 respectively, by intracellular proteases from rat and mouse liver or spleen. The difference in proteolytic susceptibility is found to be due to the different stabilities to acid among hemoglobin derivatives as evidenced by the measurements of their helical contents in acidic pH.
D000818:Animals; D006242:Haptoglobins; D006454:Hemoglobins; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008247:Lysosomes / Q000201:enzymology; D051379:Mice; D010447:Peptide Hydrolases / Q000378:metabolism*; D011487:Protein Conformation; D051381:Rats; D013154:Spleen / Q000201:enzymology
D006242:Haptoglobins; D006454:Hemoglobins; D010447:Peptide Hydrolases