title: Inhibition of methemoglobin formation in aqueous solutions under aerobic conditions by the addition of amino acids.
abstract: Hemoglobin (Hb) as an important iron-containing oxygen-transport protein is easily oxidized to the ferric met-form, methemoglobin (metHb), and loses the capacity of binding oxygen during storage. In this study, the experimental data indicate that the presence of Tyr and Glu significantly suppress the metHb formation in the Hb solutions in aqueous environment under aerobic conditions at the temperature of 25 and 37 °C, respectively. At pO2 of 144Torr the metHb percentage in the Hb solutions was the lowest with less than 10% at day 7 after incubation with Tyr at the ratio of 24 at pH 9.5 at 25 °C. At 37 °C, the metHb percentage did not reach 5% after 12h of incubation with Glu at the ratio of 24 at pH 9. Molecular simulation analysis suggest that the presence of Tyr or Glu may contribute to the formation of the breakwater network, the stabilization of distal histidine, the changes in the size of heme pocket, and eventually result in the inhibition of metHb formation. This study provides insight into a new design for Hb-oxygen based carriers with strongly inhibition of metHb formation in aqueous environment under aerobic conditions, even at physiological temperature in vitro.
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yuping
authors.initials: Y
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Chunlong
authors.initials: C
authors.lastname: Li
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Su
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China. Electronic address: xuxia@home.ipe.ac.cn.
authors.forename: Xia
authors.initials: X
authors.lastname: Xu
mesh_terms: D000332:Aerobiosis; D000596:Amino Acids / Q000737:chemistry* / Q000494:pharmacology; D006418:Heme / Q000737:chemistry / Q000378:metabolism; D006454:Hemoglobins / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008706:Methemoglobin / Q000037:antagonists & inhibitors / Q000737:chemistry*; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011485:Protein Binding; D011487:Protein Conformation; D055550:Protein Stability; D012996:Solutions
chemical_list: D000596:Amino Acids; D006454:Hemoglobins; D012996:Solutions; D006418:Heme; D008706:Methemoglobin
keywords: Amino acid; Hemoglobin; Methemoglobin; Molecular simulation; Stability