Antioxidant activity of conjugation of metalloporphyrin combining with bovine serum albumin

Abstract

In this work, two kinds of water-insoluble metalloporphyrin (MP), meso -tetraphenylporphyrin metal complexes (MTPP, M: Zn Ⅱ , Co Ⅱ ) and meso -tetra( p -hydroxylphenyl)porphyrin metal complexes (MTpHPP, M: Zn Ⅱ , Co Ⅱ ), were combined into bovine serum albumin (BSA), a kind of stable and soluble biopolymer. The obtained water-soluble metalloporphyrin at BSA conjugates (MP@BSA) have been characterized by UV-vis spectra, PAGE gel electrophoresis and circular dichroism spectra. It indicated that the water-solubility and stability of metalloporphyrins were significantly increased after being bound into bovine serum albumin. Their SOD-like activities for scavenging superoxide anion free radical (O 2 · - ) were determined by NBT assay and compared with natural antioxidant. The activities of MP@BSA were more decuple than that of metalloporphyrins. The EC 50 values of MP@BSA were 600-fold and 40-fold higher than that of Vitamin C (VC) and BSA, respectively. The hydroxyl substituted metalloporphyrin showed more active than that of MTPP, and EC 50 of CoTpHPP@BSA got to 1.5 mmol/L. Compared with natural Cu,Zn-SOD, the analog quantity of CoTpHPP@ BSA reached 2.73%.