Apohemoprotein is focused on the field of theranostics, serving as a porphyrin carrier. Hemoglobin (Hb) consists of α₂β₂ tetramer with iron(II)-protoporphyrin IX (heme) bound to each globin. However, heme-removed Hb (apoHb) causes dissociation at αβ interfaces and aggregation under physiological conditions. We synthesized a stable apoHb derivative comprising intramolecular-crosslinked apoHb (apoXHb) and human serum albumin (HSA), apoXHb-HSA₃. ApoXHb-HSA₃ engendered no aggregates in the physiological solutions. Moreover, apoXHb-HSA₃ was reconstituted with zinc(II)-protoporphyrin IX (ZnP), generating ZnXHb-HSA₃, a potent photosensitizer for photodynamic therapy (PDT). The photophysical properties of ZnXHb-HSA₃ were identical to those of zinc-substituted XHb (ZnXHb). Cellular uptake behavior was evaluated using various cancer cell lines. ZnXHb-HSA₃ released ZnP around the cells, and the free ZnP penetrated cell membranes. In contrast, protein units were not observed within the cells. ZnXHb-HSA₃ showed no cytotoxicity under dark conditions and demonstrated superior PDT activity in comparison to naked ZnXHb. ZnXHb-HSA₃ acts as an innovative porphyrin carrier for enhanced PDT.

中文翻译：

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锌取代的血红蛋白-白蛋白簇作为卟啉载体用于增强光动力治疗

阿朴血红素蛋白专注于治疗诊断学领域，作为卟啉载体。血红蛋白 (Hb) 由 α ₂ β ₂四聚体组成，每个球蛋白均结合有铁 (II)-原卟啉 IX（血红素）。然而，去除血红素的 Hb (apoHb) 会导致 αβ 界面解离并在生理条件下聚集。我们合成了包含分子内交联的apoHb (apoXHb) 和人血清白蛋白(HSA) 的稳定apoHb 衍生物，apoXHb-HSA ₃。 ApoXHb-HSA ₃在生理溶液中不产生聚集体。此外，apoXHb-HSA ₃用锌(II)-原卟啉IX (ZnP) 重构，生成ZnXHb-HSA ₃，这是一种用于光动力疗法(PDT)的有效光敏剂。 ZnXHb-HSA ₃的光物理性质与锌取代的XHb (ZnXHb) 相同。使用各种癌细胞系评估细胞摄取行为。 ZnXHb-HSA ₃在细胞周围释放ZnP，并且游离的ZnP穿透细胞膜。相反，在细胞内没有观察到蛋白质单位。 ZnXHb-HSA ₃在黑暗条件下没有表现出细胞毒性，并且与裸露的 ZnXHb 相比表现出优异的 PDT 活性。 ZnXHb-HSA ₃作为一种创新的卟啉载体，可增强 PDT。