Enhancing the peroxidase-like activity of ficin via heme binding and colorimetric detection for uric acid.

Ficin, a classical sulfhydryl protease, was found to possess intrinsic peroxidase-like activity. In this paper, we have put forward a novel strategy to improving the peroxidase-like activity of ficin through binding heme. Heme-ficin complexes were successfully obtained by simple one-step syntheticism. The results demonstrated that the catalytic activity and efficiency of heme-ficin complexes were about 1.7 times and 3 times higher than those of native ficin, respectively. Taking advantages of the high peroxidase-like activity, the heme-ficin complexes were used for colorimetric determination of uric acid with a low detection limit of 0.25 μM. Based on the excellent selectivity and sensitivity, we detected the concentration of uric acid in human serum successfully. On the basis of these findings, the heme-ficin complexes are promising for wide applications in various fields. Thus we not only optimized the peroxidase-like activity of the ficin, but also established a new strategy for development of artificial enzyme mimics by mimicking the architecture of the active site in horseradish peroxidase.