Some properties of hemoglobin A2

✍ Scribed by Helen M. Ranney; Ruby Lam; Gwen Rosenberg

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 469 KB
• Volume: 42
• Category: Article
• ISSN: 0361-8609
• DOI: 10.1002/ajh.2830420121

✦ Synopsis

Abstract

While no significant physiologic function of hemoglobin A~2~ (Hb A~2~), the minor basic component of human hemoglobin, has been recognized, only its oxygen equilibria have been studied in detail. Since hemoglobin A~2~ and its oxidative denaturation product, hemichrome A~2~, bind to the red cell membrane, particularly to band 3, to a greater extent than do Hb A or hemichrome A, some of the properties of Hb A~2~ that might influence hemoglobin‐membrane association were examined. Hemoglobin A~2~ exhibited slightly increased susceptibility to autoxidation to methemoglobin. No differences were noted between methemoglobins A and A~2~, including the rates of enzymatic reduction and stability of the heme‐globin linkage. Oxyhemoglobin A~2~ had a slightly lower solubility in phosphate buffer than did hemoglobin A. While the hemichromes (prepared with phenylhydrazine) of hemoglobins A~2~ and A had the same optical spectra, the A~2~ hemichrome exhibited greater stability. It is suggested that the differences in products of oxidative denaturation may provide the basis for functional differences between hemoglobins A~2~ and A. © 1993 Wiley‐Liss, Inc.