Peroxidatic activity of metalloporphyrin binding to serum albumin: Enhancement effect of serum albumin on metalloporphyrin catalyzed luminol chemiluminescence reaction

The metalloporphyrin (M-P) catalyzed luminol-H2O2 chemiluminescence (CL) system can be significantly enhanced in the presence of serum albumins. The enhancement may be explained in terms of the formation of a molecular complex between M-P and serum albumin. The hydrophobic and coordination interactions between M-P and serum albumin were confirmed by comparing the degree of enhancement by the protein on different types of M-P catalyzed CL reactions and by comparing the catalytic activity of M-P/bovine serum albumin (BSA) and M-P/BSA/anti-BSA complexes. Only the non-ionic M-P catalyzed CL reaction was significantly enhanced, and the enhanced CL reaction was inhibited by an immunoreaction. The optimum conditions of the M-P/albumin complex catalyzed CL reaction were evaluated by using a flow-injection system, which was very similar to that using hemoglobin as the catalyst. A brief prospective on the general applicability of the enhanced CL reaction for the determination of serum albumin (2.5–500 μg/ml) is given.