Differential interaction of cerium chloride with bovine liver catalase: A computational and biophysical study.

In this study, Cerium chloride-induced conformational changes of Bovine Liver Catalase (BLC) has been investigated by molecular docking and further supported by various biophysical techniques. The temporal change of catalytic activity of BLC has also been studied in presence of Ce(III) with different buffer solution in vitro at 25 °C. The differential binding of Ce(III) to BLC observed by simulation study was well supported by the differential regulation of BLC activity in different buffers. After 1 h of incubation with CeCl3, the reduction in activity of BLC was maximum in MOPS, HEPES and Tris buffer, whereas no change in activity was noticed in phosphate buffer. Isothermal Titration Calorimetric (ITC) study also supports the differential binding of Ce(III) to BLC in different buffers. Ce(III)-induced conformational transition in BLC was followed as a function of concentration. Nevertheless, with 24 h incubation of CeCl3 the activity of BLC was highest with higher molar concentration of CeCl3 suggesting the conformational stability of BLC in presence of Ce(III). The compromised activity of BLC in response to Ce(III) is due to the induced conformational change and the degree of change in secondary conformation of BLC was maximum in MOPS, HEPES and Tris and least in phosphate buffer. Therefore, the reduced activity of BLC is controlled by the direct interaction of Ce(III) in the active site of BLC in Tris buffer or indirect interaction of Ce(III) in the non-active site of BLC in MOPS and HEPES buffer.