Construction of manganese porphyrin modified hemoglobin complex and its antioxidant activities

Manganese 5,10,15,20-tetrakis(N-methyl-2-yl) porphyrin (MnT2MePyP) was introduced to hemoglobin to use it as a drug carrier. Reconstituted hemoglobin was reacted with pyridoxal-5-phosphate and borohydride to yield pyridoxalated reconstituted hemoglobin (PLPrHb). The reaction of PLPrHb with activated polyethyleneglycol gave pegylated reconstituted hemoglobin (PEGrHb). PEGrHb was polymerized using glutaraldehyde to yield cross-linked pegylated reconstituted hemoglobin (Cross-link PEGrHb). The number average moleculer weight of Cross-link PEGrHb was estimated to be 1.0 _Xt 10⁵ by GPC. The modification of hemoglobin was checked by using SDS-PAGE. Stopped flow analysis showed a high SOD activity of Cross-link PEGrHb. A pharmacokinetic study of ¹²⁵I-labelled Cross-link PEGrHb that was infused into mice revealed a long-term blood circulation. The novel Manganese porphyrin modified hemoglobin complex was found to remain long-term in the blood circulation without being removed by excretion. These results showed that this complex can be used as a high performance antioxidant.