Hydrogen peroxide modification of human oxyhemoglobin.
The effect of H2O2 on the primary structure of OxyHb was studied. Upon treatment of OxyHb with H2O2 ([Heme]/[H2O2] = 1), tryptophan and methionine residues of the beta-chain were modified. Treatment of ApoHb with H2O2 resulted in the modification of histidine and methionine residues in both globin chains. Tryptophan residues were unaffected. Modification of methionine residues in both the beta-chain of OxyHb and ApoHb probably results from the direct oxidation of methionine by H2O2. The modification of histidine residues in ApoHb may be mediated by a metal-catalyzed oxidation system comprised of H2O2 and histidine-bound iron. The H2O2-mediated modification of tryptophan in the OxyHb beta-chain, however, requires the heme moiety.
Steffek
R P
RP
Department of Biochemistry, Wake Forest University Medical Center, Bowman Gray School of Medicine, Winston-Salem, North Carolina 27103.
Thomas
M J
MJ
D000596:Amino Acids / Q000737:chemistry; D001059:Apoproteins / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D005914:Globins / Q000737:chemistry; D006418:Heme / Q000737:chemistry; D006441:Hemoglobin A / Q000737:chemistry / Q000187:drug effects*; D006454:Hemoglobins / Q000737:chemistry; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007501:Iron / Q000737:chemistry; D010108:Oxyhemoglobins / Q000737:chemistry / Q000187:drug effects*; D010449:Peptide Mapping; D014357:Trypsin
D000596:Amino Acids; D001059:Apoproteins; D006454:Hemoglobins; D010108:Oxyhemoglobins; C023478:apohemoglobin; D006418:Heme; D005914:Globins; D006441:Hemoglobin A; C029774:oxyhemoglobin A; D006861:Hydrogen Peroxide; D007501:Iron; D014357:Trypsin