Oxygen-Carrying Plasma Hemoprotein 'Albumin-Heme': Nitric Oxide Binding and Physiological Responses after Administration in vivo

摘要

Recombinant human serum albumin complexed with tetraphenylporphi-natoiron(II) derivative, "album in-heme (rHSA-FeP)", is a synthetic oxygen (O_2)-carrying plasma hemoprotein, which becomes a new class of red blood cell substitute. The UV-vis. absorption and ESR spectroscopy revealed that rHSA-FeP formed six-coordinate nitrosyl complex after exposure of nitric oxide (NO) gas. Although the NO-binding affinity of rHSA-FeP (P_(1/2)~(NO): 1.7 x 10~(-6) Torr, pH 7.3, 25°C) is 9-fold higher compared to that of hemoglobin (Hb), the administration of this artificial hemoprotein solution into anesthetized rat does not induce an acute increase in blood pressure (hypertension), which is often observed in Hb-based O_2-carriers due to the depletion of NO (endothelial derived relaxing factor).