Tris(3, 5-Dibromosalicyl) Tricarballylate Crosslinked Hemoglobin: Functional Evaluation

Abstract

Both oxy and deoxy human hemoglobin A were crosslinked with tris(3,5-dibromosalicyl) tricarballylate. The major species from both reactions contained an inter-subunit crosslink. The denaturation transition (T_m) of the oxy crosslinked hemoglobin increased 14.5 °C and that of deoxy crosslinked hemoglobin, 13.0 °C. The apparent rate constant (k_app) of autoxidation for oxy crosslinked hemoglobin remained the same as native hemoglobin but that of the deoxy crosslinked hemoglobin increased by 34%. The higher oxygen affinity and lower cooperativity of the crosslinked proteins compared with native hemoglobin indicated that the crosslink shifted the conformation to the R state.