Acute and Long-Term Stability Studies of Deoxy Hemoglobin and Characterization of Ascorbate-Induced Modifications

• Published in: Journal of pharmaceutical sciences 1999-01, Vol.88 (1), p.79-88
• Main Authors: Kerwin, Bruce A., Akers, Michael J., Apostol, Izydor, Moore‐Einsel, Camille, Etter, Jeffrey E., Hess, Edward, Lippincott, Julie, Levine, Joseph, Mathews, Antony J., Revilla‐Sharp, Patricia, Schubert, Ross, Looker, Douglas L.
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Ascorbic Acid - chemistry; Biological and medical sciences; Drug Stability; Electrophoresis, Polyacrylamide Gel; Ferrous Compounds - chemistry; Fundamental and applied biological sciences. Psychology; Hemoglobins - chemistry; Hemoproteins; Metalloproteins; Oxygen - chemistry; Pepsin A - chemistry; Peptide Mapping; Polysorbates; Proteins; Scattering, Radiation; Solutions; Trypsin - chemistry
• ISSN: 0022-3549; 1520-6017
• DOI: 10.1021/js980221r

The reaction of ascorbate with recombinant hemoglobin (rHb1.1) in the presence of differing partial pressures of oxygen was studied. In the presence of 15 000 ppm (1.5%) residual oxygen, ascorbate/oxygen‐mediated reactions resulted in an increased rate of autoxidation, modification of the β‐globin, increased oxygen affinity and decreased maximum Hill coefficient. One of the observed modifications to the β‐globin was a 72 Da addition to its N‐terminus. Detailed characterization indicates the modification was an imidazo‐lidinone type structure. Thorough deoxygenation of the hemoglobin solution to