Article ID Journal Published Year Pages File Type
1235446 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2007 4 Pages PDF
Abstract
This paper discussed the quantitative influence of Cu(II) on the interaction between horseradish peroxidase (HRP) and sulfite (SO32−), which is a derivate of sulfite dioxide in human bodies, by using fluorescence spectrum and ultraviolet (UV) absorption spectrometry in vitro. The results show that under the conditions of physiological pH and room-temperature, Cu(II) can bind strongly with both the protein part and the ferroporphyrin part in HRP at a low concentration (10−4 mol L−1), and the combination constants are 2.047 × 103 and 7.66 × 102 L mol−1, respectively. Under the same conditions, SO32− at low concentrations (<0.15 mol L−1) has little quenching for the fluorescence of HRP at 330 nm, and the combination constant is 0.108 L mol−1. While the fluorescence intensity at 440 nm enhance gradually with the increased concentration of SO32− (<0.1 mol L−1), and the combination constant is 8.219 L mol−1. These indicate that SO32− at low concentration has little reaction with the enzyme protein part in HRP but obvious reaction with the ferroporphyrin part in HRP. After SO32− at low concentrations is added into the HRP-Cu(II) binary system, the reaction constants between SO32− and the enzyme protein part in HRP increase rapidly. Compared with the absence of Cu(II), the combination constant of SO32− with the enzyme protein part in HRP increases nearly 70 times with a certain Cu(II) concentration (5.0 × 10−4 mol L−1) in the system. However, the presence of Cu(II) in the system has little effect on the reaction constants between SO32− and the ferroporphyrin part in HRP.
Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
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